Revert "Add typedef AST node boilerplate."

pkg/kernel/lib/verifier.dart

Index: pkg/kernel/lib/verifier.dart
diff --git a/pkg/kernel/lib/verifier.dart b/pkg/kernel/lib/verifier.dart
index 18b93c320b958c61207f85c805d3a741a2582b03..c518a6566f3f562eeb19d198f6e568c89256dc47 100644
--- a/pkg/kernel/lib/verifier.dart
+++ b/pkg/kernel/lib/verifier.dart
@@ -38,17 +38,13 @@ class VerificationError {
   }
 }
 
-enum TypedefState { Done, BeingChecked }
-
 /// Checks that a kernel program is well-formed.
 ///
 /// This does not include any kind of type checking.
 class VerifyingVisitor extends RecursiveVisitor {
   final Set<Class> classes = new Set<Class>();
-  final Set<Typedef> typedefs = new Set<Typedef>();
-  Set<TypeParameter> typeParametersInScope = new Set<TypeParameter>();
+  final Set<TypeParameter> typeParameters = new Set<TypeParameter>();
   final List<VariableDeclaration> variableStack = <VariableDeclaration>[];
-  final Map<Typedef, TypedefState> typedefState = <Typedef, TypedefState>{};
   bool classTypeParametersAreInScope = false;
 
   /// If true, relax certain checks for *outline* mode. For example, don't
@@ -71,8 +67,7 @@ class VerifyingVisitor extends RecursiveVisitor {
     visitChildren(node);
   }
 
-  problem(TreeNode node, String details, {TreeNode context}) {
-    context ??= this.context;
+  problem(TreeNode node, String details) {
     throw new VerificationError(context, node, details);
   }
 
@@ -80,8 +75,7 @@ class VerifyingVisitor extends RecursiveVisitor {
     if (!identical(node.parent, currentParent)) {
       problem(
           node,
-          "Incorrect parent pointer on ${node.runtimeType}:"
-          " expected '${node.parent.runtimeType}',"
+          "Incorrect parent pointer: expected '${node.parent.runtimeType}',"
           " but found: '${currentParent.runtimeType}'.");
     }
     var oldParent = currentParent;
@@ -141,14 +135,14 @@ class VerifyingVisitor extends RecursiveVisitor {
   void declareTypeParameters(List<TypeParameter> parameters) {
     for (int i = 0; i < parameters.length; ++i) {
       var parameter = parameters[i];
-      if (!typeParametersInScope.add(parameter)) {
+      if (!typeParameters.add(parameter)) {
         problem(parameter, "Type parameter '$parameter' redeclared.");
       }
     }
   }
 
   void undeclareTypeParameters(List<TypeParameter> parameters) {
-    typeParametersInScope.removeAll(parameters);
+    typeParameters.removeAll(parameters);
   }
 
   void checkVariableInScope(VariableDeclaration variable, TreeNode where) {
@@ -165,11 +159,6 @@ class VerifyingVisitor extends RecursiveVisitor {
             problem(class_, "Class '$class_' declared more than once.");
           }
         }
-        for (var typedef_ in library.typedefs) {
-          if (!typedefs.add(typedef_)) {
-            problem(typedef_, "Typedef '$typedef_' declared more than once.");
-          }
-        }
         library.members.forEach(declareMember);
         for (var class_ in library.classes) {
           class_.members.forEach(declareMember);
@@ -187,32 +176,6 @@ class VerifyingVisitor extends RecursiveVisitor {
     }
   }
 
-  void checkTypedef(Typedef node) {
-    var state = typedefState[node];
-    if (state == TypedefState.Done) return;
-    if (state == TypedefState.BeingChecked) {
-      problem(node, "The typedef '$node' refers to itself", context: node);
-    }
-    assert(state == null);
-    typedefState[node] = TypedefState.BeingChecked;
-    var savedTypeParameters = typeParametersInScope;
-    typeParametersInScope = node.typeParameters.toSet();
-    var savedParent = currentParent;
-    currentParent = node;
-    // Visit children without checking the parent pointer on the typedef itself
-    // since this can be called from a context other than its true parent.
-    node.visitChildren(this);
-    currentParent = savedParent;
-    typeParametersInScope = savedTypeParameters;
-    typedefState[node] = TypedefState.Done;
-  }
-
-  visitTypedef(Typedef node) {
-    checkTypedef(node);
-    // Enter and exit the node to check the parent pointer on the typedef node.
-    exitParent(enterParent(node));
-  }
-
   visitField(Field node) {
     currentMember = node;
     var oldParent = enterParent(node);
@@ -221,7 +184,6 @@ class VerifyingVisitor extends RecursiveVisitor {
     classTypeParametersAreInScope = false;
     visitList(node.annotations, this);
     exitParent(oldParent);
-    node.type.accept(this);
     currentMember = null;
   }
 
@@ -530,17 +492,9 @@ class VerifyingVisitor extends RecursiveVisitor {
   }
 
   @override
-  visitTypedefReference(Typedef node) {
-    if (!typedefs.contains(node)) {
-      problem(
-          node, "Dangling reference to '$node', parent is: '${node.parent}'");
-    }
-  }
-
-  @override
   visitTypeParameterType(TypeParameterType node) {
     var parameter = node.parameter;
-    if (!typeParametersInScope.contains(parameter)) {
+    if (!typeParameters.contains(parameter)) {
       problem(
           currentParent,
           "Type parameter '$parameter' referenced out of"
@@ -565,19 +519,6 @@ class VerifyingVisitor extends RecursiveVisitor {
           " ${node.classNode.typeParameters.length} parameters.");
     }
   }
-
-  @override
-  visitTypedefType(TypedefType node) {
-    checkTypedef(node.typedefNode);
-    node.visitChildren(this);
-    if (node.typeArguments.length != node.typedefNode.typeParameters.length) {
-      problem(
-          currentParent,
-          "The typedef type $node provides ${node.typeArguments.length}"
-          " type arguments but the typedef declares"
-          " ${node.typedefNode.typeParameters.length} parameters.");
-    }
-  }
 }
 
 class CheckParentPointers extends Visitor {