Implement canonical name scheme in kernel.

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 1a1b5ad606f82b05a9988524b00003cb8aecf4b1..8480a899afe07d18536c84007172142baa5146b8 100644
--- a/pkg/kernel/lib/verifier.dart
+++ b/pkg/kernel/lib/verifier.dart
@@ -133,7 +133,17 @@ class VerifyingVisitor extends RecursiveVisitor {
     }
   }
 
+  void checkCanonicalName(CanonicalName name, LinkedNode definition) {

[kustermann, 2017/02/01 13:00:54]

You could also verify that name._children is minimal?

[asgerf, 2017/02/02 12:30:27]

Follow-up on the previous comment:

It is hard to purge unused canonical names while maintaining a nice API,
especially since we have intermediate canonical name nodes that are not bound to
anything, such as <class>::@methods.  It's not very nice that calling
getChild('@methods') makes the tree invalid if there happens to be no methods.

+    if (name == null) {
+      throw '$definition has no canonical name';
+    }
+    if (name.definition != definition) {
+      throw '$definition has name $name, but that is bound to ${name.definition}';

[kustermann, 2017/02/01 13:00:54]

maybe run dartfmt

[asgerf, 2017/02/02 12:30:27]

Done.

+    }
+  }
+
   visitField(Field node) {
+    checkCanonicalName(node.canonicalName, node);
     currentMember = node;
     var oldParent = enterParent(node);
     classTypeParametersAreInScope = !node.isStatic;
@@ -145,6 +155,7 @@ class VerifyingVisitor extends RecursiveVisitor {
   }
 
   visitProcedure(Procedure node) {
+    checkCanonicalName(node.canonicalName, node);
     currentMember = node;
     var oldParent = enterParent(node);
     classTypeParametersAreInScope = !node.isStatic;
@@ -156,6 +167,7 @@ class VerifyingVisitor extends RecursiveVisitor {
   }
 
   visitConstructor(Constructor node) {
+    checkCanonicalName(node.canonicalName, node);
     currentMember = node;
     classTypeParametersAreInScope = true;
     // The constructor member needs special treatment due to parameters being
@@ -173,6 +185,7 @@ class VerifyingVisitor extends RecursiveVisitor {
   }
 
   visitClass(Class node) {
+    checkCanonicalName(node.canonicalName, node);
     currentClass = node;
     declareTypeParameters(node.typeParameters);
     var oldParent = enterParent(node);