Migration: implement support for user-definable prefix expressions.

stereotype441 · commit-bot@chromium.org · commit fc7049ae7dea · 2019-07-02T10:23:21.000Z
Change-Id: Ie2316625d8ed6fd9ab3aee3b592ce5b82b0cb1e8 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/107750 Commit-Queue: Paul Berry <paulberry@google.com> Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
diff --git a/pkg/nnbd_migration/lib/src/edge_builder.dart b/pkg/nnbd_migration/lib/src/edge_builder.dart
@@ -690,8 +690,7 @@ $stackTrace''');
 
   @override
   DecoratedType visitPrefixExpression(PrefixExpression node) {
-    /* DecoratedType operandType = */
-    _handleAssignment(node.operand, _notNullType);
+    var targetType = _handleAssignment(node.operand, _notNullType);
     var operatorType = node.operator.type;
     if (operatorType == TokenType.BANG) {
       return _nonNullableBoolType;
@@ -711,10 +710,11 @@ $stackTrace''');
       var calleeType = getOrComputeElementType(callee);
       // TODO(paulberry): substitute if necessary
       return calleeType.returnType;
+    } else {
+      var callee = node.staticElement;
+      var calleeType = getOrComputeElementType(callee, targetType: targetType);
+      return _handleInvocationArguments(node, [], null, calleeType, null);
     }
-    // TODO(brianwilkerson) The remaining cases are invocations.
-    _unimplemented(
-        node, 'Prefix expression with operator ${node.operator.lexeme}');
   }
 
   @override
diff --git a/pkg/nnbd_migration/test/api_test.dart b/pkg/nnbd_migration/test/api_test.dart
@@ -1727,6 +1727,42 @@ int f(int x, int Function(int i) g) {
     await _checkSingleFileChanges(content, expected);
   }
 
+  test_prefix_minus() async {
+    var content = '''
+class C {
+  D operator-() => null;
+}
+class D {}
+D test(C c) => -c;
+''';
+    var expected = '''
+class C {
+  D? operator-() => null;
+}
+class D {}
+D? test(C c) => -c;
+''';
+    await _checkSingleFileChanges(content, expected);
+  }
+
+  test_prefix_minus_substitute() async {
+    var content = '''
+abstract class C<T> {
+  D<T> operator-();
+}
+class D<U> {}
+D<int> test(C<int/*?*/> c) => -c;
+''';
+    var expected = '''
+abstract class C<T> {
+  D<T> operator-();
+}
+class D<U> {}
+D<int?> test(C<int?/*?*/> c) => -c;
+''';
+    await _checkSingleFileChanges(content, expected);
+  }
+
   test_prefixExpression_bang() async {
     var content = '''
 bool f(bool b) => !b;
diff --git a/pkg/nnbd_migration/test/edge_builder_test.dart b/pkg/nnbd_migration/test/edge_builder_test.dart
@@ -1979,6 +1979,20 @@ bool f(bool b) {
     assertEdge(never, return_f, hard: false);
   }
 
+  test_prefixExpression_minus() async {
+    await analyze('''
+abstract class C {
+  C operator-();
+}
+C test(C c) => -c/*check*/;
+''');
+    assertEdge(decoratedTypeAnnotation('C operator').node,
+        decoratedTypeAnnotation('C test').node,
+        hard: false);
+    assertNullCheck(checkExpression('c/*check*/'),
+        assertEdge(decoratedTypeAnnotation('C c').node, never, hard: true));
+  }
+
   test_prefixExpression_minusMinus() async {
     await analyze('''
 int f(int i) {
