diff --git a/src/cmd/compile/internal/reflectdata/reflect.go b/src/cmd/compile/internal/reflectdata/reflect.go
index ce41b8c934..d396c249e4 100644
--- a/src/cmd/compile/internal/reflectdata/reflect.go
+++ b/src/cmd/compile/internal/reflectdata/reflect.go
@@ -959,11 +959,6 @@ func writeType(t *types.Type) *obj.LSym {
 		base.Fatalf("unresolved defined type: %v", tbase)
 	}
 
-	dupok := 0
-	if tbase.Sym() == nil || tbase.HasShape() { // TODO(mdempsky): Probably need DUPOK for instantiated types too.
-		dupok = obj.DUPOK
-	}
-
 	if !NeedEmit(tbase) {
 		if i := typecheck.BaseTypeIndex(t); i >= 0 {
 			lsym.Pkg = tbase.Sym().Pkg.Prefix
@@ -1196,7 +1191,9 @@ func writeType(t *types.Type) *obj.LSym {
 	}
 
 	ot = dextratypeData(lsym, ot, t)
-	objw.Global(lsym, int32(ot), int16(dupok|obj.RODATA))
+	objw.Global(lsym, int32(ot), int16(obj.DUPOK|obj.RODATA))
+	// Note: DUPOK is required to ensure that we don't end up with more
+	// than one type descriptor for a given type.
 
 	// The linker will leave a table of all the typelinks for
 	// types in the binary, so the runtime can find them.
diff --git a/test/typeparam/issue49241.dir/a.go b/test/typeparam/issue49241.dir/a.go
new file mode 100644
index 0000000000..34c99657d4
--- /dev/null
+++ b/test/typeparam/issue49241.dir/a.go
@@ -0,0 +1,13 @@
+// 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 T[P any] struct {
+	x P
+}
+
+type U struct {
+	a,b int
+}
diff --git a/test/typeparam/issue49241.dir/b.go b/test/typeparam/issue49241.dir/b.go
new file mode 100644
index 0000000000..45c1afbaf1
--- /dev/null
+++ b/test/typeparam/issue49241.dir/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 "a"
+
+//go:noinline
+func F() interface {} {
+	return a.T[int]{}
+}
+
+//go:noinline
+func G() interface{} {
+	return struct{X,Y a.U}{}
+}
diff --git a/test/typeparam/issue49241.dir/c.go b/test/typeparam/issue49241.dir/c.go
new file mode 100644
index 0000000000..ea3bab2954
--- /dev/null
+++ b/test/typeparam/issue49241.dir/c.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 c
+
+import "a"
+
+//go:noinline
+func F() interface {} {
+	return a.T[int]{}
+}
+
+//go:noinline
+func G() interface{} {
+	return struct{X,Y a.U}{}
+}
diff --git a/test/typeparam/issue49241.dir/main.go b/test/typeparam/issue49241.dir/main.go
new file mode 100644
index 0000000000..7c8a8b1acd
--- /dev/null
+++ b/test/typeparam/issue49241.dir/main.go
@@ -0,0 +1,21 @@
+// 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 (
+	"b"
+	"c"
+)
+
+func main() {
+	if b.G() != c.G() {
+		println(b.G(), c.G())
+		panic("bad")
+	}
+	if b.F() != c.F() {
+		println(b.F(), c.F())
+		panic("bad")
+	}
+}
diff --git a/test/typeparam/issue49241.go b/test/typeparam/issue49241.go
new file mode 100644
index 0000000000..76930e5e4f
--- /dev/null
+++ b/test/typeparam/issue49241.go
@@ -0,0 +1,7 @@
+// rundir -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 ignored