cmd/compile: avoid checkwidth of [...] arrays

Fixes #20333

Change-Id: I0653cc859076f146d8ea8f5bd55cb22b0b8d987f
Reviewed-on: https://go-review.googlesource.com/43290
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/cmd/compile/internal/gc/typecheck.go b/src/cmd/compile/internal/gc/typecheck.go
index 6f544a5b9aee43c32dcea7990d36db7654501d9a..5e92e926e3d95449c75ebb9aa51b0daef7a9b9c5 100644 (file)
--- a/src/cmd/compile/internal/gc/typecheck.go
+++ b/src/cmd/compile/internal/gc/typecheck.go
@@ -498,7 +498,12 @@ OpSwitch:
                        ok |= Etype
                        n.Op = OTYPE
                        n.Type = types.NewPtr(l.Type)
-                       checkwidth(l.Type) // ensure this gets dowidth'd for the backend
+                       // Ensure l.Type gets dowidth'd for the backend. Issue 20174.
+                       // Don't checkwidth [...] arrays, though, since they
+                       // will be replaced by concrete-sized arrays. Issue 20333.
+                       if !l.Type.IsDDDArray() {
+                               checkwidth(l.Type)
+                       }
                        n.Left = nil
                        break OpSwitch
                }

diff --git a/test/fixedbugs/issue20333.go b/test/fixedbugs/issue20333.go
new file mode 100644 (file)
index 0000000..8202ab3
--- /dev/null
+++ b/test/fixedbugs/issue20333.go
@@ -0,0 +1,15 @@
+// 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.
+
+// Issue 20333: early checkwidth of [...] arrays led to compilation errors.
+
+package main
+
+import "fmt"
+
+func main() {
+       fmt.Println(&[...]string{"abc", "def", "ghi"})
+}