go/test/fixedbugs/issue11354.go
Josh Bleecher Snyder 8dafdb1be1 cmd/compile: add Type.WidthCalculated
Prior to this CL, Type.Width != 0 was the mark
of a Type whose Width had been calculated.
As a result, dowidth always recalculated
the width of struct{}.
This, combined with the prohibition on calculating
the width of a FuncArgsStruct and the use of
struct{} as a function argument,
meant that there were circumstances in which
it was forbidden to call dowidth on a type.
This inhibits refactoring to call dowidth automatically,
rather than explicitly.
Instead add a helper method, Type.WidthCalculated,
and implement as Type.Align > 0.
Type.Width is not a good candidate for tracking
whether the width has been calculated;
0 is a value type width, and Width is subject to
too much magic value game-playing.

For good measure, add a test for #11354.

Change-Id: Ie9a9fb5d924e7a2010c1904ae5e38ed4a38eaeb2
Reviewed-on: https://go-review.googlesource.com/38468
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-03-28 18:06:09 +00:00

16 lines
262 B
Go

// compile
// 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.
package main
type X int
var foo = map[int]X{}
var bar = map[int][8]X{}
func main() {}