Disallow null in spanFromSpannable.

Closes #27938

R=sigmund@google.com

Review URL: https://codereview.chromium.org/2537303004 .

pkg/compiler/lib/src/compiler.dart

@@ -1792,8 +1792,6 @@ class CompilerDiagnosticReporter extends DiagnosticReporter {
   }
 
   SourceSpan spanFromSpannable(Spannable node) {
-    // TODO(johnniwinther): Disallow `node == null` ?
-    if (node == null) return null;
     if (node == CURRENT_ELEMENT_SPANNABLE) {
       node = currentElement;
     } else if (node == NO_LOCATION_SPANNABLE) {

pkg/compiler/lib/src/library_loader.dart

@@ -427,7 +427,8 @@ class _LibraryLoaderTask extends CompilerTask implements LibraryLoaderTask {
       // TODO(johnniwinther): Ensure that currentHandler correctly encloses the
       // loading of a library cluster.
       currentHandler = new LibraryDependencyHandler(this);
-      return createLibrary(currentHandler, null, resolvedUri,
+      return createLibrary(
+              currentHandler, null, resolvedUri, NO_LOCATION_SPANNABLE,
               skipFileWithPartOfTag: skipFileWithPartOfTag)
           .then((LibraryElement library) {
         if (library == null) {
@@ -543,7 +544,7 @@ class _LibraryLoaderTask extends CompilerTask implements LibraryLoaderTask {
 
         // Import dart:core if not already imported.
         if (!importsDartCore && library.canonicalUri != Uris.dart_core) {
-          return createLibrary(handler, null, Uris.dart_core)
+          return createLibrary(handler, null, Uris.dart_core, library)
               .then((LibraryElement coreLibrary) {
             handler.registerDependency(
                 library,
@@ -629,7 +630,7 @@ class _LibraryLoaderTask extends CompilerTask implements LibraryLoaderTask {
       LibraryElement library, LibraryDependencyElementX libraryDependency) {
     Uri base = library.canonicalUri;
     Uri resolvedUri = base.resolveUri(libraryDependency.uri);
-    return createLibrary(handler, library, resolvedUri, node: libraryDependency)
+    return createLibrary(handler, library, resolvedUri, libraryDependency)
         .then((LibraryElement loadedLibrary) {
       if (loadedLibrary == null) return;
       reporter.withCurrentElement(library, () {
@@ -650,15 +651,15 @@ class _LibraryLoaderTask extends CompilerTask implements LibraryLoaderTask {
     return listener.onLibraryScanned(library, handler).then((_) {
       return Future.forEach(library.imports, (ImportElement import) {
         Uri resolvedUri = library.canonicalUri.resolveUri(import.uri);
-        return createLibrary(handler, library, resolvedUri);
+        return createLibrary(handler, library, resolvedUri, library);
       }).then((_) {
         return Future.forEach(library.exports, (ExportElement export) {
           Uri resolvedUri = library.canonicalUri.resolveUri(export.uri);
-          return createLibrary(handler, library, resolvedUri);
+          return createLibrary(handler, library, resolvedUri, library);
         }).then((_) {
           // TODO(johnniwinther): Shouldn't there be an [ImportElement] for the
           // implicit import of dart:core?
-          return createLibrary(handler, library, Uris.dart_core);
+          return createLibrary(handler, library, Uris.dart_core, library);
         }).then((_) => library);
       });
     });
@@ -680,10 +681,10 @@ class _LibraryLoaderTask extends CompilerTask implements LibraryLoaderTask {
    * If a new library is created, the [handler] is notified.
    */
   Future<LibraryElement> createLibrary(LibraryDependencyHandler handler,
-      LibraryElement importingLibrary, Uri resolvedUri,
+      LibraryElement importingLibrary, Uri resolvedUri, Spannable spannable,
-      {Spannable node, bool skipFileWithPartOfTag: false}) {
+      {bool skipFileWithPartOfTag: false}) {
     Uri readableUri =
-        uriTranslator.translate(importingLibrary, resolvedUri, node);
+        uriTranslator.translate(importingLibrary, resolvedUri, spannable);
     LibraryElement library = libraryCanonicalUriMap[resolvedUri];
     if (library != null) {
       return new Future.value(library);
@@ -693,7 +694,7 @@ class _LibraryLoaderTask extends CompilerTask implements LibraryLoaderTask {
         return loadDeserializedLibrary(handler, library);
       }
       return reporter.withCurrentElement(importingLibrary, () {
-        return _readScript(node, readableUri, resolvedUri)
+        return _readScript(spannable, readableUri, resolvedUri)
             .then((Script script) {
           if (script == null) return null;
           LibraryElement element =
@@ -721,7 +722,7 @@ class _LibraryLoaderTask extends CompilerTask implements LibraryLoaderTask {
               DiagnosticMessage info = reporter.withCurrentElement(
                   importingLibrary,
                   () => reporter.createMessage(
-                      node, MessageKind.IMPORT_PART_OF_HERE));
+                      spannable, MessageKind.IMPORT_PART_OF_HERE));
               reporter.reportError(error, [info]);
             }
           }

pkg/compiler/lib/src/resolution/class_hierarchy.dart

@@ -482,12 +482,12 @@ class ClassResolverVisitor extends TypeDefinitionVisitor {
       if (interfaceType != null) {
         if (interfaceType.isMalformed) {
           reporter.reportErrorMessage(
-              superclass,
+              link.head,
               MessageKind.CANNOT_IMPLEMENT_MALFORMED,
               {'className': element.name, 'malformedType': interfaceType});
         } else if (interfaceType.isEnumType) {
           reporter.reportErrorMessage(
-              superclass,
+              link.head,
               MessageKind.CANNOT_IMPLEMENT_ENUM,
               {'className': element.name, 'enumType': interfaceType});
         } else if (!interfaceType.isInterfaceType) {

pkg/compiler/lib/src/resolution/constructors.dart

@@ -345,7 +345,7 @@ class InitializerResolver {
         if (!field.isMalformed) {
           registry.registerStaticUse(new StaticUse.fieldInit(field));
         }
-        checkForDuplicateInitializers(field, element.initializer);
+        checkForDuplicateInitializers(field, parameterNode);
         visitor.defineLocalVariable(parameterNode, initializingFormal);
         visitor.addToScope(initializingFormal);
         if (isConst) {

pkg/compiler/lib/src/resolved_uri_translator.dart

@@ -35,8 +35,7 @@ abstract class ResolvedUriTranslator {
   /// responsible for reporting errors.
   ///
   /// See [LibraryLoader] for terminology on URIs.
-  Uri translate(LibraryElement importingLibrary, Uri uri,
+  Uri translate(LibraryElement importingLibrary, Uri uri, Spannable spannable);
-      [Spannable spannable]);
 }
 
 /// A translator that forwards all methods to an internal
@@ -59,7 +58,7 @@ class ForwardingResolvedUriTranslator implements ResolvedUriTranslator {
 
   @override
   Uri translate(LibraryElement importingLibrary, Uri resolvedUri,
-          [Spannable spannable]) =>
+          Spannable spannable) =>
       resolvedUriTranslator.translate(importingLibrary, resolvedUri, spannable);
 
   @override
@@ -86,8 +85,7 @@ class _ResolvedUriTranslator implements ResolvedUriTranslator {
   Map<String, Uri> get sdkLibraries => _sdkLibraries;
 
   @override
-  Uri translate(LibraryElement importingLibrary, Uri uri,
+  Uri translate(LibraryElement importingLibrary, Uri uri, Spannable spannable) {
-      [Spannable spannable]) {
     if (uri.scheme == 'dart') {
       return translateDartUri(importingLibrary, uri, spannable);
     }

tests/compiler/dart2js/mock_compiler.dart

@@ -290,7 +290,7 @@ class MockResolvedUriTranslator implements ResolvedUriTranslator {
   static final _emptySet = new Set();
 
   Uri translate(LibraryElement importingLibrary, Uri resolvedUri,
-          [Spannable spannable]) =>
+          Spannable spannable) =>
       resolvedUri;
   Set<Uri> get disallowedLibraryUris => _emptySet;
   bool get mockableLibraryUsed => false;