[kernel] Add 'leakingDebugToString' to nodes

This serves two purposes:
1) It can aid in debugging to better know which object you have.
2) It paves the way for a future re-design of toString so toString never
   leaks.

Change-Id: Ice32209b19b961b7e92de829d8bee0ddd8bd6e93
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/122140
Commit-Queue: Jens Johansen <jensj@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>

Author: jensjoha

pkg/compiler/lib/src/ir/closure.dart

@@ -3,6 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:kernel/ast.dart' as ir;
+import 'package:kernel/text/ast_to_text.dart' as ir show debugNodeToString;
 
 /// Collection of scope data collected for a single member.
 class ClosureScopeModel {
@@ -414,4 +415,7 @@ class TypeVariableTypeWithContext implements ir.Node {
   String toString() =>
       'TypeVariableTypeWithContext(type=$type,context=$context,'
       'kind=$kind,typeDeclaration=$typeDeclaration)';
+
+  @override
+  String leakingDebugToString() => ir.debugNodeToString(this);
 }

pkg/kernel/lib/ast.dart

@@ -97,6 +97,12 @@ abstract class Node {
   /// (possibly synthesized) name, whereas other AST nodes return the complete
   /// textual representation of their subtree.
   String toString() => debugNodeToString(this);
+
+  /// Returns the textual representation of this node for use in debugging.
+  ///
+  /// Note that this adds some nodes to a static map to ensure consistent
+  /// naming, but that it thus also leaks memory.
+  String leakingDebugToString() => debugNodeToString(this);
 }
 
 /// A mutable AST node with a parent pointer.
@@ -5301,6 +5307,12 @@ abstract class Name implements Node {
   visitChildren(Visitor v) {
     // DESIGN TODO: Should we visit the library as a library reference?
   }
+
+  /// Returns the textual representation of this node for use in debugging.
+  ///
+  /// Note that this adds some nodes to a static map to ensure consistent
+  /// naming, but that it thus also leaks memory.
+  String leakingDebugToString() => debugNodeToString(this);
 }
 
 class _PrivateName extends Name {