go/test/fixedbugs/issue19482.go
Josh Bleecher Snyder c9446398e8 cmd/compile: allow composite literal structs with _ fields
Given code such as

type T struct {
  _ string
}

func f() {
  var x = T{"space"}
  // ...
}

the compiler rewrote the 'var x' line as

var x T
x._ = "space"

The compiler then rejected the assignment to
a blank field, thus rejecting valid code.

It also failed to catch a number of invalid assignments.
And there were insufficient checks for validity
when emitting static data, leading to ICEs.

To fix, check earlier for explicit blanks field names,
explicitly handle legit blanks in sinit,
and don't try to emit static data for nodes
for which typechecking has failed.

Fixes #19482

Change-Id: I594476171d15e6e8ecc6a1749e3859157fe2c929
Reviewed-on: https://go-review.googlesource.com/38006
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-04-07 22:01:18 +00:00

35 lines
793 B
Go

// errorcheck
// Copyright 2017 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.
// Compiler rejected initialization of structs to composite literals
// in a non-static setting (e.g. in a function)
// when the struct contained a field named _.
package p
type T struct {
_ string
}
func ok() {
var x = T{"check"}
_ = x
_ = T{"et"}
}
var (
y = T{"stare"}
w = T{_: "look"} // ERROR "invalid field name _ in struct initializer"
_ = T{"page"}
_ = T{_: "out"} // ERROR "invalid field name _ in struct initializer"
)
func bad() {
var z = T{_: "verse"} // ERROR "invalid field name _ in struct initializer"
_ = z
_ = T{_: "itinerary"} // ERROR "invalid field name _ in struct initializer"
}