Unresolved super-send is not a compile-time error.

dart/frog/leg/ssa/builder.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 class Interceptors {
   Compiler compiler;
   Interceptors(Compiler this.compiler);
 
   SourceString mapOperatorToMethodName(Operator op) {
     String name = op.source.stringValue;
@@ skipping 1759 matching lines @@
         native.handleSsaNative(this, node);
         break;
       default:
         throw "Unknown foreign: ${node.selector}";
     }
   }
 
   visitSuperSend(Send node) {
     Selector selector = elements.getSelector(node);
     Element element = elements[node];
+    if (element === null) {
+      // Example: co19/Language/10_Expressions/25_Unary_Expressions_A06_t01
+      compiler.unimplemented('unresolved super-send', node: node);
+    }
     if (element.kind.category != ElementCategory.FUNCTION) {
       // Example:
       // co19/Language/10_Expressions/14_Method_Invocation/3_Super_Invocation_A03_t04
       compiler.unimplemented('super-send to non-function', node: node);
     }
     HStatic target = new HStatic(element);
     HInstruction context = localsHandler.readThis();
     add(target);
     var inputs = <HInstruction>[target, context];
     addStaticSendArgumentsToList(node, element, inputs);
@@ skipping 21 matching lines @@
         target = new HInvokeStatic(Selector.GETTER, inputs);
         add(target);
         inputs = <HInstruction>[target];
       }
       addDynamicSendArgumentsToList(node, inputs);
       push(new HInvokeClosure(selector, inputs));
     }
   }
 
   visitSend(Send node) {
-    if (node.selector is Operator && methodInterceptionEnabled) {
+    if (node.isSuperCall) {
+      if (node.isPropertyAccess) {
+        compiler.unimplemented('super property read', node: node);
+      }
+      visitSuperSend(node);
+    } else if (node.selector is Operator && methodInterceptionEnabled) {
       visitOperatorSend(node);
     } else if (node.isPropertyAccess) {
       generateGetter(node, elements[node]);
     } else if (Elements.isClosureSend(node, elements)) {
       visitClosureSend(node);
-    } else if (node.isSuperCall) {
-      visitSuperSend(node);
     } else {
       Element element = elements[node];
       if (element === null) {
         // Example: f() with 'f' unbound.
         // This can only happen inside an instance method.
         visitDynamicSend(node);
       } else if (element.kind == ElementKind.CLASS) {
         compiler.internalError("Cannot generate code for send", node: node);
       } else if (element.isInstanceMember()) {
         // Example: f() with 'f' bound to instance method.
         visitDynamicSend(node);
       } else if (element.kind === ElementKind.FOREIGN) {
         visitForeignSend(node);
       } else if (!element.isInstanceMember()) {
         // Example: A.f() or f() with 'f' bound to a static function.
         // Also includes new A() or new A.named() which is treated like a
         // static call to a factory.
         visitStaticSend(node);
       } else {
         compiler.internalError("Cannot generate code for send", node: node);
       }
     }
   }
 
   visitNewExpression(NewExpression node) => visitSend(node.send);
 
   visitSendSet(SendSet node) {
     Operator op = node.assignmentOperator;
-    if (node.isIndex) {
+    if (node.isSuperCall) {
+      compiler.unimplemented('super property store', node: node);
+    } else if (node.isIndex) {
       if (!methodInterceptionEnabled) {
         assert(op.source.stringValue === '=');
         visitDynamicSend(node);
       } else {
         HStatic target = new HStatic(
             interceptors.getIndexAssignmentInterceptor());
         add(target);
         visit(node.receiver);
         HInstruction receiver = pop();
         visit(node.argumentsNode);
@@ skipping 616 matching lines @@
     buildBody() {
       // TODO(lrn): Make sure to take continue into account.
       visit(body);
       if (isAborted()) {
         compiler.reportWarning(body, "aborting loop body");
       }
     }
     handleIf(buildBody, null);
   }
 }