cmd/compile: mark ODYNAMICDOTTYPE as an expression that can panic

Fixes #47924

Change-Id: I4325b3c4ed9d369d9ea778478285436e1b2ab08a
Reviewed-on: https://go-review.googlesource.com/c/go/+/344571
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>

diff --git a/src/cmd/compile/internal/walk/walk.go b/src/cmd/compile/internal/walk/walk.go
index 6551fe7a645310ac09df4147eaff07c3f1bb5f41..a9bbc9a54f66708abbf1c84bfa4c12ac12df1b21 100644 (file)
--- a/src/cmd/compile/internal/walk/walk.go
+++ b/src/cmd/compile/internal/walk/walk.go
@@ -312,7 +312,7 @@ func mayCall(n ir.Node) bool {
                        return true
 
                case ir.OINDEX, ir.OSLICE, ir.OSLICEARR, ir.OSLICE3, ir.OSLICE3ARR, ir.OSLICESTR,
-                       ir.ODEREF, ir.ODOTPTR, ir.ODOTTYPE, ir.ODIV, ir.OMOD, ir.OSLICE2ARRPTR:
+                       ir.ODEREF, ir.ODOTPTR, ir.ODOTTYPE, ir.ODYNAMICDOTTYPE, ir.ODIV, ir.OMOD, ir.OSLICE2ARRPTR:
                        // These ops might panic, make sure they are done
                        // before we start marshaling args for a call. See issue 16760.
                        return true

diff --git a/test/typeparam/issue47924.go b/test/typeparam/issue47924.go
new file mode 100644 (file)
index 0000000..1d1bab3
--- /dev/null
+++ b/test/typeparam/issue47924.go
@@ -0,0 +1,15 @@
+// compile -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 p
+
+type Cache[K any] struct{}
+
+func (c Cache[K]) foo(x interface{}, f func(K) bool) {
+       f(x.(K))
+}
+
+var _ Cache[int]