cmd/compile: put constant value on node inside parentheses

That's where the unified IR writer expects it.

Fixes #73476

Change-Id: Ic22bd8dee5be5991e6d126ae3f6eccb2acdc0b19
Reviewed-on: https://go-review.googlesource.com/c/go/+/667415
Reviewed-by: Junyang Shao <shaojunyang@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Keith Randall <khr@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Keith Randall <khr@google.com>

diff --git a/src/cmd/compile/internal/types2/range.go b/src/cmd/compile/internal/types2/range.go
index ecda53d14bad45f768d5de715fc3fc05db6e63e1..dc0d81d05b7bec11bb0d55866e14b436ed0d672f 100644 (file)
--- a/src/cmd/compile/internal/types2/range.go
+++ b/src/cmd/compile/internal/types2/range.go
@@ -37,6 +37,16 @@ func (check *Checker) rangeStmt(inner stmtContext, rangeStmt *syntax.ForStmt, no
 
        if isTypes2 && x.mode != invalid && sValue == nil && !check.hasCallOrRecv {
                if t, ok := arrayPtrDeref(under(x.typ)).(*Array); ok {
+                       for {
+                               // Put constant info on the thing inside parentheses.
+                               // That's where (*../noder/writer).expr expects it.
+                               // See issue 73476.
+                               p, ok := rangeVar.(*syntax.ParenExpr)
+                               if !ok {
+                                       break
+                               }
+                               rangeVar = p.X
+                       }
                        // Override type of rangeVar to be a constant
                        // (and thus side-effects will not be computed
                        // by the backend).

diff --git a/src/go/types/range.go b/src/go/types/range.go
index 91149c1426fe8c59663131f1290b2553664a8dac..ed7d83283c5fb6ca2aa7395c181801642bb2792a 100644 (file)
--- a/src/go/types/range.go
+++ b/src/go/types/range.go
@@ -40,6 +40,16 @@ func (check *Checker) rangeStmt(inner stmtContext, rangeStmt *ast.RangeStmt, noN
 
        if isTypes2 && x.mode != invalid && sValue == nil && !check.hasCallOrRecv {
                if t, ok := arrayPtrDeref(under(x.typ)).(*Array); ok {
+                       for {
+                               // Put constant info on the thing inside parentheses.
+                               // That's where (*../noder/writer).expr expects it.
+                               // See issue 73476.
+                               p, ok := rangeVar.(*ast.ParenExpr)
+                               if !ok {
+                                       break
+                               }
+                               rangeVar = p.X
+                       }
                        // Override type of rangeVar to be a constant
                        // (and thus side-effects will not be computed
                        // by the backend).

diff --git a/test/fixedbugs/issue73476.go b/test/fixedbugs/issue73476.go
new file mode 100644 (file)
index 0000000..cc54d9c
--- /dev/null
+++ b/test/fixedbugs/issue73476.go
@@ -0,0 +1,17 @@
+// run
+
+// Copyright 2025 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
+
+//go:noinline
+func f(p *[4]int) {
+       for i := range (*p) { // Note the parentheses! gofmt wants to remove them - don't let it!
+               println(i)
+       }
+}
+func main() {
+       f(nil)
+}

diff --git a/test/fixedbugs/issue73476.out b/test/fixedbugs/issue73476.out
new file mode 100644 (file)
index 0000000..bc856da
--- /dev/null
+++ b/test/fixedbugs/issue73476.out
@@ -0,0 +1,4 @@
+0
+1
+2
+3