Issue 25914. Refine type of 'T + T' when 'T extends num' to 'T' in strong mode.

pkg/analyzer/test/src/task/strong/inferred_type_test.dart

Index: pkg/analyzer/test/src/task/strong/inferred_type_test.dart
diff --git a/pkg/analyzer/test/src/task/strong/inferred_type_test.dart b/pkg/analyzer/test/src/task/strong/inferred_type_test.dart
index 38b37cbe8f155e74252983a8020782a3c773c9b1..cf5f6578da53146eb5fc17f6020f28f7d409015f 100644
--- a/pkg/analyzer/test/src/task/strong/inferred_type_test.dart
+++ b/pkg/analyzer/test/src/task/strong/inferred_type_test.dart
@@ -2104,6 +2104,29 @@ var y = new C().m(1, b: 'bbb', c: 2.0);
     expect(unit.topLevelVariables[0].type.toString(), 'double');
   }
 
+  void test_refineBinaryExpressionType_typeParameter() {
+    checkFile('''
+class Point<T extends num> {
+  T x;
+  T y;
+
+  Point(this.x, this.y);
+
+  Point<T> operator +(Point<T> other) {
+    return new Point<T>(x + other.x, y + other.y);
+  }
+
+  Point<T> operator -(Point<T> other) {
+    return new Point<T>(x - other.x, y - other.y);
+  }
+
+  Point<T> operator *(Point<T> other) {
+    return new Point<T>(x * other.x, y * other.y);
+  }
+}
+  ''');
+  }
+
   void test_inferGenericMethodType_positional() {
     var unit = checkFile('''
 class C {