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cmd/compile: clearer error when non-bool used as "||" and "&&" operand

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Fixes #41500

Change-Id: I658d8921b7769b6e4288ca781cbdca5ff14a84ee
Reviewed-on: https://go-review.googlesource.com/c/go/+/255899
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This commit is contained in:
Cuong Manh Le 2020-09-21 12:00:24 +07:00
parent 8860251db8
commit 23573d0ea2
2 changed files with 36 additions and 0 deletions
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16
src/cmd/compile/internal/gc/typecheck.go
View file

@ -630,6 +630,22 @@ func typecheck1(n *Node, top int) (res *Node) {
break
}
// For "x == x && len(s)", it's better to report that "len(s)" (type int)
// can't be used with "&&" than to report that "x == x" (type untyped bool)
// can't be converted to int (see issue #41500).
if n.Op == OANDAND || n.Op == OOROR {
if !n.Left.Type.IsBoolean() {
yyerror("invalid operation: %v (operator %v not defined on %s)", n, n.Op, typekind(n.Left.Type))
n.Type = nil
return n
}
if !n.Right.Type.IsBoolean() {
yyerror("invalid operation: %v (operator %v not defined on %s)", n, n.Op, typekind(n.Right.Type))
n.Type = nil
return n
}
}
// ideal mixed with non-ideal
l, r = defaultlit2(l, r, false)

20
test/fixedbugs/issue41500.go Normal file
View file

@ -0,0 +1,20 @@
// errorcheck
// Copyright 2020 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
type s struct {
slice []int
}
func f() {
var x *s
_ = x == nil || len(x.slice) // ERROR "invalid operation: .+ \(operator \|\| not defined on int\)"
_ = len(x.slice) || x == nil // ERROR "invalid operation: .+ \(operator \|\| not defined on int\)"
_ = x == nil && len(x.slice) // ERROR "invalid operation: .+ \(operator && not defined on int\)"
_ = len(x.slice) && x == nil // ERROR "invalid operation: .+ \(operator && not defined on int\)"
}