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

 // Copyright (c) 2014, 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.
 
 library analyzer.src.dart.element.builder;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
@@ skipping 136 matching lines @@
     }
     //
     // Ensure "dart:core" import.
     //
     Source librarySource = libraryElement.source;
     Source coreLibrarySource = context.sourceFactory.forUri(DartSdk.DART_CORE);
     if (!explicitlyImportsCore && coreLibrarySource != librarySource) {
       ImportElementImpl importElement = new ImportElementImpl(-1);
       importElement.importedLibrary = importLibraryMap[coreLibrarySource];
       importElement.synthetic = true;
+      importElement.uriExists = true;
       imports.add(importElement);
     }
     //
     // Populate the library element.
     //
     libraryElement.imports = imports;
     libraryElement.exports = exports;
     return null;
   }
 
   @override
   Object visitExportDirective(ExportDirective node) {
     // Remove previous element. (It will remain null if the target is missing.)
     node.element = null;
     Source exportedSource = node.source;
     int exportedTime = sourceModificationTimeMap[exportedSource] ?? -1;
     if (exportedTime != -1) {
       // The exported source will be null if the URI in the export
       // directive was invalid.
       LibraryElement exportedLibrary = exportLibraryMap[exportedSource];
       if (exportedLibrary != null) {
         ExportElementImpl exportElement = new ExportElementImpl(node.offset);
         exportElement.metadata = _getElementAnnotations(node.metadata);
         StringLiteral uriLiteral = node.uri;
         if (uriLiteral != null) {
           exportElement.uriOffset = uriLiteral.offset;
           exportElement.uriEnd = uriLiteral.end;
         }
         exportElement.uri = node.uriContent;
+        exportElement.uriExists = exportedTime >= 0;

[scheglov, 2016/08/09 17:45:04]

We have already checked "exportedTime != -1" above.

Just a note - it seems that we have an asymmetry now - we add unresolved
imports, but don't add unresolved exports.

[Brian Wilkerson, 2016/08/09 18:11:25]

Good catch! The asymmetry was unintentional, so I updated this method to
correspond to visitImportDirective. Nothing else needed to be changed.

         exportElement.combinators = _buildCombinators(node);
         exportElement.exportedLibrary = exportedLibrary;
         setElementDocumentationComment(exportElement, node);
         node.element = exportElement;
         exports.add(exportElement);
         if (exportSourceKindMap[exportedSource] != SourceKind.LIBRARY) {
           int offset = node.offset;
           int length = node.length;
           if (uriLiteral != null) {
             offset = uriLiteral.offset;
@@ skipping 10 matching lines @@
     }
     return null;
   }
 
   @override
   Object visitImportDirective(ImportDirective node) {
     // Remove previous element. (It will remain null if the target is missing.)
     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
+    // 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.uriExists = importedTime >= 0;
+      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;
+          offset = uriLiteral.offset;
+          length = uriLiteral.length;
         }
-        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()]));
-        }
+        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;
   }
 
   @override
   Object visitLibraryDirective(LibraryDirective node) {
     (node.element as LibraryElementImpl)?.metadata =
         _getElementAnnotations(node.metadata);
     return null;
@@ skipping 695 matching lines @@
           element.generator = true;
         }
         if (node.returnType == null) {
           element.hasImplicitReturnType = true;
         }
         _currentHolder.addMethod(element);
         methodName.staticElement = element;
       } 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;
           field.static = isStatic;
           field.synthetic = true;
           _currentHolder.addField(field);
         }
         if (node.isGetter) {
           PropertyAccessorElementImpl getter =
               new PropertyAccessorElementImpl.forNode(propertyNameNode);
@@ skipping 467 matching lines @@
     return null;
   }
 
   /**
    * Return the lexical identifiers associated with the given [identifiers].
    */
   static List<String> _getIdentifiers(NodeList<SimpleIdentifier> identifiers) {
     return identifiers.map((identifier) => identifier.name).toList();
   }
 }