[parser] Dot shorthands: Remove synthetic token in parser.

Context:
A while back, I inserted a synthetic token in the parser to allow us to parse without crashing the analyzer while I worked on the CFE. Now that both implementations are up and working, we can remove this synthetic token and allow the parser to parse as if we had enabled dot shorthands by default, and produce an error if the experiment isn't enabled.

This change allows a bunch of different language tests to start passing since they were blocked on the weird synthetic token messing up the parsing stream.

Bug: #59758
Change-Id: I792e3b917a76241b04ee708de06f670bbde64036
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/423563
Reviewed-by: Chloe Stefantsova <[email protected]>
Commit-Queue: Kallen Tu <[email protected]>

Author: kallentu

pkg/_fe_analyzer_shared/lib/src/parser/parser_impl.dart

@@ -5844,14 +5844,7 @@ class Parser {
     assert(precedence <= SELECTOR_PRECEDENCE);
 
     bool isDotShorthand = _isDotShorthand(token.next!);
-    if (isDotShorthand) {
-      // TODO(kallentu): Once the analyzer implementation is done, we can avoid
-      // adding a synthetic identifier completely, but currently, the parser
-      // will crash without one.
-      //
-      // Insert a synthetic identifier to satisfy listeners.
-      token = rewriter.insertSyntheticIdentifier(token);
-    } else {
+    if (!isDotShorthand) {
       token =
           parseUnaryExpression(token, allowCascades, constantPatternContext);
     }

pkg/front_end/lib/src/kernel/body_builder.dart

@@ -10033,7 +10033,6 @@ class BodyBuilder extends StackListenerImpl
               .withArguments(ExperimentalFlag.dotShorthands.name),
           token.offset,
           token.length);
-      return;
     }
 
     assert(checkState(token, [
@@ -10055,30 +10054,23 @@ class BodyBuilder extends StackListenerImpl
               .withArguments(ExperimentalFlag.dotShorthands.name),
           token.offset,
           token.length);
-
-      // Recovery, avoid crashing with an extra selector.
-      pop();
-      push(new ParserErrorGenerator(this, token, cfe.messageSyntheticToken));
-      return;
     }
 
     assert(checkState(token, [ValueKinds.Selector]));
     Selector selector = pop() as Selector;
-    if (libraryFeatures.dotShorthands.isEnabled) {
-      if (selector is InvocationSelector) {
-        // e.g. `.parse(2)`
-        push(forest.createDotShorthandInvocation(
-            offsetForToken(token), selector.name, selector.arguments,
-            nameOffset: offsetForToken(token.next),
-            isConst: constantContext == ConstantContext.inferred));
-      } else if (selector is PropertySelector) {
-        // e.g. `.zero`
-        push(forest.createDotShorthandPropertyGet(
-          offsetForToken(token),
-          selector.name,
+    if (selector is InvocationSelector) {
+      // e.g. `.parse(2)`
+      push(forest.createDotShorthandInvocation(
+          offsetForToken(token), selector.name, selector.arguments,
           nameOffset: offsetForToken(token.next),
-        ));
-      }
+          isConst: constantContext == ConstantContext.inferred));
+    } else if (selector is PropertySelector) {
+      // e.g. `.zero`
+      push(forest.createDotShorthandPropertyGet(
+        offsetForToken(token),
+        selector.name,
+        nameOffset: offsetForToken(token.next),
+      ));
     }
   }
 

pkg/front_end/parser_testcases/dot_shorthands/syntax.dart.intertwined.expect

@@ -104,7 +104,6 @@ parseUnit(enum)
                       listener: beginVariableInitializer(=)
                       parseExpression(=)
                         parsePrecedenceExpression(=, 1, true, ConstantPatternContext.none)
-                          rewriter()
                           parsePrimary(., expressionContinuation, ConstantPatternContext.none)
                             parseSendOrFunctionLiteral(., expressionContinuation, ConstantPatternContext.none)
                               parseSend(., expressionContinuation, ConstantPatternContext.none)

pkg/front_end/parser_testcases/dot_shorthands/syntax.dart.parser.expect

@@ -1,15 +1,13 @@
-NOTICE: Stream was rewritten by parser!
-
 enum Color { red, blue, green }
 
 void main() {
-Color c = *synthetic*.red;
+Color c = .red;
 }
 
 
 enum[KeywordToken] Color[StringToken] {[BeginToken] red[StringToken],[SimpleToken] blue[StringToken],[SimpleToken] green[StringToken] }[SimpleToken]
 
 void[KeywordToken] main[StringToken]([BeginToken])[SimpleToken] {[BeginToken]
-Color[StringToken] c[StringToken] =[SimpleToken] [SyntheticStringToken].[SimpleToken]red[StringToken];[SimpleToken]
+Color[StringToken] c[StringToken] =[SimpleToken] .[SimpleToken]red[StringToken];[SimpleToken]
 }[SimpleToken]
 [SimpleToken]

tests/language/dot_shorthands/simple/simple_identifier_if_null_test.dart

@@ -43,17 +43,17 @@ void main() {
   noContextLHSContextColor(Color.red);
 
   // Class
-  Expect.equals(integerTest(null), Integer.one);
-  Expect.equals(integerTest(Integer.two), Integer.two);
+  Expect.equals(integerTest(null).integer, 1);
+  Expect.equals(integerTest(Integer.two).integer, 2);
 
   noContextLHSContextInteger(null);
   noContextLHSContextInteger(Integer.one);
 
   Integer possiblyNullableInteger = .nullable ?? Integer.one;
 
   // Extension type
-  Expect.equals(integerExtTest(null), IntegerExt.one);
-  Expect.equals(integerExtTest(IntegerExt.two), IntegerExt.two);
+  Expect.equals(integerExtTest(null).integer, 1);
+  Expect.equals(integerExtTest(IntegerExt.two).integer, 2);
 
   noContextLHSContextIntegerExt(null);
   noContextLHSContextIntegerExt(IntegerExt.one);
@@ -62,8 +62,8 @@ void main() {
   IntegerExt possiblyNullableIntegerExt2 = .one ?? IntegerExt.one;
 
   // Mixin
-  Expect.equals(integerMixinTest(null), IntegerMixin.mixinOne);
-  Expect.equals(integerMixinTest(IntegerMixin.mixinTwo), IntegerMixin.mixinTwo);
+  Expect.equals(integerMixinTest(null).integer, 1);
+  Expect.equals(integerMixinTest(IntegerMixin.mixinTwo).integer, 2);
 
   noContextLHSContextIntegerMixin(null);
   noContextLHSContextIntegerMixin(IntegerMixin.mixinOne);

tests/language/explicit_type_instantiation_parsing_test.dart

@@ -250,6 +250,8 @@ void main() {
   //  ^
   // [analyzer] SYNTACTIC_ERROR.EXPERIMENT_NOT_ENABLED
   // [cfe] This requires the experimental 'dot-shorthands' language feature to be enabled.
+  //   ^
+  // [cfe] The static getter or field 'instance' isn't defined for the type 'dynamic'.
 
   X<2>.any;
   // ^
@@ -258,6 +260,8 @@ void main() {
   //  ^
   // [analyzer] SYNTACTIC_ERROR.EXPERIMENT_NOT_ENABLED
   // [cfe] This requires the experimental 'dot-shorthands' language feature to be enabled.
+  //   ^
+  // [cfe] The static getter or field 'any' isn't defined for the type 'dynamic'.
 
   // This would be invalid even if `X` had an `any` member. See next.
   X<X>.any; // Invalid, Class does not have any static `any` member.