Issue 25914. Fix for compound assignments like 'T += T'.

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 1fdfc1e93c29bef864cfa1b664962428ca02ada8..34ff1098aeb6b9a97573f66ea9dfe178de2f69a7 100644
--- a/pkg/analyzer/test/src/task/strong/inferred_type_test.dart
+++ b/pkg/analyzer/test/src/task/strong/inferred_type_test.dart
@@ -3039,6 +3039,12 @@ class Point<T extends num> {
   Point<T> operator *(Point<T> other) {
     return new Point<T>(x * other.x, y * other.y);
   }
+
+  void compoundAssignment(T k) {
+    x += k;
+    x -= k;
+    x *= k;
+  }
 }
   ''');
   }