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https://github.com/golang/go
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ddb5a42b25
Agressively mark all LHS variables in assignments as used if there is any error in the (entire) assignment. This reduces the number of spurious "declared but not used" errors in programs that are invalid in the first place. This behavior is closer to the behavior of the compiler's original type checker (types1) and lets us remove lines of the form "_ = variable" just to satisfy test cases. It also makes more important errors visible by not crowding them out. Remove the Checker.useLHS function and use Checker.use instead: useLHS didn't evaluate top-level variables, but we actually want them to be evaluated in an error scenario so that they are getting used (and thus we don't get the "declared but not used" error). Fixes #42937. Change-Id: Idda460f6b81c66735bf9fd597c54188949bf12b8 Reviewed-on: https://go-review.googlesource.com/c/go/+/351730 Trust: Robert Griesemer <gri@golang.org> Run-TryBot: Robert Griesemer <gri@golang.org> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Robert Findley <rfindley@google.com>
38 lines
758 B
Go
38 lines
758 B
Go
// errorcheck
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// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Test that interface{M()} = *interface{M()} produces a compiler error.
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// Does not compile.
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package main
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type Inst interface {
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Next() *Inst
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}
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type Regexp struct {
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code []Inst
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start Inst
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}
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type Start struct {
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foo *Inst
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}
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func (start *Start) Next() *Inst { return nil }
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func AddInst(Inst) *Inst {
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print("ok in addinst\n")
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return nil
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}
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func main() {
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print("call addinst\n")
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var x Inst = AddInst(new(Start)) // ERROR "pointer to interface|incompatible type"
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print("return from addinst\n")
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var y *Inst = new(Start) // ERROR "pointer to interface|incompatible type"
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}
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