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489f508ccf
The syntax for go and defer specifies an arbitrary expression, not a call; the call requirement is spelled out in prose. Don't to the call check in the parser; instead move it to the type checker. This is simpler and also allows the type checker to check expressions that are not calls, and avoid "not used" errors due to such expressions. We would like to make the same change in go/parser and go/types but the change requires Go/DeferStmt nodes to hold an ast.Expr rather than an *ast.CallExpr. We cannot change that for backward- compatibility reasons. Since we don't test this behavior for the type checkers alone (only for the compiler), we get away with it for now. Follow-up on CL 425675 which introduced the extra errors in the first place. Change-Id: I90890b3079d249bdeeb76d5673246ba44bec1a7b Reviewed-on: https://go-review.googlesource.com/c/go/+/425794 Reviewed-by: Robert Griesemer <gri@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Robert Griesemer <gri@google.com> Auto-Submit: Robert Griesemer <gri@google.com> Reviewed-by: Alan Donovan <adonovan@google.com>
25 lines
629 B
Go
25 lines
629 B
Go
// errorcheck
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// Copyright 2018 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 we type-check deferred/go functions even
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// if they are not called (a common error). Specifically,
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// we don't want to see errors such as import or variable
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// declared but not used.
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package p
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import (
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"fmt"
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"math"
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)
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func f() {
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var i int
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defer func() { fmt.Println() } // ERROR "must be function call"
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go func() { _ = math.Sin(0) } // ERROR "must be function call"
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go func() { _ = i} // ERROR "must be function call"
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}
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