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396b6c2e7c
The assignment type-checking code previously bounced around a lot between the LHS and RHS sides of the assignment. But there's actually a very simple, consistent pattern to how to type check assignments: 1. Check the RHS expression. 2. If the LHS expression is an identifier that was declared in this statement and it doesn't have an explicit type, give it the RHS expression's default type. 3. Check the LHS expression. 4. Try assigning the RHS expression to the LHS expression, adding implicit conversions as needed. This CL implements this algorithm, and refactors tcAssign and tcAssignList to use a common implementation. It also fixes the error messages to consistently say just "1 variable" or "1 value", rather than occasionally "1 variables" or "1 values". Fixes #43348. Passes toolstash -cmp. Change-Id: I749cb8d6ccbc7d22cd7cb0a381f58a39fc2696b5 Reviewed-on: https://go-review.googlesource.com/c/go/+/280112 Trust: Matthew Dempsky <mdempsky@google.com> Run-TryBot: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
15 lines
629 B
Go
15 lines
629 B
Go
// errorcheck
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// Copyright 2019 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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package main
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func main() {
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var a, b = 1 // ERROR "assignment mismatch: 2 variables but 1 value|wrong number of initializations"
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_ = 1, 2 // ERROR "assignment mismatch: 1 variable but 2 values|number of variables does not match"
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c, d := 1 // ERROR "assignment mismatch: 2 variables but 1 value|wrong number of initializations"
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e, f := 1, 2, 3 // ERROR "assignment mismatch: 2 variables but 3 values|wrong number of initializations"
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}
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