From 4629f6a51da5afabbebe9616f65fbfe0675d6039 Mon Sep 17 00:00:00 2001
From: Matthew Dempsky <mdempsky@google.com>
Date: Mon, 28 Dec 2020 16:14:11 -0800
Subject: [PATCH] [dev.regabi] cmd/compile: merge
 {Selector,CallPart,Method}Expr

These three expression nodes all represent the same syntax, and so
they're represented the same within types2. And also they're not
handled that meaningfully differently throughout the rest of the
compiler to merit unique representations.

Method expressions are somewhat unique today that they're very
frequently turned into plain function names. But eventually that can
be handled by a post-typecheck desugaring phase that reduces the
number of redundant AST forms.

Passes toolstash -cmp.

Change-Id: I20df91bbd0d885c1f18ec67feb61ae1558670719
Reviewed-on: https://go-review.googlesource.com/c/go/+/280636
Trust: Matthew Dempsky <mdempsky@google.com>
Trust: Dan Scales <danscales@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dan Scales <danscales@google.com>
---
 src/cmd/compile/internal/escape/escape.go     |  8 +--
 src/cmd/compile/internal/inline/inl.go        | 11 ++--
 src/cmd/compile/internal/ir/expr.go           | 60 +++++--------------
 src/cmd/compile/internal/ir/fmt.go            | 21 +------
 src/cmd/compile/internal/ir/node_gen.go       | 32 ----------
 src/cmd/compile/internal/staticinit/sched.go  |  8 +--
 src/cmd/compile/internal/typecheck/expr.go    |  6 +-
 src/cmd/compile/internal/typecheck/func.go    | 16 +++--
 src/cmd/compile/internal/typecheck/iexport.go | 21 +------
 .../compile/internal/typecheck/typecheck.go   | 15 ++---
 src/cmd/compile/internal/walk/closure.go      |  4 +-
 src/cmd/compile/internal/walk/complit.go      |  4 +-
 src/cmd/compile/internal/walk/expr.go         |  4 +-
 src/cmd/compile/internal/walk/order.go        |  2 +-
 14 files changed, 58 insertions(+), 154 deletions(-)

diff --git a/src/cmd/compile/internal/escape/escape.go b/src/cmd/compile/internal/escape/escape.go
index d8f0111d2de..7b4037e028b 100644
--- a/src/cmd/compile/internal/escape/escape.go
+++ b/src/cmd/compile/internal/escape/escape.go
@@ -612,10 +612,10 @@ func (e *escape) exprSkipInit(k hole, n ir.Node) {
 		// Flow the receiver argument to both the closure and
 		// to the receiver parameter.
 
-		n := n.(*ir.CallPartExpr)
+		n := n.(*ir.SelectorExpr)
 		closureK := e.spill(k, n)
 
-		m := n.Method
+		m := n.Selection
 
 		// We don't know how the method value will be called
 		// later, so conservatively assume the result
@@ -1542,7 +1542,7 @@ func (e *escape) finish(fns []*ir.Func) {
 					n := n.(*ir.ClosureExpr)
 					n.SetTransient(true)
 				case ir.OCALLPART:
-					n := n.(*ir.CallPartExpr)
+					n := n.(*ir.SelectorExpr)
 					n.SetTransient(true)
 				case ir.OSLICELIT:
 					n := n.(*ir.CompLitExpr)
@@ -1863,7 +1863,7 @@ func HeapAllocReason(n ir.Node) string {
 	if n.Op() == ir.OCLOSURE && typecheck.ClosureType(n.(*ir.ClosureExpr)).Size() >= ir.MaxImplicitStackVarSize {
 		return "too large for stack"
 	}
-	if n.Op() == ir.OCALLPART && typecheck.PartialCallType(n.(*ir.CallPartExpr)).Size() >= ir.MaxImplicitStackVarSize {
+	if n.Op() == ir.OCALLPART && typecheck.PartialCallType(n.(*ir.SelectorExpr)).Size() >= ir.MaxImplicitStackVarSize {
 		return "too large for stack"
 	}
 
diff --git a/src/cmd/compile/internal/inline/inl.go b/src/cmd/compile/internal/inline/inl.go
index 67162771e93..fc6a17b9337 100644
--- a/src/cmd/compile/internal/inline/inl.go
+++ b/src/cmd/compile/internal/inline/inl.go
@@ -419,6 +419,9 @@ func (v *hairyVisitor) doNode(n ir.Node) error {
 
 	case ir.OCALLPART, ir.OSLICELIT:
 		v.budget-- // Hack for toolstash -cmp.
+
+	case ir.OMETHEXPR:
+		v.budget++ // Hack for toolstash -cmp.
 	}
 
 	v.budget--
@@ -613,12 +616,12 @@ func inlCallee(fn ir.Node) *ir.Func {
 	fn = ir.StaticValue(fn)
 	switch fn.Op() {
 	case ir.OMETHEXPR:
-		fn := fn.(*ir.MethodExpr)
+		fn := fn.(*ir.SelectorExpr)
 		n := ir.MethodExprName(fn)
-		// Check that receiver type matches fn.Left.
+		// Check that receiver type matches fn.X.
 		// TODO(mdempsky): Handle implicit dereference
 		// of pointer receiver argument?
-		if n == nil || !types.Identical(n.Type().Recv().Type, fn.T) {
+		if n == nil || !types.Identical(n.Type().Recv().Type, fn.X.Type()) {
 			return nil
 		}
 		return n.Func
@@ -1098,7 +1101,7 @@ func (subst *inlsubst) node(n ir.Node) ir.Node {
 		return n
 
 	case ir.OMETHEXPR:
-		n := n.(*ir.MethodExpr)
+		n := n.(*ir.SelectorExpr)
 		return n
 
 	case ir.OLITERAL, ir.ONIL, ir.OTYPE:
diff --git a/src/cmd/compile/internal/ir/expr.go b/src/cmd/compile/internal/ir/expr.go
index 1337d356a17..872f81a4478 100644
--- a/src/cmd/compile/internal/ir/expr.go
+++ b/src/cmd/compile/internal/ir/expr.go
@@ -225,26 +225,6 @@ func (n *CallExpr) SetOp(op Op) {
 	}
 }
 
-// A CallPartExpr is a method expression X.Method (uncalled).
-type CallPartExpr struct {
-	miniExpr
-	Func     *Func
-	X        Node
-	Method   *types.Field
-	Prealloc *Name
-}
-
-func NewCallPartExpr(pos src.XPos, x Node, method *types.Field, fn *Func) *CallPartExpr {
-	n := &CallPartExpr{Func: fn, X: x, Method: method}
-	n.op = OCALLPART
-	n.pos = pos
-	n.typ = fn.Type()
-	n.Func = fn
-	return n
-}
-
-func (n *CallPartExpr) Sym() *types.Sym { return n.Method.Sym }
-
 // A ClosureExpr is a function literal expression.
 type ClosureExpr struct {
 	miniExpr
@@ -476,24 +456,6 @@ func (n *MakeExpr) SetOp(op Op) {
 	}
 }
 
-// A MethodExpr is a method expression T.M (where T is a type).
-type MethodExpr struct {
-	miniExpr
-	T         *types.Type
-	Method    *types.Field
-	FuncName_ *Name
-}
-
-func NewMethodExpr(pos src.XPos, t *types.Type, method *types.Field) *MethodExpr {
-	n := &MethodExpr{T: t, Method: method}
-	n.pos = pos
-	n.op = OMETHEXPR
-	return n
-}
-
-func (n *MethodExpr) FuncName() *Name { return n.FuncName_ }
-func (n *MethodExpr) Sym() *types.Sym { panic("MethodExpr.Sym") }
-
 // A NilExpr represents the predefined untyped constant nil.
 // (It may be copied and assigned a type, though.)
 type NilExpr struct {
@@ -567,12 +529,13 @@ func NewNameOffsetExpr(pos src.XPos, name *Name, offset int64, typ *types.Type)
 	return n
 }
 
-// A SelectorExpr is a selector expression X.Sym.
+// A SelectorExpr is a selector expression X.Sel.
 type SelectorExpr struct {
 	miniExpr
 	X         Node
 	Sel       *types.Sym
 	Selection *types.Field
+	Prealloc  *Name // preallocated storage for OCALLPART, if any
 }
 
 func NewSelectorExpr(pos src.XPos, op Op, x Node, sel *types.Sym) *SelectorExpr {
@@ -586,7 +549,7 @@ func (n *SelectorExpr) SetOp(op Op) {
 	switch op {
 	default:
 		panic(n.no("SetOp " + op.String()))
-	case ODOT, ODOTPTR, ODOTMETH, ODOTINTER, OXDOT:
+	case OXDOT, ODOT, ODOTPTR, ODOTMETH, ODOTINTER, OCALLPART, OMETHEXPR:
 		n.op = op
 	}
 }
@@ -596,6 +559,16 @@ func (n *SelectorExpr) Implicit() bool     { return n.flags&miniExprImplicit !=
 func (n *SelectorExpr) SetImplicit(b bool) { n.flags.set(miniExprImplicit, b) }
 func (n *SelectorExpr) Offset() int64      { return n.Selection.Offset }
 
+func (n *SelectorExpr) FuncName() *Name {
+	if n.Op() != OMETHEXPR {
+		panic(n.no("FuncName"))
+	}
+	fn := NewNameAt(n.Selection.Pos, MethodSym(n.X.Type(), n.Sel))
+	fn.Class_ = PFUNC
+	fn.SetType(n.Type())
+	return fn
+}
+
 // Before type-checking, bytes.Buffer is a SelectorExpr.
 // After type-checking it becomes a Name.
 func (*SelectorExpr) CanBeNtype() {}
@@ -1089,13 +1062,8 @@ func MethodExprName(n Node) *Name {
 // MethodFunc is like MethodName, but returns the types.Field instead.
 func MethodExprFunc(n Node) *types.Field {
 	switch n.Op() {
-	case ODOTMETH:
+	case ODOTMETH, OMETHEXPR, OCALLPART:
 		return n.(*SelectorExpr).Selection
-	case OMETHEXPR:
-		return n.(*MethodExpr).Method
-	case OCALLPART:
-		n := n.(*CallPartExpr)
-		return n.Method
 	}
 	base.Fatalf("unexpected node: %v (%v)", n, n.Op())
 	panic("unreachable")
diff --git a/src/cmd/compile/internal/ir/fmt.go b/src/cmd/compile/internal/ir/fmt.go
index 49f451a5d85..7680f05ad2b 100644
--- a/src/cmd/compile/internal/ir/fmt.go
+++ b/src/cmd/compile/internal/ir/fmt.go
@@ -630,10 +630,6 @@ func exprFmt(n Node, s fmt.State, prec int) {
 	case OPACK, ONONAME:
 		fmt.Fprint(s, n.Sym())
 
-	case OMETHEXPR:
-		n := n.(*MethodExpr)
-		fmt.Fprint(s, n.FuncName().Sym())
-
 	case ONAMEOFFSET:
 		n := n.(*NameOffsetExpr)
 		fmt.Fprintf(s, "(%v)(%v@%d)", n.Type(), n.Name_, n.Offset_)
@@ -749,16 +745,7 @@ func exprFmt(n Node, s fmt.State, prec int) {
 		n := n.(*StructKeyExpr)
 		fmt.Fprintf(s, "%v:%v", n.Field, n.Value)
 
-	case OCALLPART:
-		n := n.(*CallPartExpr)
-		exprFmt(n.X, s, nprec)
-		if n.Method.Sym == nil {
-			fmt.Fprint(s, ".<nil>")
-			return
-		}
-		fmt.Fprintf(s, ".%s", n.Method.Sym.Name)
-
-	case OXDOT, ODOT, ODOTPTR, ODOTINTER, ODOTMETH:
+	case OXDOT, ODOT, ODOTPTR, ODOTINTER, ODOTMETH, OCALLPART, OMETHEXPR:
 		n := n.(*SelectorExpr)
 		exprFmt(n.X, s, nprec)
 		if n.Sel == nil {
@@ -1160,12 +1147,6 @@ func dumpNode(w io.Writer, n Node, depth int) {
 		}
 		return
 
-	case OMETHEXPR:
-		n := n.(*MethodExpr)
-		fmt.Fprintf(w, "%+v-%+v", n.Op(), n.FuncName().Sym())
-		dumpNodeHeader(w, n)
-		return
-
 	case OASOP:
 		n := n.(*AssignOpStmt)
 		fmt.Fprintf(w, "%+v-%+v", n.Op(), n.AsOp)
diff --git a/src/cmd/compile/internal/ir/node_gen.go b/src/cmd/compile/internal/ir/node_gen.go
index 27a5311748c..a1ce9a4e9dd 100644
--- a/src/cmd/compile/internal/ir/node_gen.go
+++ b/src/cmd/compile/internal/ir/node_gen.go
@@ -209,23 +209,6 @@ func (n *CallExpr) editChildren(edit func(Node) Node) {
 	editList(n.Body, edit)
 }
 
-func (n *CallPartExpr) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
-func (n *CallPartExpr) copy() Node {
-	c := *n
-	c.init = c.init.Copy()
-	return &c
-}
-func (n *CallPartExpr) doChildren(do func(Node) error) error {
-	var err error
-	err = maybeDoList(n.init, err, do)
-	err = maybeDo(n.X, err, do)
-	return err
-}
-func (n *CallPartExpr) editChildren(edit func(Node) Node) {
-	editList(n.init, edit)
-	n.X = maybeEdit(n.X, edit)
-}
-
 func (n *CaseClause) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
 func (n *CaseClause) copy() Node {
 	c := *n
@@ -655,21 +638,6 @@ func (n *MapType) editChildren(edit func(Node) Node) {
 	n.Elem = maybeEdit(n.Elem, edit)
 }
 
-func (n *MethodExpr) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
-func (n *MethodExpr) copy() Node {
-	c := *n
-	c.init = c.init.Copy()
-	return &c
-}
-func (n *MethodExpr) doChildren(do func(Node) error) error {
-	var err error
-	err = maybeDoList(n.init, err, do)
-	return err
-}
-func (n *MethodExpr) editChildren(edit func(Node) Node) {
-	editList(n.init, edit)
-}
-
 func (n *Name) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) }
 func (n *Name) copy() Node                    { panic("Name.copy") }
 func (n *Name) doChildren(do func(Node) error) error {
diff --git a/src/cmd/compile/internal/staticinit/sched.go b/src/cmd/compile/internal/staticinit/sched.go
index 2711f6cec0a..d8f51766dee 100644
--- a/src/cmd/compile/internal/staticinit/sched.go
+++ b/src/cmd/compile/internal/staticinit/sched.go
@@ -104,7 +104,7 @@ func (s *Schedule) staticcopy(l *ir.Name, loff int64, rn *ir.Name, typ *types.Ty
 
 	switch r.Op() {
 	case ir.OMETHEXPR:
-		r = r.(*ir.MethodExpr).FuncName()
+		r = r.(*ir.SelectorExpr).FuncName()
 		fallthrough
 	case ir.ONAME:
 		r := r.(*ir.Name)
@@ -165,7 +165,7 @@ func (s *Schedule) staticcopy(l *ir.Name, loff int64, rn *ir.Name, typ *types.Ty
 			}
 			x := e.Expr
 			if x.Op() == ir.OMETHEXPR {
-				x = x.(*ir.MethodExpr).FuncName()
+				x = x.(*ir.SelectorExpr).FuncName()
 			}
 			if x.Op() == ir.ONAME && s.staticcopy(l, loff+e.Xoffset, x.(*ir.Name), typ) {
 				continue
@@ -195,7 +195,7 @@ func (s *Schedule) StaticAssign(l *ir.Name, loff int64, r ir.Node, typ *types.Ty
 		return s.staticcopy(l, loff, r, typ)
 
 	case ir.OMETHEXPR:
-		r := r.(*ir.MethodExpr)
+		r := r.(*ir.SelectorExpr)
 		return s.staticcopy(l, loff, r.FuncName(), typ)
 
 	case ir.ONIL:
@@ -461,7 +461,7 @@ func StaticLoc(n ir.Node) (name *ir.Name, offset int64, ok bool) {
 		return n, 0, true
 
 	case ir.OMETHEXPR:
-		n := n.(*ir.MethodExpr)
+		n := n.(*ir.SelectorExpr)
 		return StaticLoc(n.FuncName())
 
 	case ir.ODOT:
diff --git a/src/cmd/compile/internal/typecheck/expr.go b/src/cmd/compile/internal/typecheck/expr.go
index 3e7a880c2a4..0682548c273 100644
--- a/src/cmd/compile/internal/typecheck/expr.go
+++ b/src/cmd/compile/internal/typecheck/expr.go
@@ -626,10 +626,8 @@ func tcDot(n *ir.SelectorExpr, top int) ir.Node {
 	}
 
 	if (n.Op() == ir.ODOTINTER || n.Op() == ir.ODOTMETH) && top&ctxCallee == 0 {
-		// Create top-level function.
-		fn := makepartialcall(n)
-
-		return ir.NewCallPartExpr(n.Pos(), n.X, n.Selection, fn)
+		n.SetOp(ir.OCALLPART)
+		n.SetType(MethodValueWrapper(n).Type())
 	}
 	return n
 }
diff --git a/src/cmd/compile/internal/typecheck/func.go b/src/cmd/compile/internal/typecheck/func.go
index ed4f3ad4fe9..c58fef10ecd 100644
--- a/src/cmd/compile/internal/typecheck/func.go
+++ b/src/cmd/compile/internal/typecheck/func.go
@@ -91,7 +91,7 @@ func ClosureType(clo *ir.ClosureExpr) *types.Type {
 // PartialCallType returns the struct type used to hold all the information
 // needed in the closure for n (n must be a OCALLPART node).
 // The address of a variable of the returned type can be cast to a func.
-func PartialCallType(n *ir.CallPartExpr) *types.Type {
+func PartialCallType(n *ir.SelectorExpr) *types.Type {
 	t := types.NewStruct(types.NoPkg, []*types.Field{
 		types.NewField(base.Pos, Lookup("F"), types.Types[types.TUINTPTR]),
 		types.NewField(base.Pos, Lookup("R"), n.X.Type()),
@@ -247,9 +247,17 @@ func closurename(outerfunc *ir.Func) *types.Sym {
 // globClosgen is like Func.Closgen, but for the global scope.
 var globClosgen int32
 
-// makepartialcall returns a DCLFUNC node representing the wrapper function (*-fm) needed
-// for partial calls.
-func makepartialcall(dot *ir.SelectorExpr) *ir.Func {
+// MethodValueWrapper returns the DCLFUNC node representing the
+// wrapper function (*-fm) needed for the given method value. If the
+// wrapper function hasn't already been created yet, it's created and
+// added to Target.Decls.
+//
+// TODO(mdempsky): Move into walk. This isn't part of type checking.
+func MethodValueWrapper(dot *ir.SelectorExpr) *ir.Func {
+	if dot.Op() != ir.OCALLPART {
+		base.Fatalf("MethodValueWrapper: unexpected %v (%v)", dot, dot.Op())
+	}
+
 	t0 := dot.Type()
 	meth := dot.Sel
 	rcvrtype := dot.X.Type()
diff --git a/src/cmd/compile/internal/typecheck/iexport.go b/src/cmd/compile/internal/typecheck/iexport.go
index 3b071a61abb..e35cbcafa25 100644
--- a/src/cmd/compile/internal/typecheck/iexport.go
+++ b/src/cmd/compile/internal/typecheck/iexport.go
@@ -1252,17 +1252,6 @@ func (w *exportWriter) expr(n ir.Node) {
 		w.pos(n.Pos())
 		w.value(n.Type(), n.Val())
 
-	case ir.OMETHEXPR:
-		// Special case: explicit name of func (*T) method(...) is turned into pkg.(*T).method,
-		// but for export, this should be rendered as (*pkg.T).meth.
-		// These nodes have the special property that they are names with a left OTYPE and a right ONAME.
-		n := n.(*ir.MethodExpr)
-		w.op(ir.OXDOT)
-		w.pos(n.Pos())
-		w.op(ir.OTYPE)
-		w.typ(n.T) // n.Left.Op == OTYPE
-		w.selector(n.Method.Sym)
-
 	case ir.ONAME:
 		// Package scope name.
 		n := n.(*ir.Name)
@@ -1336,15 +1325,7 @@ func (w *exportWriter) expr(n ir.Node) {
 	// case OSTRUCTKEY:
 	//	unreachable - handled in case OSTRUCTLIT by elemList
 
-	case ir.OCALLPART:
-		// An OCALLPART is an OXDOT before type checking.
-		n := n.(*ir.CallPartExpr)
-		w.op(ir.OXDOT)
-		w.pos(n.Pos())
-		w.expr(n.X)
-		w.selector(n.Method.Sym)
-
-	case ir.OXDOT, ir.ODOT, ir.ODOTPTR, ir.ODOTINTER, ir.ODOTMETH:
+	case ir.OXDOT, ir.ODOT, ir.ODOTPTR, ir.ODOTINTER, ir.ODOTMETH, ir.OCALLPART, ir.OMETHEXPR:
 		n := n.(*ir.SelectorExpr)
 		w.op(ir.OXDOT)
 		w.pos(n.Pos())
diff --git a/src/cmd/compile/internal/typecheck/typecheck.go b/src/cmd/compile/internal/typecheck/typecheck.go
index e23c249ff2b..ff9178b5972 100644
--- a/src/cmd/compile/internal/typecheck/typecheck.go
+++ b/src/cmd/compile/internal/typecheck/typecheck.go
@@ -1176,19 +1176,16 @@ func typecheckMethodExpr(n *ir.SelectorExpr) (res ir.Node) {
 		return n
 	}
 
-	me := ir.NewMethodExpr(n.Pos(), n.X.Type(), m)
-	me.SetType(NewMethodType(m.Type, n.X.Type()))
-	f := NewName(ir.MethodSym(t, m.Sym))
-	f.Class_ = ir.PFUNC
-	f.SetType(me.Type())
-	me.FuncName_ = f
+	n.SetOp(ir.OMETHEXPR)
+	n.Selection = m
+	n.SetType(NewMethodType(m.Type, n.X.Type()))
 
 	// Issue 25065. Make sure that we emit the symbol for a local method.
 	if base.Ctxt.Flag_dynlink && !inimport && (t.Sym() == nil || t.Sym().Pkg == types.LocalPkg) {
-		NeedFuncSym(me.FuncName_.Sym())
+		NeedFuncSym(n.FuncName().Sym())
 	}
 
-	return me
+	return n
 }
 
 func derefall(t *types.Type) *types.Type {
@@ -1422,7 +1419,7 @@ notenough:
 			// Method expressions have the form T.M, and the compiler has
 			// rewritten those to ONAME nodes but left T in Left.
 			if call.Op() == ir.OMETHEXPR {
-				call := call.(*ir.MethodExpr)
+				call := call.(*ir.SelectorExpr)
 				base.Errorf("not enough arguments in call to method expression %v%s", call, details)
 			} else {
 				base.Errorf("not enough arguments in call to %v%s", call, details)
diff --git a/src/cmd/compile/internal/walk/closure.go b/src/cmd/compile/internal/walk/closure.go
index 30f86f0965a..9bcb82bc036 100644
--- a/src/cmd/compile/internal/walk/closure.go
+++ b/src/cmd/compile/internal/walk/closure.go
@@ -151,7 +151,7 @@ func walkClosure(clo *ir.ClosureExpr, init *ir.Nodes) ir.Node {
 	return walkExpr(cfn, init)
 }
 
-func walkCallPart(n *ir.CallPartExpr, init *ir.Nodes) ir.Node {
+func walkCallPart(n *ir.SelectorExpr, init *ir.Nodes) ir.Node {
 	// Create closure in the form of a composite literal.
 	// For x.M with receiver (x) type T, the generated code looks like:
 	//
@@ -176,7 +176,7 @@ func walkCallPart(n *ir.CallPartExpr, init *ir.Nodes) ir.Node {
 
 	clos := ir.NewCompLitExpr(base.Pos, ir.OCOMPLIT, ir.TypeNode(typ).(ir.Ntype), nil)
 	clos.SetEsc(n.Esc())
-	clos.List = []ir.Node{ir.NewUnaryExpr(base.Pos, ir.OCFUNC, n.Func.Nname), n.X}
+	clos.List = []ir.Node{ir.NewUnaryExpr(base.Pos, ir.OCFUNC, typecheck.MethodValueWrapper(n).Nname), n.X}
 
 	addr := typecheck.NodAddr(clos)
 	addr.SetEsc(n.Esc())
diff --git a/src/cmd/compile/internal/walk/complit.go b/src/cmd/compile/internal/walk/complit.go
index 8c4f9583ef5..fadcd87f258 100644
--- a/src/cmd/compile/internal/walk/complit.go
+++ b/src/cmd/compile/internal/walk/complit.go
@@ -539,7 +539,7 @@ func anylit(n ir.Node, var_ ir.Node, init *ir.Nodes) {
 		appendWalkStmt(init, ir.NewAssignStmt(base.Pos, var_, n))
 
 	case ir.OMETHEXPR:
-		n := n.(*ir.MethodExpr)
+		n := n.(*ir.SelectorExpr)
 		anylit(n.FuncName(), var_, init)
 
 	case ir.OPTRLIT:
@@ -666,7 +666,7 @@ func genAsStatic(as *ir.AssignStmt) {
 		staticdata.InitConst(name, offset, r, int(r.Type().Width))
 		return
 	case ir.OMETHEXPR:
-		r := r.(*ir.MethodExpr)
+		r := r.(*ir.SelectorExpr)
 		staticdata.InitFunc(name, offset, r.FuncName())
 		return
 	case ir.ONAME:
diff --git a/src/cmd/compile/internal/walk/expr.go b/src/cmd/compile/internal/walk/expr.go
index fd0dd5b0624..7cc67580248 100644
--- a/src/cmd/compile/internal/walk/expr.go
+++ b/src/cmd/compile/internal/walk/expr.go
@@ -100,7 +100,7 @@ func walkExpr1(n ir.Node, init *ir.Nodes) ir.Node {
 
 	case ir.OMETHEXPR:
 		// TODO(mdempsky): Do this right after type checking.
-		n := n.(*ir.MethodExpr)
+		n := n.(*ir.SelectorExpr)
 		return n.FuncName()
 
 	case ir.ONOT, ir.ONEG, ir.OPLUS, ir.OBITNOT, ir.OREAL, ir.OIMAG, ir.OSPTR, ir.OITAB, ir.OIDATA:
@@ -306,7 +306,7 @@ func walkExpr1(n ir.Node, init *ir.Nodes) ir.Node {
 		return walkClosure(n.(*ir.ClosureExpr), init)
 
 	case ir.OCALLPART:
-		return walkCallPart(n.(*ir.CallPartExpr), init)
+		return walkCallPart(n.(*ir.SelectorExpr), init)
 	}
 
 	// No return! Each case must return (or panic),
diff --git a/src/cmd/compile/internal/walk/order.go b/src/cmd/compile/internal/walk/order.go
index ebbd4675701..0dd76ccee9a 100644
--- a/src/cmd/compile/internal/walk/order.go
+++ b/src/cmd/compile/internal/walk/order.go
@@ -1310,7 +1310,7 @@ func (o *orderState) expr1(n, lhs ir.Node) ir.Node {
 		return n
 
 	case ir.OCALLPART:
-		n := n.(*ir.CallPartExpr)
+		n := n.(*ir.SelectorExpr)
 		n.X = o.expr(n.X, nil)
 		if n.Transient() {
 			t := typecheck.PartialCallType(n)