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[dev.regabi] go/types: type alias decl requires go1.9

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This is a port of CL 289570 to go/types. It has some notable differences
with that CL:
 + A new _BadDecl error code is added, to indicate declarations with bad
   syntax.
 + declInfo is updated hold not an 'alias' bool, but an aliasPos
   token.Pos to identify the location of the type aliasing '=' token.
   This allows for error messages to be accurately placed on the '='

For #31793

Change-Id: Ib15969f9cd5be30228b7a4c6406f978d6fc58018
Reviewed-on: https://go-review.googlesource.com/c/go/+/291318
Trust: Robert Findley <rfindley@google.com>
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
This commit is contained in:
Rob Findley 2021-02-11 10:45:49 -05:00 committed by Robert Findley
parent c2358a1ae7
commit 7696c94334
4 changed files with 30 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
src/go/types/decl.go
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@ -189,7 +189,7 @@ func (check *Checker) objDecl(obj Object, def *Named) {
check.varDecl(obj, d.lhs, d.typ, d.init)
case *TypeName:
// invalid recursive types are detected via path
check.typeDecl(obj, d.typ, def, d.alias)
check.typeDecl(obj, d.typ, def, d.aliasPos)
case *Func:
// functions may be recursive - no need to track dependencies
check.funcDecl(obj, d)
@ -234,7 +234,7 @@ func (check *Checker) cycle(obj Object) (isCycle bool) {
// this information explicitly in the object.
var alias bool
if d := check.objMap[obj]; d != nil {
alias = d.alias // package-level object
alias = d.aliasPos.IsValid() // package-level object
} else {
alias = obj.IsAlias() // function local object
}
@ -640,14 +640,17 @@ func (n *Named) setUnderlying(typ Type) {
}
}
func (check *Checker) typeDecl(obj *TypeName, typ ast.Expr, def *Named, alias bool) {
func (check *Checker) typeDecl(obj *TypeName, typ ast.Expr, def *Named, aliasPos token.Pos) {
assert(obj.typ == nil)
check.later(func() {
check.validType(obj.typ, nil)
})
if alias {
if aliasPos.IsValid() {
if !check.allowVersion(obj.pkg, 1, 9) {
check.errorf(atPos(aliasPos), _BadDecl, "type aliases requires go1.9 or later")
}
obj.typ = Typ[Invalid]
obj.typ = check.typ(typ)
@ -678,9 +681,12 @@ func (check *Checker) typeDecl(obj *TypeName, typ ast.Expr, def *Named, alias bo
}
// TODO(rFindley): move to the callsite, as this is only needed for top-level
// decls.
check.addMethodDecls(obj)
}
// TODO(rFindley): rename to collectMethods, to be consistent with types2.
func (check *Checker) addMethodDecls(obj *TypeName) {
// get associated methods
// (Checker.collectObjects only collects methods with non-blank names;
@ -691,7 +697,7 @@ func (check *Checker) addMethodDecls(obj *TypeName) {
return
}
delete(check.methods, obj)
assert(!check.objMap[obj].alias) // don't use TypeName.IsAlias (requires fully set up object)
assert(!check.objMap[obj].aliasPos.IsValid()) // don't use TypeName.IsAlias (requires fully set up object)
// use an objset to check for name conflicts
var mset objset
@ -864,7 +870,7 @@ func (check *Checker) declStmt(d ast.Decl) {
check.declare(check.scope, d.spec.Name, obj, scopePos)
// mark and unmark type before calling typeDecl; its type is still nil (see Checker.objDecl)
obj.setColor(grey + color(check.push(obj)))
check.typeDecl(obj, d.spec.Type, nil, d.spec.Assign.IsValid())
check.typeDecl(obj, d.spec.Type, nil, d.spec.Assign)
check.pop().setColor(black)
default:
check.invalidAST(d.node(), "unknown ast.Decl node %T", d.node())

3
src/go/types/errorcodes.go
View File

@ -1366,4 +1366,7 @@ const (
// return i
// }
_InvalidGo
// _BadDecl occurs when a declaration has invalid syntax.
_BadDecl
)

8
src/go/types/resolver.go
View File

@ -23,7 +23,7 @@ type declInfo struct {
init ast.Expr // init/orig expression, or nil
inherited bool // if set, the init expression is inherited from a previous constant declaration
fdecl *ast.FuncDecl // func declaration, or nil
alias bool // type alias declaration
aliasPos token.Pos // If valid, the decl is a type alias and aliasPos is the position of '='.
// The deps field tracks initialization expression dependencies.
deps map[Object]bool // lazily initialized
@ -366,7 +366,7 @@ func (check *Checker) collectObjects() {
}
case typeDecl:
obj := NewTypeName(d.spec.Name.Pos(), pkg, d.spec.Name.Name, nil)
check.declarePkgObj(d.spec.Name, obj, &declInfo{file: fileScope, typ: d.spec.Type, alias: d.spec.Assign.IsValid()})
check.declarePkgObj(d.spec.Name, obj, &declInfo{file: fileScope, typ: d.spec.Type, aliasPos: d.spec.Assign})
case funcDecl:
info := &declInfo{file: fileScope, fdecl: d.decl}
name := d.decl.Name.Name
@ -493,7 +493,7 @@ func (check *Checker) resolveBaseTypeName(typ ast.Expr) (ptr bool, base *TypeNam
// we're done if tdecl defined tname as a new type
// (rather than an alias)
tdecl := check.objMap[tname] // must exist for objects in package scope
if !tdecl.alias {
if !tdecl.aliasPos.IsValid() {
return ptr, tname
}
@ -534,7 +534,7 @@ func (check *Checker) packageObjects() {
// phase 1
for _, obj := range objList {
// If we have a type alias, collect it for the 2nd phase.
if tname, _ := obj.(*TypeName); tname != nil && check.objMap[tname].alias {
if tname, _ := obj.(*TypeName); tname != nil && check.objMap[tname].aliasPos.IsValid() {
aliasList = append(aliasList, tname)
continue
}

11
src/go/types/testdata/go1_8.src vendored Normal file
View File

@ -0,0 +1,11 @@
// 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.
// Check Go language version-specific errors.
package go1_8 // go1.8
// type alias declarations
type any = /* ERROR type aliases requires go1.9 or later */ interface{}