languages/go
languages/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-09-15 22:20:06 +00:00
Code Issues Packages Projects Releases Wiki Activity

cmd/compile/internal/types2: better error message for invalid array decls

Browse source 
Fixes #43527.

Change-Id: I988a4d49f2f54b4b1741688fb52a55bf313d39e1
Reviewed-on: https://go-review.googlesource.com/c/go/+/348731
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
This commit is contained in:
Robert Griesemer 2021-09-08 22:08:14 -07:00
parent da1aa65053
commit 5a94a90d84
4 changed files with 52 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

16
src/cmd/compile/internal/types2/testdata/fixedbugs/issue43527.go2 vendored Normal file
View file

@ -0,0 +1,16 @@
// 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.
package p
const L = 10
type (
_ [L]struct{}
_ [A /* ERROR undeclared name A for array length */ ]struct{}
_ [B /* ERROR not an expression */ ]struct{}
_[A any] struct{}
B int
)

10
src/cmd/compile/internal/types2/typexpr.go
View file

@ -428,6 +428,14 @@ func (check *Checker) instantiatedType(x syntax.Expr, targsx []syntax.Expr, def
// and returns the constant length >= 0, or a value < 0
// to indicate an error (and thus an unknown length).
func (check *Checker) arrayLength(e syntax.Expr) int64 {
// If e is an undeclared identifier, the array declaration might be an
// attempt at a parameterized type declaration with missing constraint.
// Provide a better error message than just "undeclared name: X".
if name, _ := e.(*syntax.Name); name != nil && check.lookup(name.Value) == nil {
check.errorf(name, "undeclared name %s for array length", name.Value)
return -1
}
var x operand
check.expr(&x, e)
if x.mode != constant_ {
@ -436,6 +444,7 @@ func (check *Checker) arrayLength(e syntax.Expr) int64 {
}
return -1
}
if isUntyped(x.typ) || isInteger(x.typ) {
if val := constant.ToInt(x.val); val.Kind() == constant.Int {
if representableConst(val, check, Typ[Int], nil) {
@ -447,6 +456,7 @@ func (check *Checker) arrayLength(e syntax.Expr) int64 {
}
}
}
check.errorf(&x, "array length %s must be integer", &x)
return -1
}

16
src/go/types/testdata/fixedbugs/issue43527.go2 vendored Normal file
View file

@ -0,0 +1,16 @@
// 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.
package p
const L = 10
type (
_ [L]struct{}
_ [A /* ERROR undeclared name A for array length */ ]struct{}
_ [B /* ERROR not an expression */ ]struct{}
_[A any] struct{}
B int
)

10
src/go/types/typexpr.go
View file

@ -412,6 +412,14 @@ func (check *Checker) instantiatedType(x ast.Expr, targsx []ast.Expr, def *Named
// and returns the constant length >= 0, or a value < 0
// to indicate an error (and thus an unknown length).
func (check *Checker) arrayLength(e ast.Expr) int64 {
// If e is an undeclared identifier, the array declaration might be an
// attempt at a parameterized type declaration with missing constraint.
// Provide a better error message than just "undeclared name: X".
if name, _ := e.(*ast.Ident); name != nil && check.lookup(name.Name) == nil {
check.errorf(name, _InvalidArrayLen, "undeclared name %s for array length", name.Name)
return -1
}
var x operand
check.expr(&x, e)
if x.mode != constant_ {
@ -420,6 +428,7 @@ func (check *Checker) arrayLength(e ast.Expr) int64 {
}
return -1
}
if isUntyped(x.typ) || isInteger(x.typ) {
if val := constant.ToInt(x.val); val.Kind() == constant.Int {
if representableConst(val, check, Typ[Int], nil) {
@ -431,6 +440,7 @@ func (check *Checker) arrayLength(e ast.Expr) int64 {
}
}
}
check.errorf(&x, _InvalidArrayLen, "array length %s must be integer", &x)
return -1
}