Added variance support in listeners to ast.

Pass variance data to field in TypeParameter through the listeners.
ast_to_text will print variances for classes and mixins if specified.

Avoids serialization/deserialization (impl in future CL).

Change-Id: I298537604823710f0d30001f4cb5f1e81530959f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/118464
Commit-Queue: Kallen Tu <[email protected]>
Reviewed-by: Dmitry Stefantsov <[email protected]>

Author: kallentu

pkg/analyzer/lib/src/fasta/ast_builder.dart

@@ -2090,7 +2090,8 @@ class AstBuilder extends StackListener {
   }
 
   @override
-  void endTypeVariable(Token token, int index, Token extendsOrSuper) {
+  void endTypeVariable(
+      Token token, int index, Token extendsOrSuper, Token variance) {
     debugEvent("TypeVariable");
     assert(extendsOrSuper == null ||
         optional('extends', extendsOrSuper) ||

pkg/analyzer/test/generated/parser_fasta_listener.dart

@@ -1152,9 +1152,10 @@ class ForwardingTestListener extends ForwardingListener {
   }
 
   @override
-  void endTypeVariable(Token token, int index, Token extendsOrSuper) {
+  void endTypeVariable(
+      Token token, int index, Token extendsOrSuper, Token variance) {
     end('TypeVariable');
-    super.endTypeVariable(token, index, extendsOrSuper);
+    super.endTypeVariable(token, index, extendsOrSuper, variance);
   }
 
   @override

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

@@ -4767,14 +4767,18 @@ class BodyBuilder extends ScopeListener<JumpTarget>
   }
 
   @override
-  void endTypeVariable(Token token, int index, Token extendsOrSuper) {
+  void endTypeVariable(
+      Token token, int index, Token extendsOrSuper, Token variance) {
     debugEvent("TypeVariable");
     UnresolvedType bound = pop();
     // Peek to leave type parameters on top of stack.
     List<TypeVariableBuilder> typeVariables = peek();
 
     TypeVariableBuilder variable = typeVariables[index];
     variable.bound = bound?.builder;
+    if (variance != null) {
+      variable.variance = Variance.fromString(variance.lexeme);
+    }
   }
 
   @override

pkg/front_end/lib/src/fasta/parser/forwarding_listener.dart

@@ -993,8 +993,9 @@ class ForwardingListener implements Listener {
   }
 
   @override
-  void endTypeVariable(Token token, int index, Token extendsOrSuper) {
-    listener?.endTypeVariable(token, index, extendsOrSuper);
+  void endTypeVariable(
+      Token token, int index, Token extendsOrSuper, Token variance) {
+    listener?.endTypeVariable(token, index, extendsOrSuper, variance);
   }
 
   @override

pkg/front_end/lib/src/fasta/parser/listener.dart

@@ -1220,7 +1220,8 @@ class Listener implements UnescapeErrorListener {
   /// - Type bound
   ///
   /// See [beginTypeVariable] for additional substructures.
-  void endTypeVariable(Token token, int index, Token extendsOrSuper) {
+  void endTypeVariable(
+      Token token, int index, Token extendsOrSuper, Token variance) {
     logEvent("TypeVariable");
   }
 

pkg/front_end/lib/src/fasta/parser/type_info_impl.dart

@@ -763,7 +763,7 @@ class SimpleTypeArgument1 extends TypeParamOrArgInfo {
     listener.beginTypeVariable(token);
     listener.handleTypeVariablesDefined(token, 1);
     listener.handleNoType(token);
-    listener.endTypeVariable(endGroup, 0, null);
+    listener.endTypeVariable(endGroup, 0, null, null);
     listener.endTypeVariables(beginGroup, endGroup);
     return endGroup;
   }
@@ -1075,7 +1075,7 @@ class ComplexTypeParamOrArgInfo extends TypeParamOrArgInfo {
       // Type variables are "completed" in reverse order, so capture the last
       // consumed token from the first "completed" type variable.
       token ??= token2;
-      listener.endTypeVariable(next2, --count, extendsOrSuper);
+      listener.endTypeVariable(next2, --count, extendsOrSuper, variance);
 
       typeStarts = typeStarts.tail;
       superTypeInfos = superTypeInfos.tail;

pkg/front_end/lib/src/fasta/source/diet_listener.dart

@@ -544,7 +544,8 @@ class DietListener extends StackListener {
   }
 
   @override
-  void endTypeVariable(Token token, int index, Token extendsOrSuper) {
+  void endTypeVariable(
+      Token token, int index, Token extendsOrSuper, Token variance) {
     debugEvent("endTypeVariable");
   }
 

pkg/front_end/lib/src/fasta/source/outline_builder.dart

@@ -4,7 +4,7 @@
 
 library fasta.outline_builder;
 
-import 'package:kernel/ast.dart' show ProcedureKind;
+import 'package:kernel/ast.dart' show ProcedureKind, Variance;
 
 import '../builder/builder.dart';
 
@@ -1574,13 +1574,17 @@ class OutlineBuilder extends StackListener {
   }
 
   @override
-  void endTypeVariable(Token token, int index, Token extendsOrSuper) {
+  void endTypeVariable(
+      Token token, int index, Token extendsOrSuper, Token variance) {
     debugEvent("endTypeVariable");
     TypeBuilder bound = nullIfParserRecovery(pop());
     // Peek to leave type parameters on top of stack.
     List<TypeVariableBuilder> typeParameters = peek();
     if (typeParameters != null) {
       typeParameters[index].bound = bound;
+      if (variance != null) {
+        typeParameters[index].variance = Variance.fromString(variance.lexeme);
+      }
     }
   }
 

pkg/front_end/lib/src/fasta/source/type_promotion_look_ahead_listener.dart

@@ -1316,7 +1316,8 @@ class TypePromotionLookAheadListener extends Listener {
   }
 
   @override
-  void endTypeVariable(Token token, int index, Token extendsOrSuper) {
+  void endTypeVariable(
+      Token token, int index, Token extendsOrSuper, Token variance) {
     debugEvent("TypeVariable", token);
     state.pop(); // Name.
   }
@@ -1326,6 +1327,11 @@ class TypePromotionLookAheadListener extends Listener {
     debugEvent("TypeVariables", beginToken);
   }
 
+  @override
+  void handleVarianceModifier(Token variance) {
+    debugEvent("VarianceModifier", variance);
+  }
+
   @override
   void handleNoTypeVariables(Token token) {
     debugEvent("NoTypeVariables", token);