Compute documentation offsets for library, import, and export directive elements (issue 24756)

pkg/analyzer/lib/src/task/dart.dart

Index: pkg/analyzer/lib/src/task/dart.dart
diff --git a/pkg/analyzer/lib/src/task/dart.dart b/pkg/analyzer/lib/src/task/dart.dart
index ff360386f24a8aec8f976b2285f082673b6cf42e..b358fd36c08e77bc0d674ac7f445fcd93a4331c1 100644
--- a/pkg/analyzer/lib/src/task/dart.dart
+++ b/pkg/analyzer/lib/src/task/dart.dart
@@ -812,6 +812,7 @@ class BuildDirectiveElementsTask extends SourceBasedAnalysisTask {
             importElement.deferred = importDirective.deferredKeyword != null;
             importElement.combinators = _buildCombinators(importDirective);
             importElement.importedLibrary = importedLibrary;
+            _setDocRange(importElement, importDirective);
             SimpleIdentifier prefixNode = directive.prefix;
             if (prefixNode != null) {
               importElement.prefixOffset = prefixNode.offset;
@@ -853,6 +854,7 @@ class BuildDirectiveElementsTask extends SourceBasedAnalysisTask {
             exportElement.uri = exportDirective.uriContent;
             exportElement.combinators = _buildCombinators(exportDirective);
             exportElement.exportedLibrary = exportedLibrary;
+            _setDocRange(exportElement, exportDirective);
             directive.element = exportElement;
             exports.add(exportElement);
             if (exportSourceKindMap[exportedSource] != SourceKind.LIBRARY) {
@@ -893,6 +895,17 @@ class BuildDirectiveElementsTask extends SourceBasedAnalysisTask {
   }
 
   /**
+   * If the given [node] has a documentation comment, remember its range
+   * into the given [element].
+   */
+  void _setDocRange(ElementImpl element, AnnotatedNode node) {
+    Comment comment = node.documentationComment;
+    if (comment != null && comment.isDocumentation) {
+      element.setDocRange(comment.offset, comment.length);
+    }
+  }
+
+  /**
    * Return a map from the names of the inputs of this kind of task to the task
    * input descriptors describing those inputs for a task with the
    * given library [libSource].
@@ -1161,6 +1174,7 @@ class BuildLibraryElementTask extends SourceBasedAnalysisTask {
     //
     // Update "part" directives.
     //
+    LibraryDirective libraryDirective = null;
     LibraryIdentifier libraryNameNode = null;
     String partsLibraryName = _UNKNOWN_LIBRARY_NAME;
     bool hasPartDirective = false;
@@ -1171,7 +1185,8 @@ class BuildLibraryElementTask extends SourceBasedAnalysisTask {
         <CompilationUnitElementImpl>[];
     for (Directive directive in definingCompilationUnit.directives) {
       if (directive is LibraryDirective) {
-        if (libraryNameNode == null) {
+        if (libraryDirective == null) {
+          libraryDirective = directive;
           libraryNameNode = directive.name;
           directivesToResolve.add(directive);
         }
@@ -1255,6 +1270,9 @@ class BuildLibraryElementTask extends SourceBasedAnalysisTask {
     if (sourcedCompilationUnits.isNotEmpty) {
       _patchTopLevelAccessors(libraryElement);
     }
+    if (libraryDirective != null) {
+      _setDocRange(libraryElement, libraryDirective);
+    }
     //
     // Record outputs.
     //
@@ -1341,6 +1359,17 @@ class BuildLibraryElementTask extends SourceBasedAnalysisTask {
   }
 
   /**
+   * If the given [node] has a documentation comment, remember its range
+   * into the given [element].
+   */
+  void _setDocRange(ElementImpl element, AnnotatedNode node) {
+    Comment comment = node.documentationComment;
+    if (comment != null && comment.isDocumentation) {
+      element.setDocRange(comment.offset, comment.length);
+    }
+  }
+
+  /**
    * Return a map from the names of the inputs of this kind of task to the task
    * input descriptors describing those inputs for a task with the given
    * [libSource].
@@ -2125,11 +2154,9 @@ class DartErrorsTask extends SourceBasedAnalysisTask {
       String inputName = result.name + '_input';
       Map<Source, List<AnalysisError>> errorMap = getRequiredInput(inputName);
       for (List<AnalysisError> errors in errorMap.values) {
-        errorLists.add(errors
-            .where((AnalysisError error) {
-              return !filters.any((ErrorFilter filter) => filter(error));
-            })
-            .toList());
+        errorLists.add(errors.where((AnalysisError error) {
+          return !filters.any((ErrorFilter filter) => filter(error));
+        }).toList());
       }
     }
     //