DeCo. Support for primary constructor in enums.

Bug: #61701
Change-Id: I1cccda0cc688087fe8f9b72d185a7a07c5f134ce
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/459383
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>

Author: scheglov

pkg/analyzer/lib/src/summary2/element_builder.dart

@@ -1324,7 +1324,7 @@ class FragmentBuilder extends ThrowingAstVisitor<void> {
       );
 
       if (useDeclaringConstructorsAst) {
-        node.namePart.typeParameters?.accept(this);
+        node.namePart.accept(this);
         node.body.members.accept(this);
       } else {
         node.typeParameters?.accept(this);
@@ -1828,7 +1828,8 @@ class FragmentBuilder extends ThrowingAstVisitor<void> {
     }
 
     var fragment = ConstructorFragmentImpl(name: fragmentName);
-    fragment.isConst = node.constKeyword != null;
+    fragment.isConst =
+        node.constKeyword != null || node.parent is EnumDeclarationImpl;
     fragment.typeName = node.typeName.lexeme;
     _linker.elementNodes[fragment] = node;
 

pkg/analyzer/lib/src/summary2/reference_resolver.dart

@@ -173,7 +173,7 @@ class ReferenceResolver extends ThrowingAstVisitor<void> {
 
     node.metadata.accept(this);
     if (useDeclaringConstructorsAst) {
-      node.namePart.typeParameters?.accept(this);
+      node.namePart.accept(this);
     } else {
       node.typeParameters?.accept(this);
     }