4 files changed, 54 insertions, 0 deletions
diff --git a/misc/cgo/testshared/shared_test.go b/misc/cgo/testshared/shared_test.go
index 5e0893784b..f52391c6f6 100644
--- a/misc/cgo/testshared/shared_test.go
+++ b/misc/cgo/testshared/shared_test.go
@@ -1063,3 +1063,11 @@ func TestGCData(t *testing.T) {
 	goCmd(t, "build", "-linkshared", "./gcdata/main")
 	runWithEnv(t, "running gcdata/main", []string{"GODEBUG=clobberfree=1"}, "./main")
 }
+
+// Test that we don't decode type symbols from shared libraries (which has no data,
+// causing panic). See issue 44031.
+func TestIssue44031(t *testing.T) {
+	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./issue44031/a")
+	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./issue44031/b")
+	goCmd(t, "run", "-linkshared", "./issue44031/main")
+}
diff --git a/misc/cgo/testshared/testdata/issue44031/a/a.go b/misc/cgo/testshared/testdata/issue44031/a/a.go
new file mode 100644
index 0000000000..48827e682f
--- /dev/null
+++ b/misc/cgo/testshared/testdata/issue44031/a/a.go
@@ -0,0 +1,9 @@
+// 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 a
+
+type ATypeWithALoooooongName interface { // a long name, so the type descriptor symbol name is mangled
+	M()
+}
diff --git a/misc/cgo/testshared/testdata/issue44031/b/b.go b/misc/cgo/testshared/testdata/issue44031/b/b.go
new file mode 100644
index 0000000000..ad3ebec2b9
--- /dev/null
+++ b/misc/cgo/testshared/testdata/issue44031/b/b.go
@@ -0,0 +1,17 @@
+// 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 b
+
+import "testshared/issue44031/a"
+
+type T int
+
+func (T) M() {}
+
+var i = a.ATypeWithALoooooongName(T(0))
+
+func F() {
+	i.M()
+}
diff --git a/misc/cgo/testshared/testdata/issue44031/main/main.go b/misc/cgo/testshared/testdata/issue44031/main/main.go
new file mode 100644
index 0000000000..47f2e3a98e
--- /dev/null
+++ b/misc/cgo/testshared/testdata/issue44031/main/main.go
@@ -0,0 +1,20 @@
+// 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
+
+import "testshared/issue44031/b"
+
+type t int
+
+func (t) m() {}
+
+type i interface{ m() } // test that unexported method is correctly marked
+
+var v interface{} = t(0)
+
+func main() {
+	b.F()
+	v.(i).m()
+}