cmd/compile: fix dictionaries for nested closures

Capturing dictionary closure variables is ok.

Fixes #47684

Change-Id: I049c87117915e0c5a172b9665bfac2f91064b2d4
Reviewed-on: https://go-review.googlesource.com/c/go/+/342050
Trust: Keith Randall <khr@golang.org>
Trust: Dan Scales <danscales@google.com>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dan Scales <danscales@google.com>

3 files changed, 61 insertions, 0 deletions

diff --git a/test/typeparam/issue47684.go b/test/typeparam/issue47684.go
new file mode 100644
index 0000000000..2798b78ca8
--- /dev/null
+++ b/test/typeparam/issue47684.go
@@ -0,0 +1,19 @@
+// run -gcflags=-G=3
+
+// Copyright 2021 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
+
+func f[G any]() int {
+	return func() int {
+		return func() int {
+			return 0
+		}()
+	}()
+}
+
+func main() {
+	f[int]()
+}
diff --git a/test/typeparam/issue47684b.go b/test/typeparam/issue47684b.go
new file mode 100644
index 0000000000..c43ef8d169
--- /dev/null
+++ b/test/typeparam/issue47684b.go
@@ -0,0 +1,23 @@
+// run -gcflags=-G=3
+
+// Copyright 2021 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
+
+func f[G any]() interface{} {
+	return func() interface{} {
+		return func() interface{} {
+			var x G
+			return x
+		}()
+	}()
+}
+
+func main() {
+	x := f[int]()
+	if v, ok := x.(int); !ok || v != 0 {
+		panic("bad")
+	}
+}
diff --git a/test/typeparam/issue47684c.go b/test/typeparam/issue47684c.go
new file mode 100644
index 0000000000..32f1b66087
--- /dev/null
+++ b/test/typeparam/issue47684c.go
@@ -0,0 +1,19 @@
+// run -gcflags=-G=3
+
+// Copyright 2021 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
+
+func f[G any]() func()func()int {
+	return func() func()int {
+		return func() int {
+			return 0
+		}
+	}
+}
+
+func main() {
+	f[int]()()()
+}