Suppress follow-on errors when a file is imported with either a prefix or a show clause

pkg/analyzer/lib/src/dart/element/builder.dart

Index: pkg/analyzer/lib/src/dart/element/builder.dart
diff --git a/pkg/analyzer/lib/src/dart/element/builder.dart b/pkg/analyzer/lib/src/dart/element/builder.dart
index 6eaaedb6910bc133bddad43cea1e41ba51b3b927..7296d5b046568a995ad0a626d4eed20a94f1e436 100644
--- a/pkg/analyzer/lib/src/dart/element/builder.dart
+++ b/pkg/analyzer/lib/src/dart/element/builder.dart
@@ -213,53 +213,52 @@ class DirectiveElementBuilder extends SimpleAstVisitor<Object> {
     node.element = null;
     Source importedSource = node.source;
     int importedTime = sourceModificationTimeMap[importedSource] ?? -1;
-    if (importedTime != -1) {
-      // The imported source will be null if the URI in the import
-      // directive was invalid.
-      LibraryElement importedLibrary = importLibraryMap[importedSource];
-      if (importedLibrary != null) {
-        if (importedLibrary.isDartCore) {
-          explicitlyImportsCore = true;
+    // The imported source will be null if the URI in the import

[Brian Wilkerson, 2016/08/08 20:50:38]

I moved the test for a missing source to line 249 (new file) so that we will now
create elements even for missing files. One side effect is that we will also
create PrefixElement's for such an import, so we can now recognize more uses of
prefixes.

+    // directive was invalid.
+    LibraryElement importedLibrary = importLibraryMap[importedSource];
+    if (importedLibrary != null) {
+      if (importedLibrary.isDartCore) {
+        explicitlyImportsCore = true;
+      }
+      ImportElementImpl importElement = new ImportElementImpl(node.offset);
+      importElement.metadata = _getElementAnnotations(node.metadata);
+      StringLiteral uriLiteral = node.uri;
+      if (uriLiteral != null) {
+        importElement.uriOffset = uriLiteral.offset;
+        importElement.uriEnd = uriLiteral.end;
+      }
+      importElement.uri = node.uriContent;
+      importElement.deferred = node.deferredKeyword != null;
+      importElement.combinators = _buildCombinators(node);
+      importElement.importedLibrary = importedLibrary;
+      setElementDocumentationComment(importElement, node);
+      SimpleIdentifier prefixNode = node.prefix;
+      if (prefixNode != null) {
+        importElement.prefixOffset = prefixNode.offset;
+        String prefixName = prefixNode.name;
+        PrefixElementImpl prefix = nameToPrefixMap[prefixName];
+        if (prefix == null) {
+          prefix = new PrefixElementImpl.forNode(prefixNode);
+          nameToPrefixMap[prefixName] = prefix;
         }
-        ImportElementImpl importElement = new ImportElementImpl(node.offset);
-        importElement.metadata = _getElementAnnotations(node.metadata);
-        StringLiteral uriLiteral = node.uri;
+        importElement.prefix = prefix;
+        prefixNode.staticElement = prefix;
+      }
+      node.element = importElement;
+      imports.add(importElement);
+      if (importedTime >= 0 &&
+          importSourceKindMap[importedSource] != SourceKind.LIBRARY) {
+        int offset = node.offset;
+        int length = node.length;
         if (uriLiteral != null) {
-          importElement.uriOffset = uriLiteral.offset;
-          importElement.uriEnd = uriLiteral.end;
-        }
-        importElement.uri = node.uriContent;
-        importElement.deferred = node.deferredKeyword != null;
-        importElement.combinators = _buildCombinators(node);
-        importElement.importedLibrary = importedLibrary;
-        setElementDocumentationComment(importElement, node);
-        SimpleIdentifier prefixNode = node.prefix;
-        if (prefixNode != null) {
-          importElement.prefixOffset = prefixNode.offset;
-          String prefixName = prefixNode.name;
-          PrefixElementImpl prefix = nameToPrefixMap[prefixName];
-          if (prefix == null) {
-            prefix = new PrefixElementImpl.forNode(prefixNode);
-            nameToPrefixMap[prefixName] = prefix;
-          }
-          importElement.prefix = prefix;
-          prefixNode.staticElement = prefix;
-        }
-        node.element = importElement;
-        imports.add(importElement);
-        if (importSourceKindMap[importedSource] != SourceKind.LIBRARY) {
-          int offset = node.offset;
-          int length = node.length;
-          if (uriLiteral != null) {
-            offset = uriLiteral.offset;
-            length = uriLiteral.length;
-          }
-          ErrorCode errorCode = (importElement.isDeferred
-              ? StaticWarningCode.IMPORT_OF_NON_LIBRARY
-              : CompileTimeErrorCode.IMPORT_OF_NON_LIBRARY);
-          errors.add(new AnalysisError(libraryElement.source, offset, length,
-              errorCode, [uriLiteral.toSource()]));
+          offset = uriLiteral.offset;
+          length = uriLiteral.length;
         }
+        ErrorCode errorCode = importElement.isDeferred
+            ? StaticWarningCode.IMPORT_OF_NON_LIBRARY
+            : CompileTimeErrorCode.IMPORT_OF_NON_LIBRARY;
+        errors.add(new AnalysisError(libraryElement.source, offset, length,
+            errorCode, [uriLiteral.toSource()]));
       }
     }
     return null;
@@ -975,8 +974,8 @@ class ElementBuilder extends RecursiveAstVisitor<Object> {
       } else {
         SimpleIdentifier propertyNameNode = node.name;
         String propertyName = propertyNameNode.name;
-        FieldElementImpl field =
-            _currentHolder.getField(propertyName, synthetic: true) as FieldElementImpl;
+        FieldElementImpl field = _currentHolder.getField(propertyName,
+            synthetic: true) as FieldElementImpl;
         if (field == null) {
           field = new FieldElementImpl(node.name.name, -1);
           field.final2 = true;