Use CompilationUnitElement.lineInfo instead of AnalysisContext.

pkg/analysis_server/lib/src/protocol_server.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 protocol.server;
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/plugin/protocol/protocol_dart.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart'
@@ skipping 115 matching lines @@
   String correction = error.correction;
   bool fix = hasFix(error.errorCode);
   return new AnalysisError(severity, type, location, message, code,
       correction: correction, hasFix: fix);
 }
 
 /**
  * Create a Location based on an [engine.Element].
  */
 Location newLocation_fromElement(engine.Element element) {
-  engine.AnalysisContext context = element.context;
-  engine.Source source = element.source;
-  if (context == null || source == null) {
+  if (element == null || element.source == null) {
     return null;
   }
   int offset = element.nameOffset;
   int length = element.nameLength;
   if (element is engine.CompilationUnitElement ||
       (element is engine.LibraryElement && offset < 0)) {
     offset = 0;
     length = 0;
   }
+  engine.CompilationUnitElement unitElement = _getUnitElement(element);
   engine.SourceRange range = new engine.SourceRange(offset, length);
-  return _locationForArgs(context, source, range);
+  return _locationForArgs(unitElement, range);
 }
 
 /**
  * Create a Location based on an [engine.SearchMatch].
  */
 Location newLocation_fromMatch(engine.SearchMatch match) {
-  engine.Element enclosingElement = match.element;
-  return _locationForArgs(
-      enclosingElement.context, enclosingElement.source, match.sourceRange);
+  engine.CompilationUnitElement unitElement = _getUnitElement(match.element);
+  return _locationForArgs(unitElement, match.sourceRange);
 }
 
 /**
  * Create a Location based on an [engine.AstNode].
  */
 Location newLocation_fromNode(engine.AstNode node) {
   engine.CompilationUnit unit =
       node.getAncestor((node) => node is engine.CompilationUnit);
   engine.CompilationUnitElement unitElement = unit.element;
-  engine.AnalysisContext context = unitElement.context;
-  engine.Source source = unitElement.source;
   engine.SourceRange range = new engine.SourceRange(node.offset, node.length);
-  return _locationForArgs(context, source, range);
+  return _locationForArgs(unitElement, range);
 }
 
 /**
  * Create a Location based on an [engine.CompilationUnit].
  */
 Location newLocation_fromUnit(
     engine.CompilationUnit unit, engine.SourceRange range) {
-  engine.CompilationUnitElement unitElement = unit.element;
-  engine.AnalysisContext context = unitElement.context;
-  engine.Source source = unitElement.source;
-  return _locationForArgs(context, source, range);
+  return _locationForArgs(unit.element, range);
 }
 
 /**
  * Construct based on an element from the analyzer engine.
  */
 OverriddenMember newOverriddenMember_fromEngine(engine.Element member) {
   Element element = convertElement(member);
   String className = member.enclosingElement.displayName;
   return new OverriddenMember(element, className);
 }
@@ skipping 50 matching lines @@
       // imports are library children, but they are physically in the unit
       engine.LibraryElement library = element.enclosingElement;
       element = library.definingCompilationUnit;
     } else {
       element = element.enclosingElement;
     }
   }
   return path;
 }
 
+engine.CompilationUnitElement _getUnitElement(engine.Element element) {
+  if (element is engine.CompilationUnitElement) {
+    return element;
+  }
+  if (element?.enclosingElement is engine.LibraryElement) {
+    element = element.enclosingElement;
+  }
+  if (element is engine.LibraryElement) {
+    return element.definingCompilationUnit;
+  }
+  for (; element != null; element = element.enclosingElement) {
+    if (element is engine.CompilationUnitElement) {
+      return element;
+    }
+  }
+  return null;
+}
+
 /**
  * Creates a new [Location].
  */
-Location _locationForArgs(engine.AnalysisContext context, engine.Source source,
-    engine.SourceRange range) {
+Location _locationForArgs(
+    engine.CompilationUnitElement unitElement, engine.SourceRange range) {
   int startLine = 0;
   int startColumn = 0;
   try {
-    engine.LineInfo lineInfo = context.computeLineInfo(source);
+    engine.LineInfo lineInfo = unitElement.lineInfo;
     if (lineInfo != null) {
       engine.LineInfo_Location offsetLocation =
           lineInfo.getLocation(range.offset);
       startLine = offsetLocation.lineNumber;
       startColumn = offsetLocation.columnNumber;
     }
   } on AnalysisException {}
-  return new Location(
-      source.fullName, range.offset, range.length, startLine, startColumn);
+  return new Location(unitElement.source.fullName, range.offset, range.length,
+      startLine, startColumn);
 }