Fix zombiezen-sqlite-migrate panic on anonymous interfaces

Fixes zombiezen#29

Author: zombiezen

cmd/zombiezen-sqlite-migrate/migrate.go

@@ -402,7 +402,9 @@ func process(pkg *packages.Package, file *ast.File) []error {
 				}
 				if sig, ok := obj.Type().(*types.Signature); ok {
 					if recv := sig.Recv(); recv != nil {
-						sym.typeName = depointerType(recv.Type()).(*types.Named).Obj().Name()
+						if named, ok := depointerType(recv.Type()).(*types.Named); ok {
+							sym.typeName = named.Obj().Name()
+						}
 					}
 				}
 				if newSym := symbolRewrites[sym]; newSym.name != "" {

cmd/zombiezen-sqlite-migrate/testdata/TestProcess/AnonymousInterface/original.go

@@ -0,0 +1,11 @@
+// Copyright 2021 Ross Light
+// SPDX-License-Identifier: ISC
+
+package main
+
+func main() {
+	var foo interface {
+		Bar()
+	}
+	_ = foo
+}

cmd/zombiezen-sqlite-migrate/testdata/TestProcess/AnonymousInterface/want.go

@@ -0,0 +1,11 @@
+// Copyright 2021 Ross Light
+// SPDX-License-Identifier: ISC
+
+package main
+
+func main() {
+	var foo interface {
+		Bar()
+	}
+	_ = foo
+}