go/test/cannotassign.go
Robert Griesemer 72ad2f44ea [dev.typeparams] test: add scaffolding to run.go to check compiler with -G flag
Added a new flag -G to run. Setting -G (as in: go run run.go -G)
will run tests marked with "errorcheck" (and no other flags) also
with the compiler using the new typechecker.

Many tests don't pass yet (due to discrepancies in error messages).
The top-level tests in the test directory which don't pass yet have
been explicitly excluded, permitting to see the current status.
Future CLs will bring error messages in sync and eventually all
tests should pass.

Change-Id: I7caf5eff413e173f68d092af4bbe458434718d74
Reviewed-on: https://go-review.googlesource.com/c/go/+/274313
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2020-12-01 21:49:31 +00:00

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Go

// 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.
// Test "cannot assign" errors
package main
func main() {
var s string = "hello"
s[1:2] = "a" // ERROR "cannot assign to .* (\(strings are immutable\))?"
s[3] = "b" // ERROR "cannot assign to .* (\(strings are immutable\))?"
const n int = 1
const cs string = "hello"
n = 2 // ERROR "cannot assign to .* (\(declared const\))?"
cs = "hi" // ERROR "cannot assign to .* (\(declared const\))?"
true = false // ERROR "cannot assign to .* (\(declared const\))?"
var m map[int]struct{ n int }
m[0].n = 7 // ERROR "cannot assign to struct field .* in map$"
1 = 7 // ERROR "cannot assign to 1"
"hi" = 7 // ERROR `cannot assign to "hi"`
nil = 7 // ERROR "cannot assign to nil"
len("") = 7 // ERROR `cannot assign to len\(""\)`
[]int{} = nil // ERROR "cannot assign to \[\]int\{\}"
var x int = 7
x + 1 = 7 // ERROR "cannot assign to x \+ 1"
}