cmd/compile: fix wrong dict pass condition for type assertions

Fixes #54135

Change-Id: I2b27af8124014b2699ea44bdc765e1fb8f6c8028
Reviewed-on: https://go-review.googlesource.com/c/go/+/420394
Reviewed-by: Keith Randall <khr@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Wayne Zuo <wdvxdr@golangcn.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>

2 files changed, 31 insertions, 0 deletions

diff --git a/src/cmd/compile/internal/noder/stencil.go b/src/cmd/compile/internal/noder/stencil.go
index 280f7cdf1c..d3f51e00cd 100644
--- a/src/cmd/compile/internal/noder/stencil.go
+++ b/src/cmd/compile/internal/noder/stencil.go
@@ -1357,6 +1357,9 @@ func (g *genInst) dictPass(info *instInfo) {
 			}
 		case ir.ODOTTYPE, ir.ODOTTYPE2:
 			dt := m.(*ir.TypeAssertExpr)
+			if dt.Type().IsEmptyInterface() || (dt.Type().IsInterface() && !dt.Type().HasShape()) {
+				break
+			}
 			if !dt.Type().HasShape() && !(dt.X.Type().HasShape() && !dt.X.Type().IsEmptyInterface()) {
 				break
 			}
diff --git a/test/typeparam/issue54135.go b/test/typeparam/issue54135.go
new file mode 100644
index 0000000000..dffef60d0d
--- /dev/null
+++ b/test/typeparam/issue54135.go
@@ -0,0 +1,28 @@
+// compile
+
+// Copyright 2022 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 Foo struct{}
+
+func (Foo) Blanker() {}
+
+type Bar[T any] interface {
+	Blanker()
+}
+
+type Baz interface {
+	Some()
+}
+
+func check[T comparable](p Bar[T]) {
+	_, _ = p.(any)
+	_, _ = p.(Baz)
+}
+
+func main() {
+	check[int](Foo{})
+}