[analyzer] Dot shorthands: Avoid crashing with prefix and postfix operators.

When we evaluate the `target` for this `IndexExpression`, we don't cache the  dot shorthand context which causes the analyzer to crash. Added a context push of the `target` (whose context is `UnknownType`) which allows the analyzer to error out without crashing.

Passing co19 tests and unit tests.

Bug: #59835
Change-Id: I6a19b3e92ed803a51d0cfd320df886a26a36b33d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/426289
Commit-Queue: Kallen Tu <[email protected]>
Reviewed-by: Chloe Stefantsova <[email protected]>

Author: kallentu

pkg/analyzer/lib/src/generated/resolver.dart

@@ -1455,10 +1455,14 @@ class ResolverVisitor extends ThrowingAstVisitor<void>
     if (node is IndexExpressionImpl) {
       var target = node.target;
       if (target != null) {
-        analyzeExpression(
-          target,
-          SharedTypeSchemaView(UnknownInferredType.instance),
-        );
+        if (isDotShorthand(node)) {
+          // Recovery.
+          // It's a compile-time error to use postfix or prefix operators with
+          // dot shorthands. We provide an unknown type since this shouldn't be
+          // valid code, but we want to prevent any crashes.
+          pushDotShorthandContext(target, operations.unknownType);
+        }
+        analyzeExpression(target, operations.unknownType);
         popRewrite();
       }
 

pkg/analyzer/test/src/dart/resolution/dot_shorthand_constructor_invocation_test.dart

@@ -2,6 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'package:analyzer/src/dart/error/syntactic_errors.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
@@ -566,6 +567,40 @@ DotShorthandConstructorInvocation
 ''');
   }
 
+  test_postfixOperator() async {
+    await assertErrorsInCode(
+      r'''
+class C {}
+
+void main() {
+  C c = .new()++;
+  print(c);
+}
+''',
+      [
+        error(CompileTimeErrorCode.DOT_SHORTHAND_UNDEFINED_INVOCATION, 35, 3),
+        error(ParserErrorCode.ILLEGAL_ASSIGNMENT_TO_NON_ASSIGNABLE, 40, 2),
+      ],
+    );
+  }
+
+  test_prefixOperator() async {
+    await assertErrorsInCode(
+      r'''
+class C {}
+
+void main() {
+  C c = ++.new();
+  print(c);
+}
+''',
+      [
+        error(CompileTimeErrorCode.DOT_SHORTHAND_UNDEFINED_INVOCATION, 37, 3),
+        error(ParserErrorCode.MISSING_ASSIGNABLE_SELECTOR, 41, 1),
+      ],
+    );
+  }
+
   test_requiredParameters_missing() async {
     await assertErrorsInCode(
       r'''

pkg/analyzer/test/src/dart/resolution/dot_shorthand_invocation_test.dart

@@ -2,6 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'package:analyzer/src/dart/error/syntactic_errors.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
@@ -619,6 +620,48 @@ DotShorthandInvocation
 ''');
   }
 
+  test_postfixOperator() async {
+    await assertErrorsInCode(
+      r'''
+class C {
+  static C member() => C(1);
+  int x;
+  C(this.x);
+}
+
+void main() {
+  C c = .member()++;
+  print(c);
+}
+''',
+      [
+        error(CompileTimeErrorCode.DOT_SHORTHAND_UNDEFINED_INVOCATION, 87, 6),
+        error(ParserErrorCode.ILLEGAL_ASSIGNMENT_TO_NON_ASSIGNABLE, 95, 2),
+      ],
+    );
+  }
+
+  test_prefixOperator() async {
+    await assertErrorsInCode(
+      r'''
+class C {
+  static C member() => C(1);
+  int x;
+  C(this.x);
+}
+
+void main() {
+  C c = ++.member();
+  print(c);
+}
+''',
+      [
+        error(CompileTimeErrorCode.DOT_SHORTHAND_UNDEFINED_INVOCATION, 89, 6),
+        error(ParserErrorCode.MISSING_ASSIGNABLE_SELECTOR, 96, 1),
+      ],
+    );
+  }
+
   test_requiredParameters_missing() async {
     await assertErrorsInCode(
       r'''

pkg/analyzer/test/src/dart/resolution/dot_shorthand_property_access_test.dart

@@ -2,6 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'package:analyzer/src/dart/error/syntactic_errors.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
@@ -563,6 +564,48 @@ DotShorthandPropertyAccess
 ''');
   }
 
+  test_postfixOperator() async {
+    await assertErrorsInCode(
+      r'''
+class C {
+  static C get member => C(1);
+  int x;
+  C(this.x);
+}
+
+void main() {
+  C c = .member++;
+  print(c);
+}
+''',
+      [
+        error(CompileTimeErrorCode.DOT_SHORTHAND_MISSING_CONTEXT, 88, 7),
+        error(ParserErrorCode.ILLEGAL_ASSIGNMENT_TO_NON_ASSIGNABLE, 95, 2),
+      ],
+    );
+  }
+
+  test_prefixOperator() async {
+    await assertErrorsInCode(
+      r'''
+class C {
+  static C get member => C(1);
+  int x;
+  C(this.x);
+}
+
+void main() {
+  C c = ++.member;
+  print(c);
+}
+''',
+      [
+        error(CompileTimeErrorCode.DOT_SHORTHAND_MISSING_CONTEXT, 90, 7),
+        error(ParserErrorCode.MISSING_ASSIGNABLE_SELECTOR, 91, 6),
+      ],
+    );
+  }
+
   test_tearOff_constructor() async {
     await assertNoErrorsInCode(r'''
 class C1 {