diff --git a/src/cmd/compile/internal/importer/iimport.go b/src/cmd/compile/internal/importer/iimport.go
index b61b1e97fb7..7f7143dcfe7 100644
--- a/src/cmd/compile/internal/importer/iimport.go
+++ b/src/cmd/compile/internal/importer/iimport.go
@@ -318,17 +318,17 @@ func (r *importReader) obj(name string) {
 		r.declare(types2.NewFunc(pos, r.currPkg, name, sig))
 
 	case 'T', 'U':
-		var tparams []*types2.TypeParam
-		if tag == 'U' {
-			tparams = r.tparamList()
-		}
-
 		// Types can be recursive. We need to setup a stub
 		// declaration before recursing.
 		obj := types2.NewTypeName(pos, r.currPkg, name, nil)
 		named := types2.NewNamed(obj, nil, nil)
-		named.SetTypeParams(tparams)
+		// Declare obj before calling r.tparamList, so the new type name is recognized
+		// if used in the constraint of one of its own typeparams (see #48280).
 		r.declare(obj)
+		if tag == 'U' {
+			tparams := r.tparamList()
+			named.SetTypeParams(tparams)
+		}
 
 		underlying := r.p.typAt(r.uint64(), named).Underlying()
 		named.SetUnderlying(underlying)
diff --git a/test/typeparam/issue48280.dir/a.go b/test/typeparam/issue48280.dir/a.go
new file mode 100644
index 00000000000..17859e6aa90
--- /dev/null
+++ b/test/typeparam/issue48280.dir/a.go
@@ -0,0 +1,11 @@
+// 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 I[T I[T]] interface {
+	F() T
+}
+
+type S struct{}
diff --git a/test/typeparam/issue48280.dir/main.go b/test/typeparam/issue48280.dir/main.go
new file mode 100644
index 00000000000..b9981c6f61a
--- /dev/null
+++ b/test/typeparam/issue48280.dir/main.go
@@ -0,0 +1,11 @@
+// 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 "a"
+
+func main() {
+	_ = a.S{}
+}
diff --git a/test/typeparam/issue48280.go b/test/typeparam/issue48280.go
new file mode 100644
index 00000000000..76930e5e4f6
--- /dev/null
+++ b/test/typeparam/issue48280.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