[cfe] Complete basic implementation of round-trip text serialization

The future non-basic version is to include the following:

  * adding missing annotations on nodes
  * adding URIs and file offsets to the nodes
  * adding nullability markers to types
  * stylistic changes
  * optimizations
  * better surface syntax
  * better error messages

Change-Id: If2fc51e4932d9043dd1719b766bd23ff4e0fc1ad
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/154001
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Dmitry Stefantsov <dmitryas@google.com>

Author: Dmitry Stefantsov

pkg/front_end/test/spell_checking_list_code.txt

@@ -1144,6 +1144,7 @@ tuple3
 tuple4
 tuple5
 tuple6
+tuple7
 type1
 type2
 typeref

pkg/front_end/test/spell_checking_list_common.txt

@@ -2643,6 +2643,7 @@ setting
 settings
 settled
 setup
+seventh
 several
 severity
 shadow

pkg/kernel/lib/ast.dart

@@ -1471,7 +1471,7 @@ class Extension extends NamedNode implements FileUriNode {
       {this.name,
       List<TypeParameter> typeParameters,
       this.onType,
-      List<Reference> members,
+      List<ExtensionMemberDescriptor> members,
       this.fileUri,
       Reference reference})
       : this.typeParameters = typeParameters ?? <TypeParameter>[],

pkg/kernel/lib/text/serializer_combinators.dart

@@ -517,6 +517,62 @@ class Tuple6<T1, T2, T3, T4, T5, T6> {
       this.first, this.second, this.third, this.fourth, this.fifth, this.sixth);
 }
 
+class Tuple7Serializer<T1, T2, T3, T4, T5, T6, T7>
+    extends TextSerializer<Tuple7<T1, T2, T3, T4, T5, T6, T7>> {
+  final TextSerializer<T1> first;
+  final TextSerializer<T2> second;
+  final TextSerializer<T3> third;
+  final TextSerializer<T4> fourth;
+  final TextSerializer<T5> fifth;
+  final TextSerializer<T6> sixth;
+  final TextSerializer<T7> seventh;
+
+  const Tuple7Serializer(this.first, this.second, this.third, this.fourth,
+      this.fifth, this.sixth, this.seventh);
+
+  Tuple7<T1, T2, T3, T4, T5, T6, T7> readFrom(
+      Iterator<Object> stream, DeserializationState state) {
+    return new Tuple7(
+        first.readFrom(stream, state),
+        second.readFrom(stream, state),
+        third.readFrom(stream, state),
+        fourth.readFrom(stream, state),
+        fifth.readFrom(stream, state),
+        sixth.readFrom(stream, state),
+        seventh.readFrom(stream, state));
+  }
+
+  void writeTo(StringBuffer buffer, Tuple7<T1, T2, T3, T4, T5, T6, T7> object,
+      SerializationState state) {
+    first.writeTo(buffer, object.first, state);
+    if (!second.isEmpty) buffer.write(' ');
+    second.writeTo(buffer, object.second, state);
+    if (!third.isEmpty) buffer.write(' ');
+    third.writeTo(buffer, object.third, state);
+    if (!fourth.isEmpty) buffer.write(' ');
+    fourth.writeTo(buffer, object.fourth, state);
+    if (!fifth.isEmpty) buffer.write(' ');
+    fifth.writeTo(buffer, object.fifth, state);
+    if (!sixth.isEmpty) buffer.write(' ');
+    sixth.writeTo(buffer, object.sixth, state);
+    if (!seventh.isEmpty) buffer.write(' ');
+    seventh.writeTo(buffer, object.seventh, state);
+  }
+}
+
+class Tuple7<T1, T2, T3, T4, T5, T6, T7> {
+  final T1 first;
+  final T2 second;
+  final T3 third;
+  final T4 fourth;
+  final T5 fifth;
+  final T6 sixth;
+  final T7 seventh;
+
+  const Tuple7(this.first, this.second, this.third, this.fourth, this.fifth,
+      this.sixth, this.seventh);
+}
+
 // A serializer/deserializer for lists.
 class ListSerializer<T> extends TextSerializer<List<T>> {
   final TextSerializer<T> elements;

pkg/kernel/lib/text/text_serialization_verifier.dart

@@ -29,9 +29,9 @@ abstract class RoundTripStatus implements Comparable<RoundTripStatus> {
   RoundTripStatus(this.node, {TreeNode context})
       : context = node is TreeNode && node.location != null ? node : context;
 
-  Uri get uri => context.location.file;
+  Uri get uri => context?.location?.file;
 
-  int get offset => context.fileOffset;
+  int get offset => context?.fileOffset;
 
   bool get isSuccess;
 
@@ -324,15 +324,7 @@ class VerificationState {
 
   static bool isSupported(Node node) => !isNotSupported(node);
 
-  static bool isNotSupported(Node node) =>
-      node is Component ||
-      node is Extension ||
-      node is Library ||
-      node is LibraryPart ||
-      node is MapEntry ||
-      node is Name && node.isPrivate ||
-      node is RedirectingFactoryConstructor ||
-      node is Typedef;
+  static bool isNotSupported(Node node) => false;
 }
 
 class TextSerializationVerifier extends RecursiveVisitor<void> {
@@ -483,6 +475,16 @@ class TextSerializationVerifier extends RecursiveVisitor<void> {
       makeRoundTrip<Supertype>(node, supertypeSerializer);
     } else if (node is Class) {
       makeRoundTrip<Class>(node, classSerializer);
+    } else if (node is Extension) {
+      makeRoundTrip<Extension>(node, extensionSerializer);
+    } else if (node is Typedef) {
+      makeRoundTrip<Typedef>(node, typedefSerializer);
+    } else if (node is LibraryPart) {
+      makeRoundTrip<LibraryPart>(node, libraryPartSerializer);
+    } else if (node is Library) {
+      makeRoundTrip<Library>(node, librarySerializer);
+    } else if (node is Component) {
+      makeRoundTrip<Component>(node, componentSerializer);
     } else {
       throw new StateError(
           "Don't know how to make a round trip for a supported node "