1 files changed, 27 insertions, 0 deletions
diff --git a/test/typeparam/issue39755.go b/test/typeparam/issue39755.go
new file mode 100644
index 0000000000..c4b6902eea
--- /dev/null
+++ b/test/typeparam/issue39755.go
@@ -0,0 +1,27 @@
+// compile -G=3
+
+// Copyright 2020 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.
+
+// copied from cmd/compile/internal/types2/testdata/fixedbugs/issue39755.go
+
+package p
+
+func _[T interface{ ~map[string]int }](x T) {
+	_ = x == nil
+}
+
+// simplified test case from issue
+
+type PathParamsConstraint interface {
+	~map[string]string | ~[]struct{ key, value string }
+}
+
+type PathParams[T PathParamsConstraint] struct {
+	t T
+}
+
+func (pp *PathParams[T]) IsNil() bool {
+	return pp.t == nil // this must succeed
+}