diff --git a/unused/testdata/src/alias/alias.go b/unused/testdata/src/alias/alias.go
index 5d05524db..af296600e 100644
--- a/unused/testdata/src/alias/alias.go
+++ b/unused/testdata/src/alias/alias.go
@@ -1,5 +1,7 @@
 package main
 
+import "net/http"
+
 type t1 struct{} // used
 type t2 struct{} // unused
 type t3 struct{} // used
@@ -13,3 +15,20 @@ func main() { // used
 	var _ alias1
 	var _ t3
 }
+
+type t4 struct { // used
+	x int // used
+}
+
+func (t4) foo() {} // used
+
+//lint:ignore U1000 alias5 is ignored, which also ignores t4
+type alias5 = t4 // used
+
+//lint:ignore U1000 alias6 is ignored, and we don't incorrectly try to include http.Server's fields and methods in the graph
+type alias6 = http.Server // used
+
+//lint:ignore U1000 aliases don't have to be to named types
+type alias7 = struct { // used
+	x int // used
+}
diff --git a/unused/unused.go b/unused/unused.go
index 3b1ed1702..fd51d381d 100644
--- a/unused/unused.go
+++ b/unused/unused.go
@@ -1206,6 +1206,17 @@ func (g *graph) entry(pkg *pkg) {
 
 					// use methods and fields of ignored types
 					if obj, ok := obj.(*types.TypeName); ok {
+						if obj.IsAlias() {
+							if typ, ok := obj.Type().(*types.Named); ok && typ.Obj().Pkg() != obj.Pkg() {
+								// This is an alias of a named type in another package.
+								// Don't walk its fields or methods; we don't have to,
+								// and it breaks an assertion in graph.use because we're using an object that we haven't seen before.
+								//
+								// For aliases to types in the same package, we do want to ignore the fields and methods,
+								// because ignoring the alias should ignore the aliased type.
+								continue
+							}
+						}
 						if typ, ok := obj.Type().(*types.Named); ok {
 							for i := 0; i < typ.NumMethods(); i++ {
 								g.use(typ.Method(i), nil, edgeIgnored)