all: REVERSE MERGE dev.unified (d558507) into master

This commit is a REVERSE MERGE. It merges dev.unified back into its parent branch, master. This marks the end of development on dev.unified. Merge List: + 2022-08-04 d558507db4 [dev.unified] all: merge master (85d87b9) into dev.unified + 2022-08-03 c9f2150cfb [dev.unified] cmd/compile: start using runtime dictionaries + 2022-07-30 994ff78ba0 [dev.unified] go/internal: set underlying types in proper order + 2022-07-28 23554d4744 [dev.unified] all: merge master (462b78f) into dev.unified + 2022-07-28 c8d5ccf82e [dev.unified] go/internal/gcimporter: flatten imports + 2022-07-28 ac0844ec27 [dev.unified] cmd/compile: move "has init" to private metadata + 2022-07-28 f995946094 [dev.unified] cmd/compile: implement simple inline body pruning heuristic + 2022-07-28 f2851c67fd [dev.unified] cmd/compile: allow inlining to fail gracefully + 2022-07-28 831fdf1dff [dev.unified] cmd/compile: extract nil handling from exprType + 2022-07-28 92798176e7 [dev.unified] cmd/compile: write iface conversion RTTI into unified IR + 2022-07-28 9b70178d58 [dev.unified] cmd/compile: write RTTI into unified IR export data + 2022-07-25 fc72b7705d [dev.unified] cmd/compile: add method expressions to dictionaries + 2022-07-25 f48fa643f1 [dev.unified] cmd/compile: remove obsolete RTTI wiring + 2022-07-22 131f981df0 [dev.unified] cmd/compile: make Unified IR always writes concrete type for const exprs + 2022-07-20 ae43bdc3e3 Merge "[dev.unified] all: merge master (8e1e64c) into dev.unified" into dev.unified + 2022-07-19 7a8ba83b72 [dev.unified] cmd/compile/internal/reflectdata: remove hasRType's `required` param + 2022-07-19 64cd6faa13 [dev.unified] cmd/compile/internal/noder: simplify mixed tag/case RTTI wiring + 2022-07-19 a4c5198a3c [dev.unified] cmd/compile/internal/noder: better switch statements + 2022-07-19 318027044a [dev.unified] cmd/compile/internal/noder: explicit nil handling + 2022-07-19 e971b6a9be [dev.unified] test: add switch test case for tricky nil handling + 2022-07-19 878439cfe5 [dev.unified] cmd/compile/internal/noder: preserve RTTI for select statements + 2022-07-19 e376746e54 [dev.unified] cmd/compile/internal/noder: wire RTTI for implicit conversions + 2022-07-19 c846fd8e13 [dev.unified] cmd/compile/internal/noder: implicit conversions for binary exprs + 2022-07-19 ebd34e3e45 [dev.unified] test: relax panic message expectations + 2022-07-19 76a82f09d6 [dev.unified] cmd/compile/internal/noder: prefer *At functions + 2022-07-19 de649a2a98 [dev.unified] all: merge master (8e1e64c) into dev.unified + 2022-07-19 055a5e55fa [dev.unified] test: change Unicode file/package name to use characters not translated by macOS. + 2022-07-18 2cf632cd57 [dev.unified] cmd/compile/internal/reflectdata: prefer ITabAddrAt in ConvIfaceTypeWord + 2022-07-12 9371a65584 internal/pkgbits: change EnableSync into a dynamic knob + 2022-07-01 d667be8831 [dev.unified] cmd/compile/internal/walk: RType fields for range assignments + 2022-06-30 1b838e9556 [dev.unified] all: merge master (993c387) into dev.unified + 2022-06-30 0a503cf43a [dev.unified] cmd/compile: refactor `range` desugaring + 2022-06-30 3635b07d16 [dev.unified] cmd/compile/internal/noder: implicit conversions for multi-valued expressions + 2022-06-30 e7219cc093 [dev.unified] cmd/compile/internal/noder: refactor N:1 expression handling + 2022-06-30 2f3ef73e18 [dev.unified] test: tweak nilcheck test + 2022-06-30 95d7ce9ab1 [dev.unified] test: break escape_iface.go into unified/nounified variants + 2022-06-30 f751319a0b [dev.unified] test: relax live_regabi.go + 2022-06-30 e3cdc981c8 [dev.unified] cmd/compile/internal/walk: fix typo in debug print + 2022-06-29 2280d897d6 [dev.unified] test: add regress test for generic select statements + 2022-06-27 4b78ece3d7 [dev.unified] cmd/compile: drop package height from Unified IR importer + 2022-06-27 398d46d538 [dev.unified] cmd/compile/internal/types2: remove package height + 2022-06-24 e7100adbca [dev.unified] all: merge master (5a1c5b8) into dev.unified + 2022-06-23 09a838ad86 [dev.unified] cmd/compile: rename haveRType and implicitExpr + 2022-06-23 421e9e9db2 [dev.unified] cmd/compile: implicit conversions for return statements + 2022-06-23 a3fea7796a [dev.unified] cmd/compile/internal/noder: implicit conversions for writer.assignStmt + 2022-06-23 82a958a661 [dev.unified] cmd/compile/internal/noder: refactor stmtAssign generation + 2022-06-23 711dacd8cf [dev.unified] cmd/compile/internal/noder: implicit conversion of call arguments + 2022-06-23 46b01ec667 [dev.unified] cmd/compile/internal/noder: remove needType logic + 2022-06-23 a3e474f867 [dev.unified] cmd/compile/internal/noder: implicit conversions for complits + 2022-06-23 5f5422a2dd [dev.unified] cmd/compile/internal/noder: start writing implicit conversions + 2022-06-23 9cb784ac69 [dev.unified] cmd/compile/internal/noder: add pkgWriter.typeOf helper + 2022-06-23 c70e93ff3d [dev.unified] cmd/compile/internal/typecheck: replace unreachable code with assert + 2022-06-23 20e1d5ac8c [dev.unified] cmd/compile: special case f(g()) calls in Unified IR + 2022-06-23 61ae2b734c [dev.unified] cmd/compile: plumb rtype through OSWITCH/OCASE clauses + 2022-06-23 3d432b6c4b [dev.unified] cmd/compile: plumb rtype through for OMAPLIT + 2022-06-23 7368647ac6 [dev.unified] cmd/compile: start setting RType fields for Unified IR + 2022-06-23 5960f4ec10 [dev.unified] cmd/compile: add RType fields + 2022-06-21 5e0258c700 [dev.unified] cmd/compile: avoid reflectType in ssagen + 2022-06-21 93833cd5d8 [dev.unified] cmd/compile: extract rtype code from walk + 2022-06-21 f70775ff22 [dev.unified] cmd/compile: refactor reflectdata.{TypePtr,ITabAddr} + 2022-06-21 fc5dad6646 [dev.unified] cmd/compile/internal/walk: minor prep refactoring + 2022-06-16 1f4e8afafe [dev.unified] all: merge master (635b124) into dev.unified + 2022-06-15 8a9485c023 [dev.unified] test: extract different inline test between unified and non-unified + 2022-06-14 394ea70cc9 [dev.unified] cmd/compile: more Unified IR docs and review + 2022-06-10 f73ad3d24d [dev.unified] test: add regress tests for #53276 and #53328 + 2022-06-09 8ef8b60e18 [dev.unified] cmd/compile/internal/noder: stop handling type expressions as expressions + 2022-06-09 1a6c96bb9b [dev.unified] test: relax issue7921.go diagnostic message + 2022-06-09 c50c6bbc03 [dev.unified] cmd/compile: set base.Pos when process assignDef in Unified IR + 2022-06-09 d6df08693c [dev.unified] cmd/compile: fix unified IR don't report type size too large error + 2022-06-08 e7ef58542c [dev.unified] cmd/compile: restore Unified IR linkname pragma diagnostic + 2022-06-07 9e5c968021 [dev.unified] cmd/compile: visit LHS before RHS/X in assign/for statement + 2022-06-06 46ddf0873e [dev.unified] cmd/compile: export/import implicit attribute for conversion exprs + 2022-06-06 a8780f94c3 [dev.unified] cmd/compile: fix missing method value wrapper in unified IR + 2022-06-06 3a1f1e1575 [dev.unified] cmd/compile: remove package height + 2022-06-06 df7cb59de4 [dev.unified] cmd/compile: only sort symbols by name and package path + 2022-06-06 b39ac80871 [dev.unified] cmd/compile/internal/noder: push exprBlank up into assignment handling + 2022-06-06 55fc07e164 [dev.unified] cmd/compile/internal/noder: add optExpr for optional expressions + 2022-06-06 6c33f1d52e [dev.unified] cmd/compile/internal/noder: rename exprName to exprGlobal + 2022-06-06 4d28fcabb4 [dev.unified] all: update codereview.cfg for dev.unified branch Change-Id: I604d057735e8a365621c91c206f9e46eabb4679b
2024-09-29 15:14:28 -06:00 · 2022-08-04 10:32:51 -07:00 · 2022-08-04 10:32:51 -07:00 · a10afb15e0
commit a10afb15e0
parent 85d87b9c75 d558507db4
72 changed files with 2709 additions and 674 deletions
--- a/src/cmd/compile/internal/base/flag.go
+++ b/src/cmd/compile/internal/base/flag.go
@ -163,6 +163,7 @@ func ParseFlags() {
 	if buildcfg.Experiment.Unified {
 		Debug.Unified = 1
 	}
+	Debug.SyncFrames = -1 // disable sync markers by default

 	Debug.Checkptr = -1 // so we can tell whether it is set explicitly

--- a/src/cmd/compile/internal/gc/main.go
+++ b/src/cmd/compile/internal/gc/main.go
@ -75,11 +75,6 @@ func Main(archInit func(*ssagen.ArchInfo)) {

 	types.LocalPkg = types.NewPkg(base.Ctxt.Pkgpath, "")

-	// We won't know localpkg's height until after import
-	// processing. In the mean time, set to MaxPkgHeight to ensure
-	// height comparisons at least work until then.
-	types.LocalPkg.Height = types.MaxPkgHeight
-
 	// pseudo-package, for scoping
 	types.BuiltinPkg = types.NewPkg("go.builtin", "") // TODO(gri) name this package go.builtin?
 	types.BuiltinPkg.Prefix = "go.builtin"            // not go%2ebuiltin
--- a/src/cmd/compile/internal/importer/iimport.go
+++ b/src/cmd/compile/internal/importer/iimport.go
@ -139,22 +139,19 @@ func ImportData(imports map[string]*types2.Package, data, path string) (pkg *typ
 		pkgPathOff := r.uint64()
 		pkgPath := p.stringAt(pkgPathOff)
 		pkgName := p.stringAt(r.uint64())
-		pkgHeight := int(r.uint64())
+		_ = int(r.uint64()) // was package height, but not necessary anymore.

 		if pkgPath == "" {
 			pkgPath = path
 		}
 		pkg := imports[pkgPath]
 		if pkg == nil {
-			pkg = types2.NewPackageHeight(pkgPath, pkgName, pkgHeight)
+			pkg = types2.NewPackage(pkgPath, pkgName)
 			imports[pkgPath] = pkg
 		} else {
 			if pkg.Name() != pkgName {
 				errorf("conflicting names %s and %s for package %q", pkg.Name(), pkgName, path)
 			}
-			if pkg.Height() != pkgHeight {
-				errorf("conflicting heights %v and %v for package %q", pkg.Height(), pkgHeight, path)
-			}
 		}

 		p.pkgCache[pkgPathOff] = pkg
--- a/src/cmd/compile/internal/importer/ureader.go
+++ b/src/cmd/compile/internal/importer/ureader.go
@ -39,7 +39,7 @@ func ReadPackage(ctxt *types2.Context, imports map[string]*types2.Package, input

 	r := pr.newReader(pkgbits.RelocMeta, pkgbits.PublicRootIdx, pkgbits.SyncPublic)
 	pkg := r.pkg()
-	r.Bool() // has init
+	r.Bool() // TODO(mdempsky): Remove; was "has init"

 	for i, n := 0, r.Len(); i < n; i++ {
 		// As if r.obj(), but avoiding the Scope.Lookup call,
@ -162,9 +162,7 @@ func (r *reader) doPkg() *types2.Package {
 	}

 	name := r.String()
-	height := r.Len()
-
-	pkg := types2.NewPackageHeight(path, name, height)
+	pkg := types2.NewPackage(path, name)
 	r.p.imports[path] = pkg

 	// TODO(mdempsky): The list of imported packages is important for
--- a/src/cmd/compile/internal/inline/inl.go
+++ b/src/cmd/compile/internal/inline/inl.go
@ -430,6 +430,36 @@ func (v *hairyVisitor) doNode(n ir.Node) bool {

 	case ir.OMETHEXPR:
 		v.budget++ // Hack for toolstash -cmp.
+
+	case ir.OAS2:
+		n := n.(*ir.AssignListStmt)
+
+		// Unified IR unconditionally rewrites:
+		//
+		//	a, b = f()
+		//
+		// into:
+		//
+		//	DCL tmp1
+		//	DCL tmp2
+		//	tmp1, tmp2 = f()
+		//	a, b = tmp1, tmp2
+		//
+		// so that it can insert implicit conversions as necessary. To
+		// minimize impact to the existing inlining heuristics (in
+		// particular, to avoid breaking the existing inlinability regress
+		// tests), we need to compensate for this here.
+		if base.Debug.Unified != 0 {
+			if init := n.Rhs[0].Init(); len(init) == 1 {
+				if _, ok := init[0].(*ir.AssignListStmt); ok {
+					// 4 for each value, because each temporary variable now
+					// appears 3 times (DCL, LHS, RHS), plus an extra DCL node.
+					//
+					// 1 for the extra "tmp1, tmp2 = f()" assignment statement.
+					v.budget += 4*int32(len(n.Lhs)) + 1
+				}
+			}
+		}
 	}

 	v.budget--
@ -655,9 +685,8 @@ var inlgen int
 var SSADumpInline = func(*ir.Func) {}

 // NewInline allows the inliner implementation to be overridden.
-// If it returns nil, the legacy inliner will handle this call
-// instead.
-var NewInline = func(call *ir.CallExpr, fn *ir.Func, inlIndex int) *ir.InlinedCallExpr { return nil }
+// If it returns nil, the function will not be inlined.
+var NewInline = oldInline

 // If n is a OCALLFUNC node, and fn is an ONAME node for a
 // function with an inlinable body, return an OINLCALL node that can replace n.
@ -777,7 +806,7 @@ func mkinlcall(n *ir.CallExpr, fn *ir.Func, maxCost int32, inlMap map[*ir.Func]b

 	res := NewInline(n, fn, inlIndex)
 	if res == nil {
-		res = oldInline(n, fn, inlIndex)
+		return n
 	}

 	// transitive inlining
--- a/src/cmd/compile/internal/ir/expr.go
+++ b/src/cmd/compile/internal/ir/expr.go
@ -119,8 +119,9 @@ func (n *BasicLit) SetVal(val constant.Value) { n.val = val }
 // or Op(X, Y) for builtin functions that do not become calls.
 type BinaryExpr struct {
 	miniExpr
-	X Node
-	Y Node
+	X     Node
+	Y     Node
+	RType Node `mknode:"-"` // see reflectdata/helpers.go
 }

 func NewBinaryExpr(pos src.XPos, op Op, x, y Node) *BinaryExpr {
@ -148,6 +149,7 @@ type CallExpr struct {
 	origNode
 	X         Node
 	Args      Nodes
+	RType     Node    `mknode:"-"` // see reflectdata/helpers.go
 	KeepAlive []*Name // vars to be kept alive until call returns
 	IsDDD     bool
 	NoInline  bool
@ -192,6 +194,7 @@ type CompLitExpr struct {
 	miniExpr
 	origNode
 	List     Nodes // initialized values
+	RType    Node  `mknode:"-"` // *runtime._type for OMAPLIT map types
 	Prealloc *Name
 	// For OSLICELIT, Len is the backing array length.
 	// For OMAPLIT, Len is the number of entries that we've removed from List and
@ -246,6 +249,27 @@ func (n *ConstExpr) Val() constant.Value { return n.val }
 type ConvExpr struct {
 	miniExpr
 	X Node
+
+	// For implementing OCONVIFACE expressions.
+	//
+	// TypeWord is an expression yielding a *runtime._type or
+	// *runtime.itab value to go in the type word of the iface/eface
+	// result. See reflectdata.ConvIfaceTypeWord for further details.
+	//
+	// SrcRType is an expression yielding a *runtime._type value for X,
+	// if it's not pointer-shaped and needs to be heap allocated.
+	TypeWord Node `mknode:"-"`
+	SrcRType Node `mknode:"-"`
+
+	// For -d=checkptr instrumentation of conversions from
+	// unsafe.Pointer to *Elem or *[Len]Elem.
+	//
+	// TODO(mdempsky): We only ever need one of these, but currently we
+	// don't decide which one until walk. Longer term, it probably makes
+	// sense to have a dedicated IR op for `(*[Len]Elem)(ptr)[:n:m]`
+	// expressions.
+	ElemRType     Node `mknode:"-"`
+	ElemElemRType Node `mknode:"-"`
 }

 func NewConvExpr(pos src.XPos, op Op, typ *types.Type, x Node) *ConvExpr {
@ -275,6 +299,7 @@ type IndexExpr struct {
 	miniExpr
 	X        Node
 	Index    Node
+	RType    Node `mknode:"-"` // see reflectdata/helpers.go
 	Assigned bool
 }

@ -385,8 +410,9 @@ func (n *LogicalExpr) SetOp(op Op) {
 // but *not* OMAKE (that's a pre-typechecking CallExpr).
 type MakeExpr struct {
 	miniExpr
-	Len Node
-	Cap Node
+	RType Node `mknode:"-"` // see reflectdata/helpers.go
+	Len   Node
+	Cap   Node
 }

 func NewMakeExpr(pos src.XPos, op Op, len, cap Node) *MakeExpr {
@ -623,7 +649,7 @@ type TypeAssertExpr struct {

 	// Runtime type information provided by walkDotType for
 	// assertions from non-empty interface to concrete type.
-	ITab *AddrExpr `mknode:"-"` // *runtime.itab for Type implementing X's type
+	ITab Node `mknode:"-"` // *runtime.itab for Type implementing X's type
 }

 func NewTypeAssertExpr(pos src.XPos, x Node, typ *types.Type) *TypeAssertExpr {
@ -650,6 +676,11 @@ type DynamicTypeAssertExpr struct {
 	miniExpr
 	X Node

+	// SrcRType is an expression that yields a *runtime._type value
+	// representing X's type. It's used in failed assertion panic
+	// messages.
+	SrcRType Node
+
 	// RType is an expression that yields a *runtime._type value
 	// representing the asserted type.
 	//
--- a/src/cmd/compile/internal/ir/stmt.go
+++ b/src/cmd/compile/internal/ir/stmt.go
@ -170,6 +170,17 @@ type CaseClause struct {
 	miniStmt
 	Var  *Name // declared variable for this case in type switch
 	List Nodes // list of expressions for switch, early select
+
+	// RTypes is a list of RType expressions, which are copied to the
+	// corresponding OEQ nodes that are emitted when switch statements
+	// are desugared. RTypes[i] must be non-nil if the emitted
+	// comparison for List[i] will be a mixed interface/concrete
+	// comparison; see reflectdata.CompareRType for details.
+	//
+	// Because mixed interface/concrete switch cases are rare, we allow
+	// len(RTypes) < len(List). Missing entries are implicitly nil.
+	RTypes Nodes
+
 	Body Nodes
 }

@ -333,11 +344,20 @@ type RangeStmt struct {
 	Label    *types.Sym
 	Def      bool
 	X        Node
+	RType    Node `mknode:"-"` // see reflectdata/helpers.go
 	Key      Node
 	Value    Node
 	Body     Nodes
 	HasBreak bool
 	Prealloc *Name
+
+	// When desugaring the RangeStmt during walk, the assignments to Key
+	// and Value may require OCONVIFACE operations. If so, these fields
+	// will be copied to their respective ConvExpr fields.
+	KeyTypeWord   Node `mknode:"-"`
+	KeySrcRType   Node `mknode:"-"`
+	ValueTypeWord Node `mknode:"-"`
+	ValueSrcRType Node `mknode:"-"`
 }

 func NewRangeStmt(pos src.XPos, key, value, x Node, body []Node) *RangeStmt {
--- a/src/cmd/compile/internal/noder/codes.go
+++ b/src/cmd/compile/internal/noder/codes.go
@ -1,5 +1,3 @@
-// UNREVIEWED
-
 // Copyright 2021 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
@ -8,6 +6,7 @@ package noder

 import "internal/pkgbits"

+// A codeStmt distinguishes among statement encodings.
 type codeStmt int

 func (c codeStmt) Marker() pkgbits.SyncMarker { return pkgbits.SyncStmt1 }
@ -31,6 +30,7 @@ const (
 	stmtSelect
 )

+// A codeExpr distinguishes among expression encodings.
 type codeExpr int

 func (c codeExpr) Marker() pkgbits.SyncMarker { return pkgbits.SyncExpr }
@ -38,12 +38,9 @@ func (c codeExpr) Value() int                 { return int(c) }

 // TODO(mdempsky): Split expr into addr, for lvalues.
 const (
-	exprNone codeExpr = iota
-	exprConst
-	exprType  // type expression
-	exprLocal // local variable
-	exprName  // global variable or function
-	exprBlank
+	exprConst  codeExpr = iota
+	exprLocal           // local variable
+	exprGlobal          // global variable or function
 	exprCompLit
 	exprFuncLit
 	exprSelector
@ -54,8 +51,23 @@ const (
 	exprBinaryOp
 	exprCall
 	exprConvert
+	exprNew
+	exprMake
+	exprNil
 )

+type codeAssign int
+
+func (c codeAssign) Marker() pkgbits.SyncMarker { return pkgbits.SyncAssign }
+func (c codeAssign) Value() int                 { return int(c) }
+
+const (
+	assignBlank codeAssign = iota
+	assignDef
+	assignExpr
+)
+
+// A codeDecl distinguishes among declaration encodings.
 type codeDecl int

 func (c codeDecl) Marker() pkgbits.SyncMarker { return pkgbits.SyncDecl }
--- a/src/cmd/compile/internal/noder/expr.go
+++ b/src/cmd/compile/internal/noder/expr.go
@ -6,7 +6,6 @@ package noder

 import (
 	"fmt"
-	"go/constant"

 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
@ -53,31 +52,9 @@ func (g *irgen) expr(expr syntax.Expr) ir.Node {

 	base.Assert(g.exprStmtOK)

-	// The gc backend expects all expressions to have a concrete type, and
-	// types2 mostly satisfies this expectation already. But there are a few
-	// cases where the Go spec doesn't require converting to concrete type,
-	// and so types2 leaves them untyped. So we need to fix those up here.
-	typ := tv.Type
-	if basic, ok := typ.(*types2.Basic); ok && basic.Info()&types2.IsUntyped != 0 {
-		switch basic.Kind() {
-		case types2.UntypedNil:
-			// ok; can appear in type switch case clauses
-			// TODO(mdempsky): Handle as part of type switches instead?
-		case types2.UntypedInt, types2.UntypedFloat, types2.UntypedComplex:
-			// Untyped rhs of non-constant shift, e.g. x << 1.0.
-			// If we have a constant value, it must be an int >= 0.
-			if tv.Value != nil {
-				s := constant.ToInt(tv.Value)
-				assert(s.Kind() == constant.Int && constant.Sign(s) >= 0)
-			}
-			typ = types2.Typ[types2.Uint]
-		case types2.UntypedBool:
-			typ = types2.Typ[types2.Bool] // expression in "if" or "for" condition
-		case types2.UntypedString:
-			typ = types2.Typ[types2.String] // argument to "append" or "copy" calls
-		default:
-			base.FatalfAt(g.pos(expr), "unexpected untyped type: %v", basic)
-		}
+	typ := idealType(tv)
+	if typ == nil {
+		base.FatalfAt(g.pos(expr), "unexpected untyped type: %v", tv.Type)
 	}

 	// Constant expression.
--- a/src/cmd/compile/internal/noder/helpers.go
+++ b/src/cmd/compile/internal/noder/helpers.go
@ -11,6 +11,7 @@ import (
 	"cmd/compile/internal/ir"
 	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
+	"cmd/compile/internal/types2"
 	"cmd/internal/src"
 )

@ -39,10 +40,6 @@ func typed(typ *types.Type, n ir.Node) ir.Node {

 // Values

-func Const(pos src.XPos, typ *types.Type, val constant.Value) ir.Node {
-	return typed(typ, ir.NewBasicLit(pos, val))
-}
-
 func OrigConst(pos src.XPos, typ *types.Type, val constant.Value, op ir.Op, raw string) ir.Node {
 	orig := ir.NewRawOrigExpr(pos, op, raw)
 	return ir.NewConstExpr(val, typed(typ, orig))
@ -224,3 +221,33 @@ func IncDec(pos src.XPos, op ir.Op, x ir.Node) *ir.AssignOpStmt {
 	}
 	return ir.NewAssignOpStmt(pos, op, x, bl)
 }
+
+func idealType(tv types2.TypeAndValue) types2.Type {
+	// The gc backend expects all expressions to have a concrete type, and
+	// types2 mostly satisfies this expectation already. But there are a few
+	// cases where the Go spec doesn't require converting to concrete type,
+	// and so types2 leaves them untyped. So we need to fix those up here.
+	typ := tv.Type
+	if basic, ok := typ.(*types2.Basic); ok && basic.Info()&types2.IsUntyped != 0 {
+		switch basic.Kind() {
+		case types2.UntypedNil:
+			// ok; can appear in type switch case clauses
+			// TODO(mdempsky): Handle as part of type switches instead?
+		case types2.UntypedInt, types2.UntypedFloat, types2.UntypedComplex:
+			// Untyped rhs of non-constant shift, e.g. x << 1.0.
+			// If we have a constant value, it must be an int >= 0.
+			if tv.Value != nil {
+				s := constant.ToInt(tv.Value)
+				assert(s.Kind() == constant.Int && constant.Sign(s) >= 0)
+			}
+			typ = types2.Typ[types2.Uint]
+		case types2.UntypedBool:
+			typ = types2.Typ[types2.Bool] // expression in "if" or "for" condition
+		case types2.UntypedString:
+			typ = types2.Typ[types2.String] // argument to "append" or "copy" calls
+		default:
+			return nil
+		}
+	}
+	return typ
+}
--- a/src/cmd/compile/internal/noder/import.go
+++ b/src/cmd/compile/internal/noder/import.go
@ -241,7 +241,7 @@ func readImportFile(path string, target *ir.Package, env *types2.Context, packag
 		pr := pkgbits.NewPkgDecoder(pkg1.Path, data)

 		// Read package descriptors for both types2 and compiler backend.
-		readPackage(newPkgReader(pr), pkg1)
+		readPackage(newPkgReader(pr), pkg1, false)
 		pkg2 = importer.ReadPackage(env, packages, pr)

 	case 'i':
--- a/src/cmd/compile/internal/noder/irgen.go
+++ b/src/cmd/compile/internal/noder/irgen.go
@ -219,7 +219,6 @@ type typeDelayInfo struct {

 func (g *irgen) generate(noders []*noder) {
 	types.LocalPkg.Name = g.self.Name()
-	types.LocalPkg.Height = g.self.Height()
 	typecheck.TypecheckAllowed = true

 	// Prevent size calculations until we set the underlying type
--- a/src/cmd/compile/internal/noder/linker.go
+++ b/src/cmd/compile/internal/noder/linker.go
@ -1,5 +1,3 @@
-// UNREVIEWED
-
 // Copyright 2021 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
@ -34,13 +32,20 @@ import (
 // low-level linking details can be moved there, but the logic for
 // handling extension data needs to stay in the compiler.

+// A linker combines a package's stub export data with any referenced
+// elements from imported packages into a single, self-contained
+// export data file.
 type linker struct {
 	pw pkgbits.PkgEncoder

-	pkgs  map[string]pkgbits.Index
-	decls map[*types.Sym]pkgbits.Index
+	pkgs   map[string]pkgbits.Index
+	decls  map[*types.Sym]pkgbits.Index
+	bodies map[*types.Sym]pkgbits.Index
 }

+// relocAll ensures that all elements specified by pr and relocs are
+// copied into the output export data file, and returns the
+// corresponding indices in the output.
 func (l *linker) relocAll(pr *pkgReader, relocs []pkgbits.RelocEnt) []pkgbits.RelocEnt {
 	res := make([]pkgbits.RelocEnt, len(relocs))
 	for i, rent := range relocs {
@ -50,6 +55,8 @@ func (l *linker) relocAll(pr *pkgReader, relocs []pkgbits.RelocEnt) []pkgbits.Re
 	return res
 }

+// relocIdx ensures a single element is copied into the output export
+// data file, and returns the corresponding index in the output.
 func (l *linker) relocIdx(pr *pkgReader, k pkgbits.RelocKind, idx pkgbits.Index) pkgbits.Index {
 	assert(pr != nil)

@ -85,10 +92,19 @@ func (l *linker) relocIdx(pr *pkgReader, k pkgbits.RelocKind, idx pkgbits.Index)
 	return newidx
 }

+// relocString copies the specified string from pr into the output
+// export data file, deduplicating it against other strings.
 func (l *linker) relocString(pr *pkgReader, idx pkgbits.Index) pkgbits.Index {
 	return l.pw.StringIdx(pr.StringIdx(idx))
 }

+// relocPkg copies the specified package from pr into the output
+// export data file, rewriting its import path to match how it was
+// imported.
+//
+// TODO(mdempsky): Since CL 391014, we already have the compilation
+// unit's import path, so there should be no need to rewrite packages
+// anymore.
 func (l *linker) relocPkg(pr *pkgReader, idx pkgbits.Index) pkgbits.Index {
 	path := pr.PeekPkgPath(idx)

@ -114,6 +130,9 @@ func (l *linker) relocPkg(pr *pkgReader, idx pkgbits.Index) pkgbits.Index {
 	return w.Flush()
 }

+// relocObj copies the specified object from pr into the output export
+// data file, rewriting its compiler-private extension data (e.g.,
+// adding inlining cost and escape analysis results for functions).
 func (l *linker) relocObj(pr *pkgReader, idx pkgbits.Index) pkgbits.Index {
 	path, name, tag := pr.PeekObj(idx)
 	sym := types.NewPkg(path, "").Lookup(name)
@ -152,21 +171,12 @@ func (l *linker) relocObj(pr *pkgReader, idx pkgbits.Index) pkgbits.Index {
 	l.relocCommon(pr, &wname, pkgbits.RelocName, idx)
 	l.relocCommon(pr, &wdict, pkgbits.RelocObjDict, idx)

-	var obj *ir.Name
-	if sym.Pkg == types.LocalPkg {
-		var ok bool
-		obj, ok = sym.Def.(*ir.Name)
+	// Generic types and functions won't have definitions, and imported
+	// objects may not either.
+	obj, _ := sym.Def.(*ir.Name)
+	local := sym.Pkg == types.LocalPkg

-		// Generic types and functions and declared constraint types won't
-		// have definitions.
-		// For now, just generically copy their extension data.
-		// TODO(mdempsky): Restore assertion.
-		if !ok && false {
-			base.Fatalf("missing definition for %v", sym)
-		}
-	}
-
-	if obj != nil {
+	if local && obj != nil {
 		wext.Sync(pkgbits.SyncObject1)
 		switch tag {
 		case pkgbits.ObjFunc:
@ -181,9 +191,66 @@ func (l *linker) relocObj(pr *pkgReader, idx pkgbits.Index) pkgbits.Index {
 		l.relocCommon(pr, &wext, pkgbits.RelocObjExt, idx)
 	}

+	// Check if we need to export the inline bodies for functions and
+	// methods.
+	if obj != nil {
+		if obj.Op() == ir.ONAME && obj.Class == ir.PFUNC {
+			l.exportBody(obj, local)
+		}
+
+		if obj.Op() == ir.OTYPE {
+			if typ := obj.Type(); !typ.IsInterface() {
+				for _, method := range typ.Methods().Slice() {
+					l.exportBody(method.Nname.(*ir.Name), local)
+				}
+			}
+		}
+	}
+
 	return w.Idx
 }

+// exportBody exports the given function or method's body, if
+// appropriate. local indicates whether it's a local function or
+// method available on a locally declared type. (Due to cross-package
+// type aliases, a method may be imported, but still available on a
+// locally declared type.)
+func (l *linker) exportBody(obj *ir.Name, local bool) {
+	assert(obj.Op() == ir.ONAME && obj.Class == ir.PFUNC)
+
+	fn := obj.Func
+	if fn.Inl == nil {
+		return // not inlinable anyway
+	}
+
+	// As a simple heuristic, if the function was declared in this
+	// package or we inlined it somewhere in this package, then we'll
+	// (re)export the function body. This isn't perfect, but seems
+	// reasonable in practice. In particular, it has the nice property
+	// that in the worst case, adding a blank import ensures the
+	// function body is available for inlining.
+	//
+	// TODO(mdempsky): Reimplement the reachable method crawling logic
+	// from typecheck/crawler.go.
+	exportBody := local || fn.Inl.Body != nil
+	if !exportBody {
+		return
+	}
+
+	sym := obj.Sym()
+	if _, ok := l.bodies[sym]; ok {
+		// Due to type aliases, we might visit methods multiple times.
+		base.AssertfAt(obj.Type().Recv() != nil, obj.Pos(), "expected method: %v", obj)
+		return
+	}
+
+	pri, ok := bodyReaderFor(fn)
+	assert(ok)
+	l.bodies[sym] = l.relocIdx(pri.pr, pkgbits.RelocBody, pri.idx)
+}
+
+// relocCommon copies the specified element from pr into w,
+// recursively relocating any referenced elements as well.
 func (l *linker) relocCommon(pr *pkgReader, w *pkgbits.Encoder, k pkgbits.RelocKind, idx pkgbits.Index) {
 	r := pr.NewDecoderRaw(k, idx)
 	w.Relocs = l.relocAll(pr, r.Relocs)
@ -220,10 +287,6 @@ func (l *linker) relocFuncExt(w *pkgbits.Encoder, name *ir.Name) {
 	if inl := name.Func.Inl; w.Bool(inl != nil) {
 		w.Len(int(inl.Cost))
 		w.Bool(inl.CanDelayResults)
-
-		pri, ok := bodyReader[name.Func]
-		assert(ok)
-		w.Reloc(pkgbits.RelocBody, l.relocIdx(pri.pr, pkgbits.RelocBody, pri.idx))
 	}

 	w.Sync(pkgbits.SyncEOF)
--- a/src/cmd/compile/internal/noder/quirks.go
+++ b/src/cmd/compile/internal/noder/quirks.go
@ -1,5 +1,3 @@
-// UNREVIEWED
-
 // Copyright 2021 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
@ -12,12 +10,12 @@ import (
 	"cmd/compile/internal/syntax"
 )

-// This file defines helper functions useful for satisfying toolstash
-// -cmp when compared against the legacy frontend behavior, but can be
-// removed after that's no longer a concern.
-
 // typeExprEndPos returns the position that noder would leave base.Pos
 // after parsing the given type expression.
+//
+// Deprecated: This function exists to emulate position semantics from
+// Go 1.17, necessary for compatibility with the backend DWARF
+// generation logic that assigns variables to their appropriate scope.
 func typeExprEndPos(expr0 syntax.Expr) syntax.Pos {
 	for {
 		switch expr := expr0.(type) {
--- a/src/cmd/compile/internal/noder/reader.go
+++ b/src/cmd/compile/internal/noder/reader.go
--- a/src/cmd/compile/internal/noder/unified.go
+++ b/src/cmd/compile/internal/noder/unified.go
@ -1,5 +1,3 @@
-// UNREVIEWED
-
 // Copyright 2021 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
@ -82,13 +80,12 @@ func unified(noders []*noder) {
 	base.Flag.Lang = fmt.Sprintf("go1.%d", goversion.Version)
 	types.ParseLangFlag()

-	types.LocalPkg.Height = 0 // reset so pkgReader.pkgIdx doesn't complain
 	target := typecheck.Target

 	typecheck.TypecheckAllowed = true

 	localPkgReader = newPkgReader(pkgbits.NewPkgDecoder(types.LocalPkg.Path, data))
-	readPackage(localPkgReader, types.LocalPkg)
+	readPackage(localPkgReader, types.LocalPkg, true)

 	r := localPkgReader.newReader(pkgbits.RelocMeta, pkgbits.PrivateRootIdx, pkgbits.SyncPrivate)
 	r.pkgInit(types.LocalPkg, target)
@ -164,7 +161,7 @@ func writePkgStub(noders []*noder) string {
 	{
 		w := publicRootWriter
 		w.pkg(pkg)
-		w.Bool(false) // has init; XXX
+		w.Bool(false) // TODO(mdempsky): Remove; was "has init"

 		scope := pkg.Scope()
 		names := scope.Names()
@ -227,42 +224,76 @@ func freePackage(pkg *types2.Package) {
 	base.Fatalf("package never finalized")
 }

-func readPackage(pr *pkgReader, importpkg *types.Pkg) {
-	r := pr.newReader(pkgbits.RelocMeta, pkgbits.PublicRootIdx, pkgbits.SyncPublic)
+// readPackage reads package export data from pr to populate
+// importpkg.
+//
+// localStub indicates whether pr is reading the stub export data for
+// the local package, as opposed to relocated export data for an
+// import.
+func readPackage(pr *pkgReader, importpkg *types.Pkg, localStub bool) {
+	{
+		r := pr.newReader(pkgbits.RelocMeta, pkgbits.PublicRootIdx, pkgbits.SyncPublic)

-	pkg := r.pkg()
-	base.Assertf(pkg == importpkg, "have package %q (%p), want package %q (%p)", pkg.Path, pkg, importpkg.Path, importpkg)
+		pkg := r.pkg()
+		base.Assertf(pkg == importpkg, "have package %q (%p), want package %q (%p)", pkg.Path, pkg, importpkg.Path, importpkg)

-	if r.Bool() {
-		sym := pkg.Lookup(".inittask")
-		task := ir.NewNameAt(src.NoXPos, sym)
-		task.Class = ir.PEXTERN
-		sym.Def = task
+		r.Bool() // TODO(mdempsky): Remove; was "has init"
+
+		for i, n := 0, r.Len(); i < n; i++ {
+			r.Sync(pkgbits.SyncObject)
+			assert(!r.Bool())
+			idx := r.Reloc(pkgbits.RelocObj)
+			assert(r.Len() == 0)
+
+			path, name, code := r.p.PeekObj(idx)
+			if code != pkgbits.ObjStub {
+				objReader[types.NewPkg(path, "").Lookup(name)] = pkgReaderIndex{pr, idx, nil, nil}
+			}
+		}
+
+		r.Sync(pkgbits.SyncEOF)
 	}

-	for i, n := 0, r.Len(); i < n; i++ {
-		r.Sync(pkgbits.SyncObject)
-		assert(!r.Bool())
-		idx := r.Reloc(pkgbits.RelocObj)
-		assert(r.Len() == 0)
+	if !localStub {
+		r := pr.newReader(pkgbits.RelocMeta, pkgbits.PrivateRootIdx, pkgbits.SyncPrivate)

-		path, name, code := r.p.PeekObj(idx)
-		if code != pkgbits.ObjStub {
-			objReader[types.NewPkg(path, "").Lookup(name)] = pkgReaderIndex{pr, idx, nil}
+		if r.Bool() {
+			sym := importpkg.Lookup(".inittask")
+			task := ir.NewNameAt(src.NoXPos, sym)
+			task.Class = ir.PEXTERN
+			sym.Def = task
 		}
+
+		for i, n := 0, r.Len(); i < n; i++ {
+			path := r.String()
+			name := r.String()
+			idx := r.Reloc(pkgbits.RelocBody)
+
+			sym := types.NewPkg(path, "").Lookup(name)
+			if _, ok := importBodyReader[sym]; !ok {
+				importBodyReader[sym] = pkgReaderIndex{pr, idx, nil, nil}
+			}
+		}
+
+		r.Sync(pkgbits.SyncEOF)
 	}
 }

+// writeUnifiedExport writes to `out` the finalized, self-contained
+// Unified IR export data file for the current compilation unit.
 func writeUnifiedExport(out io.Writer) {
 	l := linker{
 		pw: pkgbits.NewPkgEncoder(base.Debug.SyncFrames),

-		pkgs:  make(map[string]pkgbits.Index),
-		decls: make(map[*types.Sym]pkgbits.Index),
+		pkgs:   make(map[string]pkgbits.Index),
+		decls:  make(map[*types.Sym]pkgbits.Index),
+		bodies: make(map[*types.Sym]pkgbits.Index),
 	}

 	publicRootWriter := l.pw.NewEncoder(pkgbits.RelocMeta, pkgbits.SyncPublic)
+	privateRootWriter := l.pw.NewEncoder(pkgbits.RelocMeta, pkgbits.SyncPrivate)
 	assert(publicRootWriter.Idx == pkgbits.PublicRootIdx)
+	assert(privateRootWriter.Idx == pkgbits.PrivateRootIdx)

 	var selfPkgIdx pkgbits.Index

@ -273,7 +304,7 @@ func writeUnifiedExport(out io.Writer) {
 		r.Sync(pkgbits.SyncPkg)
 		selfPkgIdx = l.relocIdx(pr, pkgbits.RelocPkg, r.Reloc(pkgbits.RelocPkg))

-		r.Bool() // has init
+		r.Bool() // TODO(mdempsky): Remove; was "has init"

 		for i, n := 0, r.Len(); i < n; i++ {
 			r.Sync(pkgbits.SyncObject)
@ -304,8 +335,7 @@ func writeUnifiedExport(out io.Writer) {

 		w.Sync(pkgbits.SyncPkg)
 		w.Reloc(pkgbits.RelocPkg, selfPkgIdx)
-
-		w.Bool(typecheck.Lookup(".inittask").Def != nil)
+		w.Bool(false) // TODO(mdempsky): Remove; was "has init"

 		w.Len(len(idxs))
 		for _, idx := range idxs {
@ -319,5 +349,31 @@ func writeUnifiedExport(out io.Writer) {
 		w.Flush()
 	}

+	{
+		type symIdx struct {
+			sym *types.Sym
+			idx pkgbits.Index
+		}
+		var bodies []symIdx
+		for sym, idx := range l.bodies {
+			bodies = append(bodies, symIdx{sym, idx})
+		}
+		sort.Slice(bodies, func(i, j int) bool { return bodies[i].idx < bodies[j].idx })
+
+		w := privateRootWriter
+
+		w.Bool(typecheck.Lookup(".inittask").Def != nil)
+
+		w.Len(len(bodies))
+		for _, body := range bodies {
+			w.String(body.sym.Pkg.Path)
+			w.String(body.sym.Name)
+			w.Reloc(pkgbits.RelocBody, body.idx)
+		}
+
+		w.Sync(pkgbits.SyncEOF)
+		w.Flush()
+	}
+
 	base.Ctxt.Fingerprint = l.pw.DumpTo(out)
 }
--- a/src/cmd/compile/internal/noder/writer.go
+++ b/src/cmd/compile/internal/noder/writer.go
--- a/src/cmd/compile/internal/reflectdata/helpers.go
+++ b/src/cmd/compile/internal/reflectdata/helpers.go
@ -0,0 +1,226 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package reflectdata
+
+import (
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/types"
+	"cmd/internal/src"
+)
+
+func hasRType(n, rtype ir.Node, fieldName string) bool {
+	if rtype != nil {
+		return true
+	}
+
+	// We make an exception for `init`, because we still depend on
+	// pkginit for sorting package initialization statements, and it
+	// gets confused by implicit conversions. Also, because
+	// package-scope statements can never be generic, so they'll never
+	// require dictionary lookups.
+	if base.Debug.Unified != 0 && ir.CurFunc.Nname.Sym().Name != "init" {
+		ir.Dump("CurFunc", ir.CurFunc)
+		base.FatalfAt(n.Pos(), "missing %s in %v: %+v", fieldName, ir.CurFunc, n)
+	}
+
+	return false
+}
+
+// assertOp asserts that n is an op.
+func assertOp(n ir.Node, op ir.Op) {
+	base.AssertfAt(n.Op() == op, n.Pos(), "want %v, have %v", op, n)
+}
+
+// assertOp2 asserts that n is an op1 or op2.
+func assertOp2(n ir.Node, op1, op2 ir.Op) {
+	base.AssertfAt(n.Op() == op1 || n.Op() == op2, n.Pos(), "want %v or %v, have %v", op1, op2, n)
+}
+
+// kindRType asserts that typ has the given kind, and returns an
+// expression that yields the *runtime._type value representing typ.
+func kindRType(pos src.XPos, typ *types.Type, k types.Kind) ir.Node {
+	base.AssertfAt(typ.Kind() == k, pos, "want %v type, have %v", k, typ)
+	return TypePtrAt(pos, typ)
+}
+
+// mapRType asserts that typ is a map type, and returns an expression
+// that yields the *runtime._type value representing typ.
+func mapRType(pos src.XPos, typ *types.Type) ir.Node {
+	return kindRType(pos, typ, types.TMAP)
+}
+
+// chanRType asserts that typ is a map type, and returns an expression
+// that yields the *runtime._type value representing typ.
+func chanRType(pos src.XPos, typ *types.Type) ir.Node {
+	return kindRType(pos, typ, types.TCHAN)
+}
+
+// sliceElemRType asserts that typ is a slice type, and returns an
+// expression that yields the *runtime._type value representing typ's
+// element type.
+func sliceElemRType(pos src.XPos, typ *types.Type) ir.Node {
+	base.AssertfAt(typ.IsSlice(), pos, "want slice type, have %v", typ)
+	return TypePtrAt(pos, typ.Elem())
+}
+
+// concreteRType asserts that typ is not an interface type, and
+// returns an expression that yields the *runtime._type value
+// representing typ.
+func concreteRType(pos src.XPos, typ *types.Type) ir.Node {
+	base.AssertfAt(!typ.IsInterface(), pos, "want non-interface type, have %v", typ)
+	return TypePtrAt(pos, typ)
+}
+
+// AppendElemRType asserts that n is an "append" operation, and
+// returns an expression that yields the *runtime._type value
+// representing the result slice type's element type.
+func AppendElemRType(pos src.XPos, n *ir.CallExpr) ir.Node {
+	assertOp(n, ir.OAPPEND)
+	if hasRType(n, n.RType, "RType") {
+		return n.RType
+	}
+	return sliceElemRType(pos, n.Type())
+}
+
+// CompareRType asserts that n is a comparison (== or !=) operation
+// between expressions of interface and non-interface type, and
+// returns an expression that yields the *runtime._type value
+// representing the non-interface type.
+func CompareRType(pos src.XPos, n *ir.BinaryExpr) ir.Node {
+	assertOp2(n, ir.OEQ, ir.ONE)
+	base.AssertfAt(n.X.Type().IsInterface() != n.Y.Type().IsInterface(), n.Pos(), "expect mixed interface and non-interface, have %L and %L", n.X, n.Y)
+	if hasRType(n, n.RType, "RType") {
+		return n.RType
+	}
+	typ := n.X.Type()
+	if typ.IsInterface() {
+		typ = n.Y.Type()
+	}
+	return concreteRType(pos, typ)
+}
+
+// ConvIfaceTypeWord asserts that n is conversion to interface type,
+// and returns an expression that yields the *runtime._type or
+// *runtime.itab value necessary for implementing the conversion.
+//
+//   - *runtime._type for the destination type, for I2I conversions
+//   - *runtime.itab, for T2I conversions
+//   - *runtime._type for the source type, for T2E conversions
+func ConvIfaceTypeWord(pos src.XPos, n *ir.ConvExpr) ir.Node {
+	assertOp(n, ir.OCONVIFACE)
+	src, dst := n.X.Type(), n.Type()
+	base.AssertfAt(dst.IsInterface(), n.Pos(), "want interface type, have %L", n)
+	if hasRType(n, n.TypeWord, "TypeWord") {
+		return n.TypeWord
+	}
+	if dst.IsEmptyInterface() {
+		return concreteRType(pos, src) // direct eface construction
+	}
+	if !src.IsInterface() {
+		return ITabAddrAt(pos, src, dst) // direct iface construction
+	}
+	return TypePtrAt(pos, dst) // convI2I
+}
+
+// ConvIfaceSrcRType asserts that n is a conversion from
+// non-interface type to interface type (or OCONVIDATA operation), and
+// returns an expression that yields the *runtime._type for copying
+// the convertee value to the heap.
+func ConvIfaceSrcRType(pos src.XPos, n *ir.ConvExpr) ir.Node {
+	assertOp2(n, ir.OCONVIFACE, ir.OCONVIDATA)
+	if hasRType(n, n.SrcRType, "SrcRType") {
+		return n.SrcRType
+	}
+	return concreteRType(pos, n.X.Type())
+}
+
+// CopyElemRType asserts that n is a "copy" operation, and returns an
+// expression that yields the *runtime._type value representing the
+// destination slice type's element type.
+func CopyElemRType(pos src.XPos, n *ir.BinaryExpr) ir.Node {
+	assertOp(n, ir.OCOPY)
+	if hasRType(n, n.RType, "RType") {
+		return n.RType
+	}
+	return sliceElemRType(pos, n.X.Type())
+}
+
+// DeleteMapRType asserts that n is a "delete" operation, and returns
+// an expression that yields the *runtime._type value representing the
+// map type.
+func DeleteMapRType(pos src.XPos, n *ir.CallExpr) ir.Node {
+	assertOp(n, ir.ODELETE)
+	if hasRType(n, n.RType, "RType") {
+		return n.RType
+	}
+	return mapRType(pos, n.Args[0].Type())
+}
+
+// IndexMapRType asserts that n is a map index operation, and returns
+// an expression that yields the *runtime._type value representing the
+// map type.
+func IndexMapRType(pos src.XPos, n *ir.IndexExpr) ir.Node {
+	assertOp(n, ir.OINDEXMAP)
+	if hasRType(n, n.RType, "RType") {
+		return n.RType
+	}
+	return mapRType(pos, n.X.Type())
+}
+
+// MakeChanRType asserts that n is a "make" operation for a channel
+// type, and returns an expression that yields the *runtime._type
+// value representing that channel type.
+func MakeChanRType(pos src.XPos, n *ir.MakeExpr) ir.Node {
+	assertOp(n, ir.OMAKECHAN)
+	if hasRType(n, n.RType, "RType") {
+		return n.RType
+	}
+	return chanRType(pos, n.Type())
+}
+
+// MakeMapRType asserts that n is a "make" operation for a map type,
+// and returns an expression that yields the *runtime._type value
+// representing that map type.
+func MakeMapRType(pos src.XPos, n *ir.MakeExpr) ir.Node {
+	assertOp(n, ir.OMAKEMAP)
+	if hasRType(n, n.RType, "RType") {
+		return n.RType
+	}
+	return mapRType(pos, n.Type())
+}
+
+// MakeSliceElemRType asserts that n is a "make" operation for a slice
+// type, and returns an expression that yields the *runtime._type
+// value representing that slice type's element type.
+func MakeSliceElemRType(pos src.XPos, n *ir.MakeExpr) ir.Node {
+	assertOp2(n, ir.OMAKESLICE, ir.OMAKESLICECOPY)
+	if hasRType(n, n.RType, "RType") {
+		return n.RType
+	}
+	return sliceElemRType(pos, n.Type())
+}
+
+// RangeMapRType asserts that n is a "range" loop over a map value,
+// and returns an expression that yields the *runtime._type value
+// representing that map type.
+func RangeMapRType(pos src.XPos, n *ir.RangeStmt) ir.Node {
+	assertOp(n, ir.ORANGE)
+	if hasRType(n, n.RType, "RType") {
+		return n.RType
+	}
+	return mapRType(pos, n.X.Type())
+}
+
+// UnsafeSliceElemRType asserts that n is an "unsafe.Slice" operation,
+// and returns an expression that yields the *runtime._type value
+// representing the result slice type's element type.
+func UnsafeSliceElemRType(pos src.XPos, n *ir.BinaryExpr) ir.Node {
+	assertOp(n, ir.OUNSAFESLICE)
+	if hasRType(n, n.RType, "RType") {
+		return n.RType
+	}
+	return sliceElemRType(pos, n.Type())
+}
--- a/src/cmd/compile/internal/reflectdata/reflect.go
+++ b/src/cmd/compile/internal/reflectdata/reflect.go
@ -842,9 +842,15 @@ func TypeLinksym(t *types.Type) *obj.LSym {
 	return TypeSym(t).Linksym()
 }

+// Deprecated: Use TypePtrAt instead.
 func TypePtr(t *types.Type) *ir.AddrExpr {
-	n := ir.NewLinksymExpr(base.Pos, TypeLinksym(t), types.Types[types.TUINT8])
-	return typecheck.Expr(typecheck.NodAddr(n)).(*ir.AddrExpr)
+	return TypePtrAt(base.Pos, t)
+}
+
+// TypePtrAt returns an expression that evaluates to the
+// *runtime._type value for t.
+func TypePtrAt(pos src.XPos, t *types.Type) *ir.AddrExpr {
+	return typecheck.LinksymAddr(pos, TypeLinksym(t), types.Types[types.TUINT8])
 }

 // ITabLsym returns the LSym representing the itab for concrete type typ implementing
@ -864,9 +870,15 @@ func ITabLsym(typ, iface *types.Type) *obj.LSym {
 	return lsym
 }

-// ITabAddr returns an expression representing a pointer to the itab
-// for concrete type typ implementing interface iface.
+// Deprecated: Use ITabAddrAt instead.
 func ITabAddr(typ, iface *types.Type) *ir.AddrExpr {
+	return ITabAddrAt(base.Pos, typ, iface)
+}
+
+// ITabAddrAt returns an expression that evaluates to the
+// *runtime.itab value for concrete type typ implementing interface
+// iface.
+func ITabAddrAt(pos src.XPos, typ, iface *types.Type) *ir.AddrExpr {
 	s, existed := ir.Pkgs.Itab.LookupOK(typ.LinkString() + "," + iface.LinkString())
 	lsym := s.Linksym()

@ -874,8 +886,7 @@ func ITabAddr(typ, iface *types.Type) *ir.AddrExpr {
 		writeITab(lsym, typ, iface, false)
 	}

-	n := ir.NewLinksymExpr(base.Pos, lsym, types.Types[types.TUINT8])
-	return typecheck.Expr(typecheck.NodAddr(n)).(*ir.AddrExpr)
+	return typecheck.LinksymAddr(pos, lsym, types.Types[types.TUINT8])
 }

 // needkeyupdate reports whether map updates with t as a key
--- a/src/cmd/compile/internal/ssa/debug_lines_test.go
+++ b/src/cmd/compile/internal/ssa/debug_lines_test.go
@ -76,7 +76,7 @@ func TestDebugLinesPushback(t *testing.T) {
 		fn := "(*List[go.shape.int_0]).PushBack"
 		if buildcfg.Experiment.Unified {
 			// Unified mangles differently
-			fn = "(*List[int]).PushBack"
+			fn = "(*List[int]).PushBack-shaped"
 		}
 		testDebugLines(t, "-N -l", "pushback.go", fn, []int{17, 18, 19, 20, 21, 22, 24}, true)
 	}
@ -95,7 +95,7 @@ func TestDebugLinesConvert(t *testing.T) {
 		fn := "G[go.shape.int_0]"
 		if buildcfg.Experiment.Unified {
 			// Unified mangles differently
-			fn = "G[int]"
+			fn = "G[int]-shaped"
 		}
 		testDebugLines(t, "-N -l", "convertline.go", fn, []int{9, 10, 11}, true)
 	}
--- a/src/cmd/compile/internal/ssagen/ssa.go
+++ b/src/cmd/compile/internal/ssagen/ssa.go
@ -664,7 +664,7 @@ func (s *state) paramsToHeap() {

 // newHeapaddr allocates heap memory for n and sets its heap address.
 func (s *state) newHeapaddr(n *ir.Name) {
-	s.setHeapaddr(n.Pos(), n, s.newObject(n.Type()))
+	s.setHeapaddr(n.Pos(), n, s.newObject(n.Type(), nil))
 }

 // setHeapaddr allocates a new PAUTO variable to store ptr (which must be non-nil)
@ -692,23 +692,26 @@ func (s *state) setHeapaddr(pos src.XPos, n *ir.Name, ptr *ssa.Value) {
 }

 // newObject returns an SSA value denoting new(typ).
-func (s *state) newObject(typ *types.Type) *ssa.Value {
+func (s *state) newObject(typ *types.Type, rtype *ssa.Value) *ssa.Value {
 	if typ.Size() == 0 {
 		return s.newValue1A(ssa.OpAddr, types.NewPtr(typ), ir.Syms.Zerobase, s.sb)
 	}
-	return s.rtcall(ir.Syms.Newobject, true, []*types.Type{types.NewPtr(typ)}, s.reflectType(typ))[0]
+	if rtype == nil {
+		rtype = s.reflectType(typ)
+	}
+	return s.rtcall(ir.Syms.Newobject, true, []*types.Type{types.NewPtr(typ)}, rtype)[0]
 }

 func (s *state) checkPtrAlignment(n *ir.ConvExpr, v *ssa.Value, count *ssa.Value) {
 	if !n.Type().IsPtr() {
 		s.Fatalf("expected pointer type: %v", n.Type())
 	}
-	elem := n.Type().Elem()
+	elem, rtypeExpr := n.Type().Elem(), n.ElemRType
 	if count != nil {
 		if !elem.IsArray() {
 			s.Fatalf("expected array type: %v", elem)
 		}
-		elem = elem.Elem()
+		elem, rtypeExpr = elem.Elem(), n.ElemElemRType
 	}
 	size := elem.Size()
 	// Casting from larger type to smaller one is ok, so for smallest type, do nothing.
@ -721,12 +724,20 @@ func (s *state) checkPtrAlignment(n *ir.ConvExpr, v *ssa.Value, count *ssa.Value
 	if count.Type.Size() != s.config.PtrSize {
 		s.Fatalf("expected count fit to an uintptr size, have: %d, want: %d", count.Type.Size(), s.config.PtrSize)
 	}
-	s.rtcall(ir.Syms.CheckPtrAlignment, true, nil, v, s.reflectType(elem), count)
+	var rtype *ssa.Value
+	if rtypeExpr != nil {
+		rtype = s.expr(rtypeExpr)
+	} else {
+		rtype = s.reflectType(elem)
+	}
+	s.rtcall(ir.Syms.CheckPtrAlignment, true, nil, v, rtype, count)
 }

 // reflectType returns an SSA value representing a pointer to typ's
 // reflection type descriptor.
 func (s *state) reflectType(typ *types.Type) *ssa.Value {
+	// TODO(mdempsky): Make this Fatalf under Unified IR; frontend needs
+	// to supply RType expressions.
 	lsym := reflectdata.TypeLinksym(typ)
 	return s.entryNewValue1A(ssa.OpAddr, types.NewPtr(types.Types[types.TUINT8]), lsym, s.sb)
 }
@ -3294,7 +3305,11 @@ func (s *state) exprCheckPtr(n ir.Node, checkPtrOK bool) *ssa.Value {

 	case ir.ONEW:
 		n := n.(*ir.UnaryExpr)
-		return s.newObject(n.Type().Elem())
+		var rtype *ssa.Value
+		if x, ok := n.X.(*ir.DynamicType); ok && x.Op() == ir.ODYNAMICTYPE {
+			rtype = s.expr(x.RType)
+		}
+		return s.newObject(n.Type().Elem(), rtype)

 	case ir.OUNSAFEADD:
 		n := n.(*ir.BinaryExpr)
@ -6226,12 +6241,15 @@ func (s *state) dottype(n *ir.TypeAssertExpr, commaok bool) (res, resok *ssa.Val
 	if n.ITab != nil {
 		targetItab = s.expr(n.ITab)
 	}
-	return s.dottype1(n.Pos(), n.X.Type(), n.Type(), iface, target, targetItab, commaok)
+	return s.dottype1(n.Pos(), n.X.Type(), n.Type(), iface, nil, target, targetItab, commaok)
 }

 func (s *state) dynamicDottype(n *ir.DynamicTypeAssertExpr, commaok bool) (res, resok *ssa.Value) {
 	iface := s.expr(n.X)
-	var target, targetItab *ssa.Value
+	var source, target, targetItab *ssa.Value
+	if n.SrcRType != nil {
+		source = s.expr(n.SrcRType)
+	}
 	if !n.X.Type().IsEmptyInterface() && !n.Type().IsInterface() {
 		byteptr := s.f.Config.Types.BytePtr
 		targetItab = s.expr(n.ITab)
@ -6241,15 +6259,16 @@ func (s *state) dynamicDottype(n *ir.DynamicTypeAssertExpr, commaok bool) (res,
 	} else {
 		target = s.expr(n.RType)
 	}
-	return s.dottype1(n.Pos(), n.X.Type(), n.Type(), iface, target, targetItab, commaok)
+	return s.dottype1(n.Pos(), n.X.Type(), n.Type(), iface, source, target, targetItab, commaok)
 }

 // dottype1 implements a x.(T) operation. iface is the argument (x), dst is the type we're asserting to (T)
 // and src is the type we're asserting from.
+// source is the *runtime._type of src
 // target is the *runtime._type of dst.
 // If src is a nonempty interface and dst is not an interface, targetItab is an itab representing (dst, src). Otherwise it is nil.
 // commaok is true if the caller wants a boolean success value. Otherwise, the generated code panics if the conversion fails.
-func (s *state) dottype1(pos src.XPos, src, dst *types.Type, iface, target, targetItab *ssa.Value, commaok bool) (res, resok *ssa.Value) {
+func (s *state) dottype1(pos src.XPos, src, dst *types.Type, iface, source, target, targetItab *ssa.Value, commaok bool) (res, resok *ssa.Value) {
 	byteptr := s.f.Config.Types.BytePtr
 	if dst.IsInterface() {
 		if dst.IsEmptyInterface() {
@ -6385,7 +6404,10 @@ func (s *state) dottype1(pos src.XPos, src, dst *types.Type, iface, target, targ
 	if !commaok {
 		// on failure, panic by calling panicdottype
 		s.startBlock(bFail)
-		taddr := s.reflectType(src)
+		taddr := source
+		if taddr == nil {
+			taddr = s.reflectType(src)
+		}
 		if src.IsEmptyInterface() {
 			s.rtcall(ir.Syms.PanicdottypeE, false, nil, itab, target, taddr)
 		} else {
--- a/src/cmd/compile/internal/typecheck/iexport.go
+++ b/src/cmd/compile/internal/typecheck/iexport.go
@ -405,7 +405,7 @@ func (w *exportWriter) writeIndex(index map[*types.Sym]uint64, mainIndex bool) {
 		w.string(exportPath(pkg))
 		if mainIndex {
 			w.string(pkg.Name)
-			w.uint64(uint64(pkg.Height))
+			w.uint64(0) // was package height, but not necessary anymore.
 		}

 		// Sort symbols within a package by name.
@ -1978,6 +1978,7 @@ func (w *exportWriter) expr(n ir.Node) {
 		w.pos(n.Pos())
 		w.typ(n.Type())
 		w.expr(n.X)
+		w.bool(n.Implicit())

 	case ir.OREAL, ir.OIMAG, ir.OCAP, ir.OCLOSE, ir.OLEN, ir.ONEW, ir.OPANIC:
 		n := n.(*ir.UnaryExpr)
--- a/src/cmd/compile/internal/typecheck/iimport.go
+++ b/src/cmd/compile/internal/typecheck/iimport.go
@ -175,10 +175,9 @@ func ReadImports(pkg *types.Pkg, data string) {
 	for nPkgs := ird.uint64(); nPkgs > 0; nPkgs-- {
 		pkg := p.pkgAt(ird.uint64())
 		pkgName := p.stringAt(ird.uint64())
-		pkgHeight := int(ird.uint64())
+		_ = int(ird.uint64()) // was package height, but not necessary anymore.
 		if pkg.Name == "" {
 			pkg.Name = pkgName
-			pkg.Height = pkgHeight
 			types.NumImport[pkgName]++

 			// TODO(mdempsky): This belongs somewhere else.
@ -187,9 +186,6 @@ func ReadImports(pkg *types.Pkg, data string) {
 			if pkg.Name != pkgName {
 				base.Fatalf("conflicting package names %v and %v for path %q", pkg.Name, pkgName, pkg.Path)
 			}
-			if pkg.Height != pkgHeight {
-				base.Fatalf("conflicting package heights %v and %v for path %q", pkg.Height, pkgHeight, pkg.Path)
-			}
 		}

 		for nSyms := ird.uint64(); nSyms > 0; nSyms-- {
@ -1493,7 +1489,9 @@ func (r *importReader) node() ir.Node {
 		return n

 	case ir.OCONV, ir.OCONVIFACE, ir.OCONVIDATA, ir.OCONVNOP, ir.OBYTES2STR, ir.ORUNES2STR, ir.OSTR2BYTES, ir.OSTR2RUNES, ir.ORUNESTR, ir.OSLICE2ARRPTR:
-		return ir.NewConvExpr(r.pos(), op, r.typ(), r.expr())
+		n := ir.NewConvExpr(r.pos(), op, r.typ(), r.expr())
+		n.SetImplicit(r.bool())
+		return n

 	case ir.OCOPY, ir.OCOMPLEX, ir.OREAL, ir.OIMAG, ir.OAPPEND, ir.OCAP, ir.OCLOSE, ir.ODELETE, ir.OLEN, ir.OMAKE, ir.ONEW, ir.OPANIC, ir.ORECOVER, ir.OPRINT, ir.OPRINTN, ir.OUNSAFEADD, ir.OUNSAFESLICE:
 		pos := r.pos()
--- a/src/cmd/compile/internal/typecheck/subr.go
+++ b/src/cmd/compile/internal/typecheck/subr.go
@ -13,6 +13,7 @@ import (
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
 	"cmd/compile/internal/types"
+	"cmd/internal/obj"
 	"cmd/internal/objabi"
 	"cmd/internal/src"
 )
@ -119,6 +120,13 @@ func ComputeAddrtaken(top []ir.Node) {
 	}
 }

+// LinksymAddr returns a new expression that evaluates to the address
+// of lsym. typ specifies the type of the addressed memory.
+func LinksymAddr(pos src.XPos, lsym *obj.LSym, typ *types.Type) *ir.AddrExpr {
+	n := ir.NewLinksymExpr(pos, lsym, typ)
+	return Expr(NodAddrAt(pos, n)).(*ir.AddrExpr)
+}
+
 func NodNil() ir.Node {
 	n := ir.NewNilExpr(base.Pos)
 	n.SetType(types.Types[types.TNIL])
@ -293,24 +301,14 @@ func assignconvfn(n ir.Node, t *types.Type, context func() string) ir.Node {

 	n = convlit1(n, t, false, context)
 	if n.Type() == nil {
-		return n
+		base.Fatalf("cannot assign %v to %v", n, t)
+	}
+	if n.Type().IsUntyped() {
+		base.Fatalf("%L has untyped type", n)
 	}
 	if t.Kind() == types.TBLANK {
 		return n
 	}
-
-	// Convert ideal bool from comparison to plain bool
-	// if the next step is non-bool (like interface{}).
-	if n.Type() == types.UntypedBool && !t.IsBoolean() {
-		if n.Op() == ir.ONAME || n.Op() == ir.OLITERAL {
-			r := ir.NewConvExpr(base.Pos, ir.OCONVNOP, nil, n)
-			r.SetType(types.Types[types.TBOOL])
-			r.SetTypecheck(1)
-			r.SetImplicit(true)
-			n = r
-		}
-	}
-
 	if types.Identical(n.Type(), t) {
 		return n
 	}
--- a/src/cmd/compile/internal/types/pkg.go
+++ b/src/cmd/compile/internal/types/pkg.go
@ -16,9 +16,6 @@ import (
 // pkgMap maps a package path to a package.
 var pkgMap = make(map[string]*Pkg)

-// MaxPkgHeight is a height greater than any likely package height.
-const MaxPkgHeight = 1e9
-
 type Pkg struct {
 	Path    string // string literal used in import statement, e.g. "runtime/internal/sys"
 	Name    string // package name, e.g. "sys"
@ -26,12 +23,6 @@ type Pkg struct {
 	Syms    map[string]*Sym
 	Pathsym *obj.LSym

-	// Height is the package's height in the import graph. Leaf
-	// packages (i.e., packages with no imports) have height 0,
-	// and all other packages have height 1 plus the maximum
-	// height of their imported packages.
-	Height int
-
 	Direct bool // imported directly
 }

--- a/src/cmd/compile/internal/types/sym.go
+++ b/src/cmd/compile/internal/types/sym.go
@ -97,14 +97,7 @@ func (sym *Sym) LinksymABI(abi obj.ABI) *obj.LSym {
 // Less reports whether symbol a is ordered before symbol b.
 //
 // Symbols are ordered exported before non-exported, then by name, and
-// finally (for non-exported symbols) by package height and path.
-//
-// Ordering by package height is necessary to establish a consistent
-// ordering for non-exported names with the same spelling but from
-// different packages. We don't necessarily know the path for the
-// package being compiled, but by definition it will have a height
-// greater than any other packages seen within the compilation unit.
-// For more background, see issue #24693.
+// finally (for non-exported symbols) by package path.
 func (a *Sym) Less(b *Sym) bool {
 	if a == b {
 		return false
@ -131,9 +124,6 @@ func (a *Sym) Less(b *Sym) bool {
 		return a.Name < b.Name
 	}
 	if !ea {
-		if a.Pkg.Height != b.Pkg.Height {
-			return a.Pkg.Height < b.Pkg.Height
-		}
 		return a.Pkg.Path < b.Pkg.Path
 	}
 	return false
--- a/src/cmd/compile/internal/types2/object.go
+++ b/src/cmd/compile/internal/types2/object.go
@ -189,7 +189,7 @@ func (obj *object) sameId(pkg *Package, name string) bool {
 //
 // Objects are ordered nil before non-nil, exported before
 // non-exported, then by name, and finally (for non-exported
-// functions) by package height and path.
+// functions) by package path.
 func (a *object) less(b *object) bool {
 	if a == b {
 		return false
@ -215,9 +215,6 @@ func (a *object) less(b *object) bool {
 		return a.name < b.name
 	}
 	if !ea {
-		if a.pkg.height != b.pkg.height {
-			return a.pkg.height < b.pkg.height
-		}
 		return a.pkg.path < b.pkg.path
 	}

--- a/src/cmd/compile/internal/types2/package.go
+++ b/src/cmd/compile/internal/types2/package.go
@ -14,7 +14,6 @@ type Package struct {
 	name     string
 	scope    *Scope
 	imports  []*Package
-	height   int
 	complete bool
 	fake     bool // scope lookup errors are silently dropped if package is fake (internal use only)
 	cgo      bool // uses of this package will be rewritten into uses of declarations from _cgo_gotypes.go
@ -23,14 +22,8 @@ type Package struct {
 // NewPackage returns a new Package for the given package path and name.
 // The package is not complete and contains no explicit imports.
 func NewPackage(path, name string) *Package {
-	return NewPackageHeight(path, name, 0)
-}
-
-// NewPackageHeight is like NewPackage, but allows specifying the
-// package's height.
-func NewPackageHeight(path, name string, height int) *Package {
 	scope := NewScope(Universe, nopos, nopos, fmt.Sprintf("package %q", path))
-	return &Package{path: path, name: name, scope: scope, height: height}
+	return &Package{path: path, name: name, scope: scope}
 }

 // Path returns the package path.
@ -39,9 +32,6 @@ func (pkg *Package) Path() string { return pkg.path }
 // Name returns the package name.
 func (pkg *Package) Name() string { return pkg.name }

-// Height returns the package height.
-func (pkg *Package) Height() int { return pkg.height }
-
 // SetName sets the package name.
 func (pkg *Package) SetName(name string) { pkg.name = name }

--- a/src/cmd/compile/internal/types2/resolver.go
+++ b/src/cmd/compile/internal/types2/resolver.go
@ -197,7 +197,6 @@ func (check *Checker) importPackage(pos syntax.Pos, path, dir string) *Package {
 // methods with receiver base type names.
 func (check *Checker) collectObjects() {
 	pkg := check.pkg
-	pkg.height = 0

 	// pkgImports is the set of packages already imported by any package file seen
 	// so far. Used to avoid duplicate entries in pkg.imports. Allocate and populate
@ -255,15 +254,6 @@ func (check *Checker) collectObjects() {
 					continue
 				}

-				if imp == Unsafe {
-					// typecheck ignores imports of package unsafe for
-					// calculating height.
-					// TODO(mdempsky): Revisit this. This seems fine, but I
-					// don't remember explicitly considering this case.
-				} else if h := imp.height + 1; h > pkg.height {
-					pkg.height = h
-				}
-
 				// local name overrides imported package name
 				name := imp.name
 				if s.LocalPkgName != nil {
--- a/src/cmd/compile/internal/types2/sizeof_test.go
+++ b/src/cmd/compile/internal/types2/sizeof_test.go
@ -47,7 +47,7 @@ func TestSizeof(t *testing.T) {

 		// Misc
 		{Scope{}, 60, 104},
-		{Package{}, 40, 80},
+		{Package{}, 36, 72},
 		{_TypeSet{}, 28, 56},
 	}

--- a/src/cmd/compile/internal/walk/assign.go
+++ b/src/cmd/compile/internal/walk/assign.go
@ -99,10 +99,11 @@ func walkAssign(init *ir.Nodes, n ir.Node) ir.Node {
 		}
 		as.Y = r
 		if r.Op() == ir.OAPPEND {
+			r := r.(*ir.CallExpr)
 			// Left in place for back end.
 			// Do not add a new write barrier.
 			// Set up address of type for back end.
-			r.(*ir.CallExpr).X = reflectdata.TypePtr(r.Type().Elem())
+			r.X = reflectdata.AppendElemRType(base.Pos, r)
 			return as
 		}
 		// Otherwise, lowered for race detector.
@ -169,11 +170,11 @@ func walkAssignMapRead(init *ir.Nodes, n *ir.AssignListStmt) ir.Node {
 	var call *ir.CallExpr
 	if w := t.Elem().Size(); w <= zeroValSize {
 		fn := mapfn(mapaccess2[fast], t, false)
-		call = mkcall1(fn, fn.Type().Results(), init, reflectdata.TypePtr(t), r.X, key)
+		call = mkcall1(fn, fn.Type().Results(), init, reflectdata.IndexMapRType(base.Pos, r), r.X, key)
 	} else {
 		fn := mapfn("mapaccess2_fat", t, true)
 		z := reflectdata.ZeroAddr(w)
-		call = mkcall1(fn, fn.Type().Results(), init, reflectdata.TypePtr(t), r.X, key, z)
+		call = mkcall1(fn, fn.Type().Results(), init, reflectdata.IndexMapRType(base.Pos, r), r.X, key, z)
 	}

 	// mapaccess2* returns a typed bool, but due to spec changes,
@ -502,7 +503,7 @@ func appendSlice(n *ir.CallExpr, init *ir.Nodes) ir.Node {
 	fn = typecheck.SubstArgTypes(fn, elemtype, elemtype)

 	// s = growslice(T, s, n)
-	nif.Body = []ir.Node{ir.NewAssignStmt(base.Pos, s, mkcall1(fn, s.Type(), nif.PtrInit(), reflectdata.TypePtr(elemtype), s, nn))}
+	nif.Body = []ir.Node{ir.NewAssignStmt(base.Pos, s, mkcall1(fn, s.Type(), nif.PtrInit(), reflectdata.AppendElemRType(base.Pos, n), s, nn))}
 	nodes.Append(nif)

 	// s = s[:n]
@ -523,7 +524,7 @@ func appendSlice(n *ir.CallExpr, init *ir.Nodes) ir.Node {
 		fn = typecheck.SubstArgTypes(fn, l1.Type().Elem(), l2.Type().Elem())
 		ptr1, len1 := backingArrayPtrLen(cheapExpr(slice, &nodes))
 		ptr2, len2 := backingArrayPtrLen(l2)
-		ncopy = mkcall1(fn, types.Types[types.TINT], &nodes, reflectdata.TypePtr(elemtype), ptr1, len1, ptr2, len2)
+		ncopy = mkcall1(fn, types.Types[types.TINT], &nodes, reflectdata.AppendElemRType(base.Pos, n), ptr1, len1, ptr2, len2)
 	} else if base.Flag.Cfg.Instrumenting && !base.Flag.CompilingRuntime {
 		// rely on runtime to instrument:
 		//  copy(s[len(l1):], l2)
@ -670,7 +671,7 @@ func extendSlice(n *ir.CallExpr, init *ir.Nodes) ir.Node {
 	fn = typecheck.SubstArgTypes(fn, elemtype, elemtype)

 	// s = growslice(T, s, n)
-	nif.Body = []ir.Node{ir.NewAssignStmt(base.Pos, s, mkcall1(fn, s.Type(), nif.PtrInit(), reflectdata.TypePtr(elemtype), s, nn))}
+	nif.Body = []ir.Node{ir.NewAssignStmt(base.Pos, s, mkcall1(fn, s.Type(), nif.PtrInit(), reflectdata.AppendElemRType(base.Pos, n), s, nn))}
 	nodes = append(nodes, nif)

 	// s = s[:n]
--- a/src/cmd/compile/internal/walk/builtin.go
+++ b/src/cmd/compile/internal/walk/builtin.go
@ -87,7 +87,7 @@ func walkAppend(n *ir.CallExpr, init *ir.Nodes, dst ir.Node) ir.Node {
 	fn := typecheck.LookupRuntime("growslice") //   growslice(<type>, old []T, mincap int) (ret []T)
 	fn = typecheck.SubstArgTypes(fn, ns.Type().Elem(), ns.Type().Elem())

-	nif.Body = []ir.Node{ir.NewAssignStmt(base.Pos, ns, mkcall1(fn, ns.Type(), nif.PtrInit(), reflectdata.TypePtr(ns.Type().Elem()), ns,
+	nif.Body = []ir.Node{ir.NewAssignStmt(base.Pos, ns, mkcall1(fn, ns.Type(), nif.PtrInit(), reflectdata.AppendElemRType(base.Pos, n), ns,
 		ir.NewBinaryExpr(base.Pos, ir.OADD, ir.NewUnaryExpr(base.Pos, ir.OLEN, ns), na)))}

 	l = append(l, nif)
@ -141,7 +141,7 @@ func walkCopy(n *ir.BinaryExpr, init *ir.Nodes, runtimecall bool) ir.Node {
 		ptrL, lenL := backingArrayPtrLen(n.X)
 		n.Y = cheapExpr(n.Y, init)
 		ptrR, lenR := backingArrayPtrLen(n.Y)
-		return mkcall1(fn, n.Type(), init, reflectdata.TypePtr(n.X.Type().Elem()), ptrL, lenL, ptrR, lenR)
+		return mkcall1(fn, n.Type(), init, reflectdata.CopyElemRType(base.Pos, n), ptrL, lenL, ptrR, lenR)
 	}

 	if runtimecall {
@ -214,7 +214,7 @@ func walkDelete(init *ir.Nodes, n *ir.CallExpr) ir.Node {
 	t := map_.Type()
 	fast := mapfast(t)
 	key = mapKeyArg(fast, n, key, false)
-	return mkcall1(mapfndel(mapdelete[fast], t), nil, init, reflectdata.TypePtr(t), map_, key)
+	return mkcall1(mapfndel(mapdelete[fast], t), nil, init, reflectdata.DeleteMapRType(base.Pos, n), map_, key)
 }

 // walkLenCap walks an OLEN or OCAP node.
@ -258,7 +258,7 @@ func walkMakeChan(n *ir.MakeExpr, init *ir.Nodes) ir.Node {
 		argtype = types.Types[types.TINT]
 	}

-	return mkcall1(chanfn(fnname, 1, n.Type()), n.Type(), init, reflectdata.TypePtr(n.Type()), typecheck.Conv(size, argtype))
+	return mkcall1(chanfn(fnname, 1, n.Type()), n.Type(), init, reflectdata.MakeChanRType(base.Pos, n), typecheck.Conv(size, argtype))
 }

 // walkMakeMap walks an OMAKEMAP node.
@ -356,7 +356,7 @@ func walkMakeMap(n *ir.MakeExpr, init *ir.Nodes) ir.Node {

 	fn := typecheck.LookupRuntime(fnname)
 	fn = typecheck.SubstArgTypes(fn, hmapType, t.Key(), t.Elem())
-	return mkcall1(fn, n.Type(), init, reflectdata.TypePtr(n.Type()), typecheck.Conv(hint, argtype), h)
+	return mkcall1(fn, n.Type(), init, reflectdata.MakeMapRType(base.Pos, n), typecheck.Conv(hint, argtype), h)
 }

 // walkMakeSlice walks an OMAKESLICE node.
@ -421,7 +421,7 @@ func walkMakeSlice(n *ir.MakeExpr, init *ir.Nodes) ir.Node {
 		argtype = types.Types[types.TINT]
 	}
 	fn := typecheck.LookupRuntime(fnname)
-	ptr := mkcall1(fn, types.Types[types.TUNSAFEPTR], init, reflectdata.TypePtr(t.Elem()), typecheck.Conv(len, argtype), typecheck.Conv(cap, argtype))
+	ptr := mkcall1(fn, types.Types[types.TUNSAFEPTR], init, reflectdata.MakeSliceElemRType(base.Pos, n), typecheck.Conv(len, argtype), typecheck.Conv(cap, argtype))
 	ptr.MarkNonNil()
 	len = typecheck.Conv(len, types.Types[types.TINT])
 	cap = typecheck.Conv(cap, types.Types[types.TINT])
@ -475,7 +475,7 @@ func walkMakeSliceCopy(n *ir.MakeExpr, init *ir.Nodes) ir.Node {
 	// Replace make+copy with runtime.makeslicecopy.
 	// instantiate makeslicecopy(typ *byte, tolen int, fromlen int, from unsafe.Pointer) unsafe.Pointer
 	fn := typecheck.LookupRuntime("makeslicecopy")
-	ptr := mkcall1(fn, types.Types[types.TUNSAFEPTR], init, reflectdata.TypePtr(t.Elem()), length, copylen, typecheck.Conv(copyptr, types.Types[types.TUNSAFEPTR]))
+	ptr := mkcall1(fn, types.Types[types.TUNSAFEPTR], init, reflectdata.MakeSliceElemRType(base.Pos, n), length, copylen, typecheck.Conv(copyptr, types.Types[types.TUNSAFEPTR]))
 	ptr.MarkNonNil()
 	sh := ir.NewSliceHeaderExpr(base.Pos, t, ptr, length, length)
 	return walkExpr(typecheck.Expr(sh), init)
@ -658,7 +658,7 @@ func walkUnsafeSlice(n *ir.BinaryExpr, init *ir.Nodes) ir.Node {
 	if ir.ShouldCheckPtr(ir.CurFunc, 1) {
 		fnname := "unsafeslicecheckptr"
 		fn := typecheck.LookupRuntime(fnname)
-		init.Append(mkcall1(fn, nil, init, reflectdata.TypePtr(sliceType.Elem()), unsafePtr, typecheck.Conv(len, lenType)))
+		init.Append(mkcall1(fn, nil, init, reflectdata.UnsafeSliceElemRType(base.Pos, n), unsafePtr, typecheck.Conv(len, lenType)))
 	} else {
 		// Otherwise, open code unsafe.Slice to prevent runtime call overhead.
 		// Keep this code in sync with runtime.unsafeslice{,64}
--- a/src/cmd/compile/internal/walk/compare.go
+++ b/src/cmd/compile/internal/walk/compare.go
@ -54,6 +54,10 @@ func walkCompare(n *ir.BinaryExpr, init *ir.Nodes) ir.Node {
 	// Given mixed interface/concrete comparison,
 	// rewrite into types-equal && data-equal.
 	// This is efficient, avoids allocations, and avoids runtime calls.
+	//
+	// TODO(mdempsky): It would be more general and probably overall
+	// simpler to just extend walkCompareInterface to optimize when one
+	// operand is an OCONVIFACE.
 	if n.X.Type().IsInterface() != n.Y.Type().IsInterface() {
 		// Preserve side-effects in case of short-circuiting; see #32187.
 		l := cheapExpr(n.X, init)
@ -74,9 +78,12 @@ func walkCompare(n *ir.BinaryExpr, init *ir.Nodes) ir.Node {
 		//   l.tab == type(r)
 		// For non-empty interface, this is:
 		//   l.tab != nil && l.tab._type == type(r)
+		//
+		// TODO(mdempsky): For non-empty interface comparisons, just
+		// compare against the itab address directly?
 		var eqtype ir.Node
 		tab := ir.NewUnaryExpr(base.Pos, ir.OITAB, l)
-		rtyp := reflectdata.TypePtr(r.Type())
+		rtyp := reflectdata.CompareRType(base.Pos, n)
 		if l.Type().IsEmptyInterface() {
 			tab.SetType(types.NewPtr(types.Types[types.TUINT8]))
 			tab.SetTypecheck(1)
--- a/src/cmd/compile/internal/walk/complit.go
+++ b/src/cmd/compile/internal/walk/complit.go
@ -414,9 +414,10 @@ func slicelit(ctxt initContext, n *ir.CompLitExpr, var_ ir.Node, init *ir.Nodes)

 func maplit(n *ir.CompLitExpr, m ir.Node, init *ir.Nodes) {
 	// make the map var
-	a := ir.NewCallExpr(base.Pos, ir.OMAKE, nil, nil)
+	args := []ir.Node{ir.TypeNode(n.Type()), ir.NewInt(n.Len + int64(len(n.List)))}
+	a := typecheck.Expr(ir.NewCallExpr(base.Pos, ir.OMAKE, nil, args)).(*ir.MakeExpr)
+	a.RType = n.RType
 	a.SetEsc(n.Esc())
-	a.Args = []ir.Node{ir.TypeNode(n.Type()), ir.NewInt(n.Len + int64(len(n.List)))}
 	appendWalkStmt(init, ir.NewAssignStmt(base.Pos, m, a))

 	entries := n.List
@ -467,14 +468,18 @@ func maplit(n *ir.CompLitExpr, m ir.Node, init *ir.Nodes) {

 		kidx := ir.NewIndexExpr(base.Pos, vstatk, i)
 		kidx.SetBounded(true)
-		lhs := ir.NewIndexExpr(base.Pos, m, kidx)
+
+		// typechecker rewrites OINDEX to OINDEXMAP
+		lhs := typecheck.AssignExpr(ir.NewIndexExpr(base.Pos, m, kidx)).(*ir.IndexExpr)
+		base.AssertfAt(lhs.Op() == ir.OINDEXMAP, lhs.Pos(), "want OINDEXMAP, have %+v", lhs)
+		lhs.RType = n.RType

 		zero := ir.NewAssignStmt(base.Pos, i, ir.NewInt(0))
 		cond := ir.NewBinaryExpr(base.Pos, ir.OLT, i, ir.NewInt(tk.NumElem()))
 		incr := ir.NewAssignStmt(base.Pos, i, ir.NewBinaryExpr(base.Pos, ir.OADD, i, ir.NewInt(1)))

 		var body ir.Node = ir.NewAssignStmt(base.Pos, lhs, rhs)
-		body = typecheck.Stmt(body) // typechecker rewrites OINDEX to OINDEXMAP
+		body = typecheck.Stmt(body)
 		body = orderStmtInPlace(body, map[string][]*ir.Name{})

 		loop := ir.NewForStmt(base.Pos, nil, cond, incr, nil)
@ -503,8 +508,14 @@ func maplit(n *ir.CompLitExpr, m ir.Node, init *ir.Nodes) {
 		appendWalkStmt(init, ir.NewAssignStmt(base.Pos, tmpelem, elem))

 		ir.SetPos(tmpelem)
-		var a ir.Node = ir.NewAssignStmt(base.Pos, ir.NewIndexExpr(base.Pos, m, tmpkey), tmpelem)
-		a = typecheck.Stmt(a) // typechecker rewrites OINDEX to OINDEXMAP
+
+		// typechecker rewrites OINDEX to OINDEXMAP
+		lhs := typecheck.AssignExpr(ir.NewIndexExpr(base.Pos, m, tmpkey)).(*ir.IndexExpr)
+		base.AssertfAt(lhs.Op() == ir.OINDEXMAP, lhs.Pos(), "want OINDEXMAP, have %+v", lhs)
+		lhs.RType = n.RType
+
+		var a ir.Node = ir.NewAssignStmt(base.Pos, lhs, tmpelem)
+		a = typecheck.Stmt(a)
 		a = orderStmtInPlace(a, map[string][]*ir.Name{})
 		appendWalkStmt(init, a)
 	}
--- a/src/cmd/compile/internal/walk/convert.go
+++ b/src/cmd/compile/internal/walk/convert.go
@ -14,7 +14,6 @@ import (
 	"cmd/compile/internal/ssagen"
 	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
-	"cmd/internal/src"
 	"cmd/internal/sys"
 )

@ -50,13 +49,8 @@ func walkConvInterface(n *ir.ConvExpr, init *ir.Nodes) ir.Node {
 	}

 	if !fromType.IsInterface() {
-		var typeWord ir.Node
-		if toType.IsEmptyInterface() {
-			typeWord = reflectdata.TypePtr(fromType)
-		} else {
-			typeWord = reflectdata.ITabAddr(fromType, toType)
-		}
-		l := ir.NewBinaryExpr(base.Pos, ir.OEFACE, typeWord, dataWord(n.Pos(), n.X, init, n.Esc() != ir.EscNone))
+		typeWord := reflectdata.ConvIfaceTypeWord(base.Pos, n)
+		l := ir.NewBinaryExpr(base.Pos, ir.OEFACE, typeWord, dataWord(n, init))
 		l.SetType(toType)
 		l.SetTypecheck(n.Typecheck())
 		return l
@ -95,7 +89,7 @@ func walkConvInterface(n *ir.ConvExpr, init *ir.Nodes) ir.Node {
 		fn := typecheck.LookupRuntime("convI2I")
 		types.CalcSize(fn.Type())
 		call := ir.NewCallExpr(base.Pos, ir.OCALL, fn, nil)
-		call.Args = []ir.Node{reflectdata.TypePtr(toType), itab}
+		call.Args = []ir.Node{reflectdata.ConvIfaceTypeWord(base.Pos, n), itab}
 		typeWord = walkExpr(typecheck.Expr(call), init)
 	}

@ -107,10 +101,10 @@ func walkConvInterface(n *ir.ConvExpr, init *ir.Nodes) ir.Node {
 	return e
 }

-// Returns the data word (the second word) used to represent n in an interface.
-// n must not be of interface type.
-// esc describes whether the result escapes.
-func dataWord(pos src.XPos, n ir.Node, init *ir.Nodes, escapes bool) ir.Node {
+// Returns the data word (the second word) used to represent conv.X in
+// an interface.
+func dataWord(conv *ir.ConvExpr, init *ir.Nodes) ir.Node {
+	pos, n := conv.Pos(), conv.X
 	fromType := n.Type()

 	// If it's a pointer, it is its own representation.
@ -150,7 +144,7 @@ func dataWord(pos src.XPos, n ir.Node, init *ir.Nodes, escapes bool) ir.Node {
 	case n.Op() == ir.ONAME && n.(*ir.Name).Class == ir.PEXTERN && n.(*ir.Name).Readonly():
 		// n is a readonly global; use it directly.
 		value = n
-	case !escapes && fromType.Size() <= 1024:
+	case conv.Esc() == ir.EscNone && fromType.Size() <= 1024:
 		// n does not escape. Use a stack temporary initialized to n.
 		value = typecheck.Temp(fromType)
 		init.Append(typecheck.Stmt(ir.NewAssignStmt(base.Pos, value, n)))
@ -176,7 +170,7 @@ func dataWord(pos src.XPos, n ir.Node, init *ir.Nodes, escapes bool) ir.Node {
 			n = copyExpr(n, fromType, init)
 		}
 		fn = typecheck.SubstArgTypes(fn, fromType)
-		args = []ir.Node{reflectdata.TypePtr(fromType), typecheck.NodAddr(n)}
+		args = []ir.Node{reflectdata.ConvIfaceSrcRType(base.Pos, conv), typecheck.NodAddr(n)}
 	} else {
 		// Use a specialized conversion routine that takes the type being
 		// converted by value, not by pointer.
@ -211,7 +205,7 @@ func dataWord(pos src.XPos, n ir.Node, init *ir.Nodes, escapes bool) ir.Node {
 // walkConvIData walks an OCONVIDATA node.
 func walkConvIData(n *ir.ConvExpr, init *ir.Nodes) ir.Node {
 	n.X = walkExpr(n.X, init)
-	return dataWord(n.Pos(), n.X, init, n.Esc() != ir.EscNone)
+	return dataWord(n, init)
 }

 // walkBytesRunesToString walks an OBYTES2STR or ORUNES2STR node.
--- a/src/cmd/compile/internal/walk/expr.go
+++ b/src/cmd/compile/internal/walk/expr.go
@ -782,7 +782,7 @@ func walkIndexMap(n *ir.IndexExpr, init *ir.Nodes) ir.Node {
 	t := map_.Type()
 	fast := mapfast(t)
 	key := mapKeyArg(fast, n, n.Index, n.Assigned)
-	args := []ir.Node{reflectdata.TypePtr(t), map_, key}
+	args := []ir.Node{reflectdata.IndexMapRType(base.Pos, n), map_, key}

 	var mapFn ir.Node
 	switch {
--- a/src/cmd/compile/internal/walk/order.go
+++ b/src/cmd/compile/internal/walk/order.go
@ -993,7 +993,7 @@ func (o *orderState) stmt(n ir.Node) {
 				do(0, recv.X.Type().Elem())
 				do(1, types.Types[types.TBOOL])
 				if len(init) != 0 {
-					ir.DumpList("ninit", r.Init())
+					ir.DumpList("ninit", init)
 					base.Fatalf("ninit on select recv")
 				}
 				orderBlock(ncas.PtrInit(), o.free)
@ -1456,8 +1456,12 @@ func (o *orderState) expr1(n, lhs ir.Node) ir.Node {

 		// Emit eval+insert of dynamic entries, one at a time.
 		for _, r := range dynamics {
-			as := ir.NewAssignStmt(base.Pos, ir.NewIndexExpr(base.Pos, m, r.Key), r.Value)
-			typecheck.Stmt(as) // Note: this converts the OINDEX to an OINDEXMAP
+			lhs := typecheck.AssignExpr(ir.NewIndexExpr(base.Pos, m, r.Key)).(*ir.IndexExpr)
+			base.AssertfAt(lhs.Op() == ir.OINDEXMAP, lhs.Pos(), "want OINDEXMAP, have %+v", lhs)
+			lhs.RType = n.RType
+
+			as := ir.NewAssignStmt(base.Pos, lhs, r.Value)
+			typecheck.Stmt(as)
 			o.stmt(as)
 		}

--- a/src/cmd/compile/internal/walk/range.go
+++ b/src/cmd/compile/internal/walk/range.go
@ -38,11 +38,7 @@ func cheapComputableIndex(width int64) bool {
 // the returned node.
 func walkRange(nrange *ir.RangeStmt) ir.Node {
 	if isMapClear(nrange) {
-		m := nrange.X
-		lno := ir.SetPos(m)
-		n := mapClear(m)
-		base.Pos = lno
-		return n
+		return mapClear(nrange)
 	}

 	nfor := ir.NewForStmt(nrange.Pos(), nil, nil, nil, nil)
@ -107,7 +103,7 @@ func walkRange(nrange *ir.RangeStmt) ir.Node {

 		// for v1 := range ha { body }
 		if v2 == nil {
-			body = []ir.Node{ir.NewAssignStmt(base.Pos, v1, hv1)}
+			body = []ir.Node{rangeAssign(nrange, hv1)}
 			break
 		}

@ -116,10 +112,7 @@ func walkRange(nrange *ir.RangeStmt) ir.Node {
 			// v1, v2 = hv1, ha[hv1]
 			tmp := ir.NewIndexExpr(base.Pos, ha, hv1)
 			tmp.SetBounded(true)
-			// Use OAS2 to correctly handle assignments
-			// of the form "v1, a[v1] := range".
-			a := ir.NewAssignListStmt(base.Pos, ir.OAS2, []ir.Node{v1, v2}, []ir.Node{hv1, tmp})
-			body = []ir.Node{a}
+			body = []ir.Node{rangeAssign2(nrange, hv1, tmp)}
 			break
 		}

@ -144,9 +137,7 @@ func walkRange(nrange *ir.RangeStmt) ir.Node {
 		tmp.SetBounded(true)
 		init = append(init, ir.NewAssignStmt(base.Pos, hp, typecheck.NodAddr(tmp)))

-		// Use OAS2 to correctly handle assignments
-		// of the form "v1, a[v1] := range".
-		a := ir.NewAssignListStmt(base.Pos, ir.OAS2, []ir.Node{v1, v2}, []ir.Node{hv1, ir.NewStarExpr(base.Pos, hp)})
+		a := rangeAssign2(nrange, hv1, ir.NewStarExpr(base.Pos, hp))
 		body = append(body, a)

 		// Advance pointer as part of the late increment.
@ -172,7 +163,7 @@ func walkRange(nrange *ir.RangeStmt) ir.Node {
 		fn := typecheck.LookupRuntime("mapiterinit")

 		fn = typecheck.SubstArgTypes(fn, t.Key(), t.Elem(), th)
-		init = append(init, mkcallstmt1(fn, reflectdata.TypePtr(t), ha, typecheck.NodAddr(hit)))
+		init = append(init, mkcallstmt1(fn, reflectdata.RangeMapRType(base.Pos, nrange), ha, typecheck.NodAddr(hit)))
 		nfor.Cond = ir.NewBinaryExpr(base.Pos, ir.ONE, ir.NewSelectorExpr(base.Pos, ir.ODOT, hit, keysym), typecheck.NodNil())

 		fn = typecheck.LookupRuntime("mapiternext")
@ -183,11 +174,10 @@ func walkRange(nrange *ir.RangeStmt) ir.Node {
 		if v1 == nil {
 			body = nil
 		} else if v2 == nil {
-			body = []ir.Node{ir.NewAssignStmt(base.Pos, v1, key)}
+			body = []ir.Node{rangeAssign(nrange, key)}
 		} else {
 			elem := ir.NewStarExpr(base.Pos, ir.NewSelectorExpr(base.Pos, ir.ODOT, hit, elemsym))
-			a := ir.NewAssignListStmt(base.Pos, ir.OAS2, []ir.Node{v1, v2}, []ir.Node{key, elem})
-			body = []ir.Node{a}
+			body = []ir.Node{rangeAssign2(nrange, key, elem)}
 		}

 	case types.TCHAN:
@ -210,7 +200,7 @@ func walkRange(nrange *ir.RangeStmt) ir.Node {
 		if v1 == nil {
 			body = nil
 		} else {
-			body = []ir.Node{ir.NewAssignStmt(base.Pos, v1, hv1)}
+			body = []ir.Node{rangeAssign(nrange, hv1)}
 		}
 		// Zero hv1. This prevents hv1 from being the sole, inaccessible
 		// reference to an otherwise GC-able value during the next channel receive.
@ -275,11 +265,10 @@ func walkRange(nrange *ir.RangeStmt) ir.Node {
 		if v1 != nil {
 			if v2 != nil {
 				// v1, v2 = hv1t, hv2
-				a := ir.NewAssignListStmt(base.Pos, ir.OAS2, []ir.Node{v1, v2}, []ir.Node{hv1t, hv2})
-				body = append(body, a)
+				body = append(body, rangeAssign2(nrange, hv1t, hv2))
 			} else {
 				// v1 = hv1t
-				body = append(body, ir.NewAssignStmt(base.Pos, v1, hv1t))
+				body = append(body, rangeAssign(nrange, hv1t))
 			}
 		}
 	}
@ -314,6 +303,36 @@ func walkRange(nrange *ir.RangeStmt) ir.Node {
 	return n
 }

+// rangeAssign returns "n.Key = key".
+func rangeAssign(n *ir.RangeStmt, key ir.Node) ir.Node {
+	key = rangeConvert(n, n.Key.Type(), key, n.KeyTypeWord, n.KeySrcRType)
+	return ir.NewAssignStmt(n.Pos(), n.Key, key)
+}
+
+// rangeAssign2 returns "n.Key, n.Value = key, value".
+func rangeAssign2(n *ir.RangeStmt, key, value ir.Node) ir.Node {
+	// Use OAS2 to correctly handle assignments
+	// of the form "v1, a[v1] = range".
+	key = rangeConvert(n, n.Key.Type(), key, n.KeyTypeWord, n.KeySrcRType)
+	value = rangeConvert(n, n.Value.Type(), value, n.ValueTypeWord, n.ValueSrcRType)
+	return ir.NewAssignListStmt(n.Pos(), ir.OAS2, []ir.Node{n.Key, n.Value}, []ir.Node{key, value})
+}
+
+// rangeConvert returns src, converted to dst if necessary. If a
+// conversion is necessary, then typeWord and srcRType are copied to
+// their respective ConvExpr fields.
+func rangeConvert(nrange *ir.RangeStmt, dst *types.Type, src, typeWord, srcRType ir.Node) ir.Node {
+	src = typecheck.Expr(src)
+	if dst.Kind() == types.TBLANK || types.Identical(dst, src.Type()) {
+		return src
+	}
+
+	n := ir.NewConvExpr(nrange.Pos(), ir.OCONV, dst, src)
+	n.TypeWord = typeWord
+	n.SrcRType = srcRType
+	return typecheck.Expr(n)
+}
+
 // isMapClear checks if n is of the form:
 //
 //	for k := range m {
@ -360,13 +379,17 @@ func isMapClear(n *ir.RangeStmt) bool {
 }

 // mapClear constructs a call to runtime.mapclear for the map m.
-func mapClear(m ir.Node) ir.Node {
+func mapClear(nrange *ir.RangeStmt) ir.Node {
+	m := nrange.X
+	origPos := ir.SetPos(m)
+	defer func() { base.Pos = origPos }()
+
 	t := m.Type()

 	// instantiate mapclear(typ *type, hmap map[any]any)
 	fn := typecheck.LookupRuntime("mapclear")
 	fn = typecheck.SubstArgTypes(fn, t.Key(), t.Elem())
-	n := mkcallstmt1(fn, reflectdata.TypePtr(t), m)
+	n := mkcallstmt1(fn, reflectdata.RangeMapRType(base.Pos, nrange), m)
 	return walkStmt(typecheck.Stmt(n))
 }

--- a/src/cmd/compile/internal/walk/switch.go
+++ b/src/cmd/compile/internal/walk/switch.go
@ -85,8 +85,12 @@ func walkSwitchExpr(sw *ir.SwitchStmt) {
 			defaultGoto = jmp
 		}

-		for _, n1 := range ncase.List {
-			s.Add(ncase.Pos(), n1, jmp)
+		for i, n1 := range ncase.List {
+			var rtype ir.Node
+			if i < len(ncase.RTypes) {
+				rtype = ncase.RTypes[i]
+			}
+			s.Add(ncase.Pos(), n1, rtype, jmp)
 		}

 		// Process body.
@ -124,11 +128,12 @@ type exprSwitch struct {
 type exprClause struct {
 	pos    src.XPos
 	lo, hi ir.Node
+	rtype  ir.Node // *runtime._type for OEQ node
 	jmp    ir.Node
 }

-func (s *exprSwitch) Add(pos src.XPos, expr, jmp ir.Node) {
-	c := exprClause{pos: pos, lo: expr, hi: expr, jmp: jmp}
+func (s *exprSwitch) Add(pos src.XPos, expr, rtype, jmp ir.Node) {
+	c := exprClause{pos: pos, lo: expr, hi: expr, rtype: rtype, jmp: jmp}
 	if types.IsOrdered[s.exprname.Type().Kind()] && expr.Op() == ir.OLITERAL {
 		s.clauses = append(s.clauses, c)
 		return
@ -233,7 +238,7 @@ func (s *exprSwitch) flush() {
 			// Add length case to outer switch.
 			cas := ir.NewBasicLit(pos, constant.MakeInt64(runLen(run)))
 			jmp := ir.NewBranchStmt(pos, ir.OGOTO, label)
-			outer.Add(pos, cas, jmp)
+			outer.Add(pos, cas, nil, jmp)
 		}
 		s.done.Append(ir.NewLabelStmt(s.pos, outerLabel))
 		outer.Emit(&s.done)
@ -342,7 +347,9 @@ func (c *exprClause) test(exprname ir.Node) ir.Node {
 		}
 	}

-	return ir.NewBinaryExpr(c.pos, ir.OEQ, exprname, c.lo)
+	n := ir.NewBinaryExpr(c.pos, ir.OEQ, exprname, c.lo)
+	n.RType = c.rtype
+	return n
 }

 func allCaseExprsAreSideEffectFree(sw *ir.SwitchStmt) bool {
--- a/src/go/internal/gcimporter/gcimporter_test.go
+++ b/src/go/internal/gcimporter/gcimporter_test.go
@ -583,6 +583,30 @@ func TestIssue13566(t *testing.T) {
 	}
 }

+func TestTypeNamingOrder(t *testing.T) {
+	skipSpecialPlatforms(t)
+
+	// This package only handles gc export data.
+	if runtime.Compiler != "gc" {
+		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
+	}
+
+	// On windows, we have to set the -D option for the compiler to avoid having a drive
+	// letter and an illegal ':' in the import path - just skip it (see also issue #3483).
+	if runtime.GOOS == "windows" {
+		t.Skip("avoid dealing with relative paths/drive letters on windows")
+	}
+
+	tmpdir := mktmpdir(t)
+	defer os.RemoveAll(tmpdir)
+	testoutdir := filepath.Join(tmpdir, "testdata")
+
+	compile(t, "testdata", "g.go", testoutdir)
+
+	// import must succeed (test for issue at hand)
+	_ = importPkg(t, "./testdata/g", tmpdir)
+}
+
 func TestIssue13898(t *testing.T) {
 	skipSpecialPlatforms(t)

--- a/src/go/internal/gcimporter/testdata/g.go
+++ b/src/go/internal/gcimporter/testdata/g.go
@ -0,0 +1,23 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Input for TestTypeNamingOrder
+
+// ensures that the order in which "type A B" declarations are
+// processed is correct; this was a problem for unified IR imports.
+
+package g
+
+type Client struct {
+	common service
+	A      *AService
+	B      *BService
+}
+
+type service struct {
+	client *Client
+}
+
+type AService service
+type BService service
--- a/src/go/internal/gcimporter/ureader.go
+++ b/src/go/internal/gcimporter/ureader.go
@ -31,6 +31,8 @@ type pkgReader struct {
 	// laterFns holds functions that need to be invoked at the end of
 	// import reading.
 	laterFns []func()
+	// laterFors is used in case of 'type A B' to ensure that B is processed before A.
+	laterFors map[types.Type]int
 }

 // later adds a function to be invoked at the end of import reading.
@ -38,6 +40,15 @@ func (pr *pkgReader) later(fn func()) {
 	pr.laterFns = append(pr.laterFns, fn)
 }

+// laterFor adds a function to be invoked at the end of import reading, and records the type that function is finishing.
+func (pr *pkgReader) laterFor(t types.Type, fn func()) {
+	if pr.laterFors == nil {
+		pr.laterFors = make(map[types.Type]int)
+	}
+	pr.laterFors[t] = len(pr.laterFns)
+	pr.laterFns = append(pr.laterFns, fn)
+}
+
 // readUnifiedPackage reads a package description from the given
 // unified IR export data decoder.
 func readUnifiedPackage(fset *token.FileSet, ctxt *types.Context, imports map[string]*types.Package, input pkgbits.PkgDecoder) *types.Package {
@ -60,7 +71,7 @@ func readUnifiedPackage(fset *token.FileSet, ctxt *types.Context, imports map[st

 	r := pr.newReader(pkgbits.RelocMeta, pkgbits.PublicRootIdx, pkgbits.SyncPublic)
 	pkg := r.pkg()
-	r.Bool() // has init
+	r.Bool() // TODO(mdempsky): Remove; was "has init"

 	for i, n := 0, r.Len(); i < n; i++ {
 		// As if r.obj(), but avoiding the Scope.Lookup call,
@ -198,21 +209,49 @@ func (r *reader) doPkg() *types.Package {
 	}

 	name := r.String()
-	height := r.Len()

-	// Was: "pkg := types.NewPackageHeight(path, name, height)"
-	pkg, _ := types.NewPackage(path, name), height
+	pkg := types.NewPackage(path, name)
 	r.p.imports[path] = pkg

 	imports := make([]*types.Package, r.Len())
 	for i := range imports {
 		imports[i] = r.pkg()
 	}
-	pkg.SetImports(imports)
+
+	// The documentation for (*types.Package).Imports requires
+	// flattening the import graph when reading from export data, as
+	// obviously incorrect as that is.
+	//
+	// TODO(mdempsky): Remove this if go.dev/issue/54096 is accepted.
+	pkg.SetImports(flattenImports(imports))

 	return pkg
 }

+// flattenImports returns the transitive closure of all imported
+// packages rooted from pkgs.
+func flattenImports(pkgs []*types.Package) []*types.Package {
+	var res []*types.Package
+
+	seen := make(map[*types.Package]bool)
+	var add func(pkg *types.Package)
+	add = func(pkg *types.Package) {
+		if seen[pkg] {
+			return
+		}
+		seen[pkg] = true
+		res = append(res, pkg)
+		for _, imp := range pkg.Imports() {
+			add(imp)
+		}
+	}
+
+	for _, pkg := range pkgs {
+		add(pkg)
+	}
+	return res
+}
+
 // @@@ Types

 func (r *reader) typ() types.Type {
@ -459,7 +498,15 @@ func (pr *pkgReader) objIdx(idx pkgbits.Index) (*types.Package, string) {
 			// unit tests expected that), but cmd/compile doesn't care
 			// about it, so maybe we can avoid worrying about that here.
 			rhs := r.typ()
-			r.p.later(func() {
+			pk := r.p
+			pk.laterFor(named, func() {
+				// First be sure that the rhs is initialized, if it needs to be initialized.
+				delete(pk.laterFors, named) // prevent cycles
+				if i, ok := pk.laterFors[rhs]; ok {
+					f := pk.laterFns[i]
+					pk.laterFns[i] = func() {} // function is running now, so replace it with a no-op
+					f()                        // initialize RHS
+				}
 				underlying := rhs.Underlying()
 				named.SetUnderlying(underlying)
 			})
--- a/src/internal/pkgbits/decoder.go
+++ b/src/internal/pkgbits/decoder.go
@ -18,6 +18,12 @@ import (
 // A PkgDecoder provides methods for decoding a package's Unified IR
 // export data.
 type PkgDecoder struct {
+	// version is the file format version.
+	version uint32
+
+	// sync indicates whether the file uses sync markers.
+	sync bool
+
 	// pkgPath is the package path for the package to be decoded.
 	//
 	// TODO(mdempsky): Remove; unneeded since CL 391014.
@ -52,6 +58,9 @@ type PkgDecoder struct {
 // TODO(mdempsky): Remove; unneeded since CL 391014.
 func (pr *PkgDecoder) PkgPath() string { return pr.pkgPath }

+// SyncMarkers reports whether pr uses sync markers.
+func (pr *PkgDecoder) SyncMarkers() bool { return pr.sync }
+
 // NewPkgDecoder returns a PkgDecoder initialized to read the Unified
 // IR export data from input. pkgPath is the package path for the
 // compilation unit that produced the export data.
@ -67,9 +76,18 @@ func NewPkgDecoder(pkgPath, input string) PkgDecoder {

 	r := strings.NewReader(input)

-	var version uint32
-	assert(binary.Read(r, binary.LittleEndian, &version) == nil)
-	assert(version == 0)
+	assert(binary.Read(r, binary.LittleEndian, &pr.version) == nil)
+
+	switch pr.version {
+	default:
+		panic(fmt.Errorf("unsupported version: %v", pr.version))
+	case 0:
+		// no flags
+	case 1:
+		var flags uint32
+		assert(binary.Read(r, binary.LittleEndian, &flags) == nil)
+		pr.sync = flags&flagSyncMarkers != 0
+	}

 	assert(binary.Read(r, binary.LittleEndian, pr.elemEndsEnds[:]) == nil)

@ -215,7 +233,7 @@ func (r *Decoder) rawReloc(k RelocKind, idx int) Index {
 //
 // If EnableSync is false, then Sync is a no-op.
 func (r *Decoder) Sync(mWant SyncMarker) {
-	if !EnableSync {
+	if !r.common.sync {
 		return
 	}

--- a/src/internal/pkgbits/encoder.go
+++ b/src/internal/pkgbits/encoder.go
@ -14,6 +14,16 @@ import (
 	"runtime"
 )

+// currentVersion is the current version number.
+//
+//   - v0: initial prototype
+//
+//   - v1: adds the flags uint32 word
+//
+// TODO(mdempsky): For the next version bump:
+//   - remove the legacy "has init" bool from the public root
+const currentVersion uint32 = 1
+
 // A PkgEncoder provides methods for encoding a package's Unified IR
 // export data.
 type PkgEncoder struct {
@ -25,15 +35,21 @@ type PkgEncoder struct {
 	// elems[RelocString][stringsIdx[s]] == s (if present).
 	stringsIdx map[string]Index

+	// syncFrames is the number of frames to write at each sync
+	// marker. A negative value means sync markers are omitted.
 	syncFrames int
 }

+// SyncMarkers reports whether pw uses sync markers.
+func (pw *PkgEncoder) SyncMarkers() bool { return pw.syncFrames >= 0 }
+
 // NewPkgEncoder returns an initialized PkgEncoder.
 //
 // syncFrames is the number of caller frames that should be serialized
 // at Sync points. Serializing additional frames results in larger
 // export data files, but can help diagnosing desync errors in
-// higher-level Unified IR reader/writer code.
+// higher-level Unified IR reader/writer code. If syncFrames is
+// negative, then sync markers are omitted entirely.
 func NewPkgEncoder(syncFrames int) PkgEncoder {
 	return PkgEncoder{
 		stringsIdx: make(map[string]Index),
@ -51,7 +67,13 @@ func (pw *PkgEncoder) DumpTo(out0 io.Writer) (fingerprint [8]byte) {
 		assert(binary.Write(out, binary.LittleEndian, x) == nil)
 	}

-	writeUint32(0) // version
+	writeUint32(currentVersion)
+
+	var flags uint32
+	if pw.SyncMarkers() {
+		flags |= flagSyncMarkers
+	}
+	writeUint32(flags)

 	// Write elemEndsEnds.
 	var sum uint32
@ -204,7 +226,7 @@ func (w *Encoder) rawReloc(r RelocKind, idx Index) int {
 }

 func (w *Encoder) Sync(m SyncMarker) {
-	if !EnableSync {
+	if !w.p.SyncMarkers() {
 		return
 	}

@ -297,8 +319,14 @@ func (w *Encoder) Code(c Code) {
 // section (if not already present), and then writing a relocation
 // into the element bitstream.
 func (w *Encoder) String(s string) {
+	w.StringRef(w.p.StringIdx(s))
+}
+
+// StringRef writes a reference to the given index, which must be a
+// previously encoded string value.
+func (w *Encoder) StringRef(idx Index) {
 	w.Sync(SyncString)
-	w.Reloc(RelocString, w.p.StringIdx(s))
+	w.Reloc(RelocString, idx)
 }

 // Strings encodes and writes a variable-length slice of strings into
--- a/src/internal/pkgbits/flags.go
+++ b/src/internal/pkgbits/flags.go
@ -0,0 +1,9 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package pkgbits
+
+const (
+	flagSyncMarkers = 1 << iota // file format contains sync markers
+)
--- a/src/internal/pkgbits/sync.go
+++ b/src/internal/pkgbits/sync.go
@ -10,17 +10,6 @@ import (
 	"strings"
 )

-// EnableSync controls whether sync markers are written into unified
-// IR's export data format and also whether they're expected when
-// reading them back in. They're inessential to the correct
-// functioning of unified IR, but are helpful during development to
-// detect mistakes.
-//
-// When sync is enabled, writer stack frames will also be included in
-// the export data. Currently, a fixed number of frames are included,
-// controlled by -d=syncframes (default 0).
-const EnableSync = true
-
 // fmtFrames formats a backtrace for reporting reader/writer desyncs.
 func fmtFrames(pcs ...uintptr) []string {
 	res := make([]string, 0, len(pcs))
@ -109,6 +98,7 @@ const (
 	SyncExprs
 	SyncExpr
 	SyncExprType
+	SyncAssign
 	SyncOp
 	SyncFuncLit
 	SyncCompLit
@ -139,4 +129,8 @@ const (
 	SyncStmtsEnd
 	SyncLabel
 	SyncOptLabel
+
+	SyncMultiExpr
+	SyncRType
+	SyncConvRTTI
 )
--- a/src/internal/pkgbits/syncmarker_string.go
+++ b/src/internal/pkgbits/syncmarker_string.go
@ -45,39 +45,40 @@ func _() {
 	_ = x[SyncExprs-35]
 	_ = x[SyncExpr-36]
 	_ = x[SyncExprType-37]
-	_ = x[SyncOp-38]
-	_ = x[SyncFuncLit-39]
-	_ = x[SyncCompLit-40]
-	_ = x[SyncDecl-41]
-	_ = x[SyncFuncBody-42]
-	_ = x[SyncOpenScope-43]
-	_ = x[SyncCloseScope-44]
-	_ = x[SyncCloseAnotherScope-45]
-	_ = x[SyncDeclNames-46]
-	_ = x[SyncDeclName-47]
-	_ = x[SyncStmts-48]
-	_ = x[SyncBlockStmt-49]
-	_ = x[SyncIfStmt-50]
-	_ = x[SyncForStmt-51]
-	_ = x[SyncSwitchStmt-52]
-	_ = x[SyncRangeStmt-53]
-	_ = x[SyncCaseClause-54]
-	_ = x[SyncCommClause-55]
-	_ = x[SyncSelectStmt-56]
-	_ = x[SyncDecls-57]
-	_ = x[SyncLabeledStmt-58]
-	_ = x[SyncUseObjLocal-59]
-	_ = x[SyncAddLocal-60]
-	_ = x[SyncLinkname-61]
-	_ = x[SyncStmt1-62]
-	_ = x[SyncStmtsEnd-63]
-	_ = x[SyncLabel-64]
-	_ = x[SyncOptLabel-65]
+	_ = x[SyncAssign-38]
+	_ = x[SyncOp-39]
+	_ = x[SyncFuncLit-40]
+	_ = x[SyncCompLit-41]
+	_ = x[SyncDecl-42]
+	_ = x[SyncFuncBody-43]
+	_ = x[SyncOpenScope-44]
+	_ = x[SyncCloseScope-45]
+	_ = x[SyncCloseAnotherScope-46]
+	_ = x[SyncDeclNames-47]
+	_ = x[SyncDeclName-48]
+	_ = x[SyncStmts-49]
+	_ = x[SyncBlockStmt-50]
+	_ = x[SyncIfStmt-51]
+	_ = x[SyncForStmt-52]
+	_ = x[SyncSwitchStmt-53]
+	_ = x[SyncRangeStmt-54]
+	_ = x[SyncCaseClause-55]
+	_ = x[SyncCommClause-56]
+	_ = x[SyncSelectStmt-57]
+	_ = x[SyncDecls-58]
+	_ = x[SyncLabeledStmt-59]
+	_ = x[SyncUseObjLocal-60]
+	_ = x[SyncAddLocal-61]
+	_ = x[SyncLinkname-62]
+	_ = x[SyncStmt1-63]
+	_ = x[SyncStmtsEnd-64]
+	_ = x[SyncLabel-65]
+	_ = x[SyncOptLabel-66]
 }

-const _SyncMarker_name = "EOFBoolInt64Uint64StringValueValRelocsRelocUseRelocPublicPosPosBaseObjectObject1PkgPkgDefMethodTypeTypeIdxTypeParamNamesSignatureParamsParamCodeObjSymLocalIdentSelectorPrivateFuncExtVarExtTypeExtPragmaExprListExprsExprAssertTypeOpFuncLitCompLitDeclFuncBodyOpenScopeCloseScopeCloseAnotherScopeDeclNamesDeclNameStmtsBlockStmtIfStmtForStmtSwitchStmtRangeStmtCaseClauseCommClauseSelectStmtDeclsLabeledStmtUseObjLocalAddLocalLinknameStmt1StmtsEndLabelOptLabel"
+const _SyncMarker_name = "EOFBoolInt64Uint64StringValueValRelocsRelocUseRelocPublicPosPosBaseObjectObject1PkgPkgDefMethodTypeTypeIdxTypeParamNamesSignatureParamsParamCodeObjSymLocalIdentSelectorPrivateFuncExtVarExtTypeExtPragmaExprListExprsExprExprTypeAssignOpFuncLitCompLitDeclFuncBodyOpenScopeCloseScopeCloseAnotherScopeDeclNamesDeclNameStmtsBlockStmtIfStmtForStmtSwitchStmtRangeStmtCaseClauseCommClauseSelectStmtDeclsLabeledStmtUseObjLocalAddLocalLinknameStmt1StmtsEndLabelOptLabel"

-var _SyncMarker_index = [...]uint16{0, 3, 7, 12, 18, 24, 29, 32, 38, 43, 51, 57, 60, 67, 73, 80, 83, 89, 95, 99, 106, 120, 129, 135, 140, 147, 150, 160, 168, 175, 182, 188, 195, 201, 209, 214, 218, 228, 230, 237, 244, 248, 256, 265, 275, 292, 301, 309, 314, 323, 329, 336, 346, 355, 365, 375, 385, 390, 401, 412, 420, 428, 433, 441, 446, 454}
+var _SyncMarker_index = [...]uint16{0, 3, 7, 12, 18, 24, 29, 32, 38, 43, 51, 57, 60, 67, 73, 80, 83, 89, 95, 99, 106, 120, 129, 135, 140, 147, 150, 160, 168, 175, 182, 188, 195, 201, 209, 214, 218, 226, 232, 234, 241, 248, 252, 260, 269, 279, 296, 305, 313, 318, 327, 333, 340, 350, 359, 369, 379, 389, 394, 405, 416, 424, 432, 437, 445, 450, 458}

 func (i SyncMarker) String() string {
 	i -= 1
--- a/test/escape_iface.go
+++ b/test/escape_iface.go
@ -234,16 +234,6 @@ func dotTypeEscape2() { // #13805, #15796
 		*(&v) = x.(int)
 		*(&v), *(&ok) = y.(int)
 	}
-	{
-		i := 0
-		j := 0
-		var ok bool
-		var x interface{} = i // ERROR "i does not escape"
-		var y interface{} = j // ERROR "j does not escape"
-
-		sink = x.(int) // ERROR "x.\(int\) escapes to heap"
-		sink, *(&ok) = y.(int)
-	}
 	{
 		i := 0 // ERROR "moved to heap: i"
 		j := 0 // ERROR "moved to heap: j"
--- a/test/escape_iface_nounified.go
+++ b/test/escape_iface_nounified.go
@ -0,0 +1,25 @@
+// errorcheck -0 -m -l
+//go:build !goexperiment.unified
+// +build !goexperiment.unified
+
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package escape
+
+var sink interface{}
+
+func dotTypeEscape2() { // #13805, #15796
+	{
+		i := 0
+		j := 0
+		var ok bool
+		var x interface{} = i // ERROR "i does not escape"
+		var y interface{} = j // ERROR "j does not escape"
+
+		sink = x.(int) // ERROR "x.\(int\) escapes to heap"
+		// BAD: should be "y.\(int\) escapes to heap" too
+		sink, *(&ok) = y.(int)
+	}
+}
--- a/test/escape_iface_unified.go
+++ b/test/escape_iface_unified.go
@ -0,0 +1,24 @@
+// errorcheck -0 -m -l
+//go:build goexperiment.unified
+// +build goexperiment.unified
+
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package escape
+
+var sink interface{}
+
+func dotTypeEscape2() { // #13805, #15796
+	{
+		i := 0
+		j := 0
+		var ok bool
+		var x interface{} = i // ERROR "i does not escape"
+		var y interface{} = j // ERROR "j does not escape"
+
+		sink = x.(int)         // ERROR "x.\(int\) escapes to heap"
+		sink, *(&ok) = y.(int) // ERROR "autotmp_.* escapes to heap"
+	}
+}
--- a/test/fixedbugs/issue27836.dir/Äfoo.go
+++ b/test/fixedbugs/issue27836.dir/Äfoo.go
@ -1,13 +0,0 @@
-package Äfoo
-
-var ÄbarV int = 101
-
-func Äbar(x int) int {
-	defer func() { ÄbarV += 3 }()
-	return Äblix(x)
-}
-
-func Äblix(x int) int {
-	defer func() { ÄbarV += 9 }()
-	return ÄbarV + x
-}
--- a/test/fixedbugs/issue27836.dir/Ämain.go
+++ b/test/fixedbugs/issue27836.dir/Ämain.go
@ -1,13 +0,0 @@
-package main
-
-import (
-	"fmt"
-
-	"./Äfoo"
-	Äblix "./Äfoo"
-)
-
-func main() {
-	fmt.Printf("Äfoo.Äbar(33) returns %v\n", Äfoo.Äbar(33))
-	fmt.Printf("Äblix.Äbar(33) returns %v\n", Äblix.Äbar(33))
-}
--- a/test/fixedbugs/issue27836.dir/Þfoo.go
+++ b/test/fixedbugs/issue27836.dir/Þfoo.go
@ -0,0 +1,17 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package Þfoo
+
+var ÞbarV int = 101
+
+func Þbar(x int) int {
+	defer func() { ÞbarV += 3 }()
+	return Þblix(x)
+}
+
+func Þblix(x int) int {
+	defer func() { ÞbarV += 9 }()
+	return ÞbarV + x
+}
--- a/test/fixedbugs/issue27836.dir/Þmain.go
+++ b/test/fixedbugs/issue27836.dir/Þmain.go
@ -0,0 +1,17 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"fmt"
+
+	"./Þfoo"
+	Þblix "./Þfoo"
+)
+
+func main() {
+	fmt.Printf("Þfoo.Þbar(33) returns %v\n", Þfoo.Þbar(33))
+	fmt.Printf("Þblix.Þbar(33) returns %v\n", Þblix.Þbar(33))
+}
--- a/test/fixedbugs/issue32187.go
+++ b/test/fixedbugs/issue32187.go
@ -36,7 +36,11 @@ func main() {
 		{"type assertion", "", func() { _ = x == x.(*int) }},
 		{"out of bounds", "", func() { _ = x == s[1] }},
 		{"nil pointer dereference #1", "", func() { _ = x == *p }},
-		{"nil pointer dereference #2", "nil pointer dereference", func() { _ = *l == r[0] }},
+		// TODO(mdempsky): Restore "nil pointer dereference" check. The Go
+		// spec doesn't mandate an order for panics (or even panic
+		// messages), but left-to-right is less confusing to users.
+		{"nil pointer dereference #2", "", func() { _ = *l == r[0] }},
+		{"nil pointer dereference #3", "", func() { _ = *l == any(r[0]) }},
 	}

 	for _, tc := range tests {
@ -44,16 +48,14 @@ func main() {
 	}
 }

-func testFuncShouldPanic(name, errStr string, f func()) {
+func testFuncShouldPanic(name, want string, f func()) {
 	defer func() {
 		e := recover()
 		if e == nil {
 			log.Fatalf("%s: comparison did not panic\n", name)
 		}
-		if errStr != "" {
-			if !strings.Contains(e.(error).Error(), errStr) {
-				log.Fatalf("%s: wrong panic message\n", name)
-			}
+		if have := e.(error).Error(); !strings.Contains(have, want) {
+			log.Fatalf("%s: wrong panic message: have %q, want %q\n", name, have, want)
 		}
 	}()
 	f()
--- a/test/fixedbugs/issue42284.dir/b.go
+++ b/test/fixedbugs/issue42284.dir/b.go
@ -7,7 +7,7 @@ package b
 import "./a"

 func g() {
-	h := a.E() // ERROR "inlining call to a.E" "a.I\(a.T\(0\)\) does not escape"
+	h := a.E() // ERROR "inlining call to a.E" "T\(0\) does not escape"
 	h.M()      // ERROR "devirtualizing h.M to a.T"

 	// BAD: T(0) could be stack allocated.
--- a/test/fixedbugs/issue52128.dir/a.go
+++ b/test/fixedbugs/issue52128.dir/a.go
@ -0,0 +1,21 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package a
+
+type I interface{}
+
+type F func()
+
+type s struct {
+	f F
+}
+
+func NewWithF(f F) *s {
+	return &s{f: f}
+}
+
+func NewWithFuncI(func() I) *s {
+	return &s{}
+}
--- a/test/fixedbugs/issue52128.dir/b.go
+++ b/test/fixedbugs/issue52128.dir/b.go
@ -0,0 +1,17 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package b
+
+import (
+	"./a"
+)
+
+type S struct{}
+
+func (s *S) M1() a.I {
+	return a.NewWithF(s.M2)
+}
+
+func (s *S) M2() {}
--- a/test/fixedbugs/issue52128.dir/p.go
+++ b/test/fixedbugs/issue52128.dir/p.go
@ -0,0 +1,14 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package p
+
+import (
+	"./a"
+	"./b"
+)
+
+func f() {
+	a.NewWithFuncI((&b.S{}).M1)
+}
--- a/test/fixedbugs/issue52128.go
+++ b/test/fixedbugs/issue52128.go
@ -0,0 +1,7 @@
+// compiledir
+
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ignored
--- a/test/fixedbugs/issue7921.go
+++ b/test/fixedbugs/issue7921.go
@ -41,7 +41,7 @@ func bufferNoEscape3(xs []string) string { // ERROR "xs does not escape$"

 func bufferNoEscape4() []byte {
 	var b bytes.Buffer
-	b.Grow(64) // ERROR "bufferNoEscape4 ignoring self-assignment in bytes.b.buf = bytes.b.buf\[:bytes.m\]$" "inlining call to bytes.\(\*Buffer\).Grow$" "string\(.*\) escapes to heap"
+	b.Grow(64) // ERROR "bufferNoEscape4 ignoring self-assignment in bytes.b.buf = bytes.b.buf\[:bytes.m\]$" "inlining call to bytes.\(\*Buffer\).Grow$" `".+" escapes to heap`
 	useBuffer(&b)
 	return b.Bytes() // ERROR "inlining call to bytes.\(\*Buffer\).Bytes$"
 }
--- a/test/inline.go
+++ b/test/inline.go
@ -107,18 +107,6 @@ func q(x int) int { // ERROR "can inline q"
 	return foo()                       // ERROR "inlining call to q.func1"
 }

-func r(z int) int {
-	foo := func(x int) int { // ERROR "can inline r.func1" "func literal does not escape"
-		return x + z
-	}
-	bar := func(x int) int { // ERROR "func literal does not escape" "can inline r.func2"
-		return x + func(y int) int { // ERROR "can inline r.func2.1" "can inline r.func3"
-			return 2*y + x*z
-		}(x) // ERROR "inlining call to r.func2.1"
-	}
-	return foo(42) + bar(42) // ERROR "inlining call to r.func1" "inlining call to r.func2" "inlining call to r.func3"
-}
-
 func s0(x int) int { // ERROR "can inline s0"
 	foo := func() { // ERROR "can inline s0.func1" "func literal does not escape"
 		x = x + 1
--- a/test/inline_nounified.go
+++ b/test/inline_nounified.go
@ -0,0 +1,21 @@
+// errorcheckwithauto -0 -m -d=inlfuncswithclosures=1
+//go:build !goexperiment.unified
+// +build !goexperiment.unified
+
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package foo
+
+func r(z int) int {
+	foo := func(x int) int { // ERROR "can inline r.func1" "func literal does not escape"
+		return x + z
+	}
+	bar := func(x int) int { // ERROR "func literal does not escape" "can inline r.func2"
+		return x + func(y int) int { // ERROR "can inline r.func2.1" "can inline r.func3"
+			return 2*y + x*z
+		}(x) // ERROR "inlining call to r.func2.1"
+	}
+	return foo(42) + bar(42) // ERROR "inlining call to r.func1" "inlining call to r.func2" "inlining call to r.func3"
+}
--- a/test/inline_unified.go
+++ b/test/inline_unified.go
@ -0,0 +1,21 @@
+// errorcheckwithauto -0 -m -d=inlfuncswithclosures=1
+//go:build goexperiment.unified
+// +build goexperiment.unified
+
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package foo
+
+func r(z int) int {
+	foo := func(x int) int { // ERROR "can inline r.func1" "func literal does not escape"
+		return x + z
+	}
+	bar := func(x int) int { // ERROR "func literal does not escape" "can inline r.func2"
+		return x + func(y int) int { // ERROR "can inline r.func2.1"
+			return 2*y + x*z
+		}(x) // ERROR "inlining call to r.func2.1"
+	}
+	return foo(42) + bar(42) // ERROR "inlining call to r.func1" "inlining call to r.func2" "can inline r.func3" "inlining call to r.func3"
+}
--- a/test/live_regabi.go
+++ b/test/live_regabi.go
@ -1,4 +1,5 @@
 // errorcheckwithauto -0 -l -live -wb=0 -d=ssa/insert_resched_checks/off
+//go:build (amd64 && goexperiment.regabiargs) || (arm64 && goexperiment.regabiargs)
 // +build amd64,goexperiment.regabiargs arm64,goexperiment.regabiargs

 // Copyright 2014 The Go Authors. All rights reserved.
@ -601,7 +602,7 @@ func f38(b bool) {
 			printnl()
 		case *fi38(2) = <-fc38(): // ERROR "live at call to fc38:( .autotmp_[0-9]+)+$" "live at call to fi38:( .autotmp_[0-9]+)+$" "stack object .autotmp_[0-9]+ string$"
 			printnl()
-		case *fi38(3), *fb38() = <-fc38(): // ERROR "stack object .autotmp_[0-9]+ string$" "live at call to fc38:( .autotmp_[0-9]+)+$" "live at call to fi38:( .autotmp_[0-9]+)+$"
+		case *fi38(3), *fb38() = <-fc38(): // ERROR "stack object .autotmp_[0-9]+ string$" "live at call to f[ibc]38:( .autotmp_[0-9]+)+$"
 			printnl()
 		}
 		printnl()
--- a/test/nilcheck.go
+++ b/test/nilcheck.go
@ -184,6 +184,7 @@ func f4(x *[10]int) {

 func f5(m map[string]struct{}) bool {
 	// Existence-only map lookups should not generate a nil check
-	_, ok := m[""]
+	tmp1, tmp2 := m[""] // ERROR "removed nil check"
+	_, ok := tmp1, tmp2
 	return ok
 }
--- a/test/run.go
+++ b/test/run.go
@ -1980,8 +1980,11 @@ var types2Failures32Bit = setOf(
 )

 var go118Failures = setOf(
-	"typeparam/nested.go",     // 1.18 compiler doesn't support function-local types with generics
-	"typeparam/issue51521.go", // 1.18 compiler produces bad panic message and link error
+	"typeparam/nested.go",      // 1.18 compiler doesn't support function-local types with generics
+	"typeparam/issue51521.go",  // 1.18 compiler produces bad panic message and link error
+	"typeparam/mdempsky/16.go", // 1.18 compiler uses interface shape type in failed type assertions
+	"typeparam/mdempsky/17.go", // 1.18 compiler mishandles implicit conversions from range loops
+	"typeparam/mdempsky/18.go", // 1.18 compiler mishandles implicit conversions in select statements
 )

 // In all of these cases, the 1.17 compiler reports reasonable errors, but either the
@ -2009,18 +2012,10 @@ var _ = setOf(
 )

 var unifiedFailures = setOf(
-	"closure3.go",  // unified IR numbers closures differently than -d=inlfuncswithclosures
-	"escape4.go",   // unified IR can inline f5 and f6; test doesn't expect this
-	"inline.go",    // unified IR reports function literal diagnostics on different lines than -d=inlfuncswithclosures
-	"linkname3.go", // unified IR is missing some linkname errors
+	"closure3.go", // unified IR numbers closures differently than -d=inlfuncswithclosures
+	"escape4.go",  // unified IR can inline f5 and f6; test doesn't expect this

-	"fixedbugs/issue42284.go",  // prints "T(0) does not escape", but test expects "a.I(a.T(0)) does not escape"
-	"fixedbugs/issue7921.go",   // prints "… escapes to heap", but test expects "string(…) escapes to heap"
-	"typeparam/issue47631.go",  // unified IR can handle local type declarations
-	"fixedbugs/issue42058a.go", // unified IR doesn't report channel element too large
-	"fixedbugs/issue42058b.go", // unified IR doesn't report channel element too large
-	"fixedbugs/issue49767.go",  // unified IR doesn't report channel element too large
-	"fixedbugs/issue49814.go",  // unified IR doesn't report array type too large
+	"typeparam/issue47631.go", // unified IR can handle local type declarations
 )

 func setOf(keys ...string) map[string]bool {
--- a/test/switch.go
+++ b/test/switch.go
@ -400,4 +400,18 @@ func main() {
 	case i > x:
 		os.Exit(1)
 	}
+
+	// Unified IR converts the tag and all case values to empty
+	// interface, when any of the case values aren't assignable to the
+	// tag value's type. Make sure that `case nil:` compares against the
+	// tag type's nil value (i.e., `(*int)(nil)`), not nil interface
+	// (i.e., `any(nil)`).
+	switch (*int)(nil) {
+	case nil:
+		// ok
+	case any(nil):
+		assert(false, "case any(nil) matched")
+	default:
+		assert(false, "default matched")
+	}
 }
--- a/test/typeparam/mdempsky/16.go
+++ b/test/typeparam/mdempsky/16.go
@ -0,0 +1,34 @@
+// run
+
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Test that type assertion panics mention the real interface type,
+// not their shape type.
+
+package main
+
+import (
+	"fmt"
+	"runtime"
+	"strings"
+)
+
+func main() {
+	// The exact error message isn't important, but it should mention
+	// `main.T`, not `go.shape.int_0`.
+	if have := F[T](); !strings.Contains(have, "interface { T() main.T }") {
+		fmt.Printf("FAIL: unexpected panic message: %q\n", have)
+	}
+}
+
+type T int
+
+func F[T any]() (res string) {
+	defer func() {
+		res = recover().(runtime.Error).Error()
+	}()
+	_ = interface{ T() T }(nil).(T)
+	return
+}
--- a/test/typeparam/mdempsky/17.go
+++ b/test/typeparam/mdempsky/17.go
@ -0,0 +1,110 @@
+// run
+
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Test that implicit conversions of derived types to interface type
+// in range loops work correctly.
+
+package main
+
+import (
+	"fmt"
+	"reflect"
+)
+
+func main() {
+	test{"int", "V"}.match(RangeArrayAny[V]())
+	test{"int", "V"}.match(RangeArrayIface[V]())
+	test{"V"}.match(RangeChanAny[V]())
+	test{"V"}.match(RangeChanIface[V]())
+	test{"K", "V"}.match(RangeMapAny[K, V]())
+	test{"K", "V"}.match(RangeMapIface[K, V]())
+	test{"int", "V"}.match(RangeSliceAny[V]())
+	test{"int", "V"}.match(RangeSliceIface[V]())
+}
+
+type test []string
+
+func (t test) match(args ...any) {
+	if len(t) != len(args) {
+		fmt.Printf("FAIL: want %v values, have %v\n", len(t), len(args))
+		return
+	}
+	for i, want := range t {
+		if have := reflect.TypeOf(args[i]).Name(); want != have {
+			fmt.Printf("FAIL: %v: want type %v, have %v\n", i, want, have)
+		}
+	}
+}
+
+type iface interface{ M() int }
+
+type K int
+type V int
+
+func (K) M() int { return 0 }
+func (V) M() int { return 0 }
+
+func RangeArrayAny[V any]() (k, v any) {
+	for k, v = range [...]V{zero[V]()} {
+	}
+	return
+}
+
+func RangeArrayIface[V iface]() (k any, v iface) {
+	for k, v = range [...]V{zero[V]()} {
+	}
+	return
+}
+
+func RangeChanAny[V any]() (v any) {
+	for v = range chanOf(zero[V]()) {
+	}
+	return
+}
+
+func RangeChanIface[V iface]() (v iface) {
+	for v = range chanOf(zero[V]()) {
+	}
+	return
+}
+
+func RangeMapAny[K comparable, V any]() (k, v any) {
+	for k, v = range map[K]V{zero[K](): zero[V]()} {
+	}
+	return
+}
+
+func RangeMapIface[K interface {
+	iface
+	comparable
+}, V iface]() (k, v iface) {
+	for k, v = range map[K]V{zero[K](): zero[V]()} {
+	}
+	return
+}
+
+func RangeSliceAny[V any]() (k, v any) {
+	for k, v = range []V{zero[V]()} {
+	}
+	return
+}
+
+func RangeSliceIface[V iface]() (k any, v iface) {
+	for k, v = range []V{zero[V]()} {
+	}
+	return
+}
+
+func chanOf[T any](elems ...T) chan T {
+	c := make(chan T, len(elems))
+	for _, elem := range elems {
+		c <- elem
+	}
+	close(c)
+	return c
+}
+
+func zero[T any]() (_ T) { return }
--- a/test/typeparam/mdempsky/18.go
+++ b/test/typeparam/mdempsky/18.go
@ -0,0 +1,26 @@
+// run
+
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Test that implicit conversions to interface type in a select/case
+// clause are compiled correctly.
+
+package main
+
+import "fmt"
+
+func main() { f[int]() }
+
+func f[T any]() {
+	ch := make(chan T)
+	close(ch)
+
+	var i, ok any
+	select {
+	case i, ok = <-ch:
+	}
+
+	fmt.Printf("%T %T\n", i, ok)
+}
--- a/test/typeparam/mdempsky/18.out
+++ b/test/typeparam/mdempsky/18.out
@ -0,0 +1 @@
+int bool