Forward compatible portion of CL that does not set types for identifiers that are not expressions.

The full CL:
https://dart-review.googlesource.com/c/sdk/+/119761

Change-Id: I9c909a4e1eec5d05f5718849ea45da79f01c5291
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/121643
Reviewed-by: Paul Berry <paulberry@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>

Author: scheglov

pkg/analysis_server/lib/src/computer/computer_highlights.dart

@@ -141,18 +141,15 @@ class DartUnitHighlightsComputer {
   }
 
   bool _addIdentifierRegion_dynamicType(SimpleIdentifier node) {
-    // should be variable
     Element element = node.staticElement;
-    if (element is! VariableElement) {
-      return false;
-    }
-    // has dynamic static type
-    DartType staticType = node.staticType;
-    if (staticType == null || !staticType.isDynamic) {
-      return false;
+    if (element is VariableElement) {
+      DartType staticType = element.type;
+      if (staticType == null || !staticType.isDynamic) {
+        return false;
+      }
+      return _addRegion_node(node, HighlightRegionType.DYNAMIC_TYPE);
     }
-    // OK
-    return _addRegion_node(node, HighlightRegionType.DYNAMIC_TYPE);
+    return false;
   }
 
   bool _addIdentifierRegion_field(SimpleIdentifier node) {

pkg/analysis_server/lib/src/computer/computer_highlights2.dart

@@ -144,24 +144,24 @@ class DartUnitHighlightsComputer2 {
   }
 
   bool _addIdentifierRegion_dynamicLocal(SimpleIdentifier node) {
-    // has dynamic static type
-    DartType staticType = node.staticType;
-    if (staticType == null || !staticType.isDynamic) {
-      return false;
-    }
-    // OK
     Element element = node.staticElement;
     if (element is LocalVariableElement) {
-      HighlightRegionType type = node.inDeclarationContext()
-          ? HighlightRegionType.DYNAMIC_LOCAL_VARIABLE_DECLARATION
-          : HighlightRegionType.DYNAMIC_LOCAL_VARIABLE_REFERENCE;
-      return _addRegion_node(node, type);
+      var elementType = element.type;
+      if (elementType?.isDynamic == true) {
+        HighlightRegionType type = node.inDeclarationContext()
+            ? HighlightRegionType.DYNAMIC_LOCAL_VARIABLE_DECLARATION
+            : HighlightRegionType.DYNAMIC_LOCAL_VARIABLE_REFERENCE;
+        return _addRegion_node(node, type);
+      }
     }
     if (element is ParameterElement) {
-      HighlightRegionType type = node.inDeclarationContext()
-          ? HighlightRegionType.DYNAMIC_PARAMETER_DECLARATION
-          : HighlightRegionType.DYNAMIC_PARAMETER_REFERENCE;
-      return _addRegion_node(node, type);
+      var elementType = element.type;
+      if (elementType?.isDynamic == true) {
+        HighlightRegionType type = node.inDeclarationContext()
+            ? HighlightRegionType.DYNAMIC_PARAMETER_DECLARATION
+            : HighlightRegionType.DYNAMIC_PARAMETER_REFERENCE;
+        return _addRegion_node(node, type);
+      }
     }
     return false;
   }

pkg/analysis_server/lib/src/computer/computer_hover.dart

@@ -111,11 +111,9 @@ class DartUnitHoverComputer {
       // types
       {
         AstNode parent = expression.parent;
-        DartType staticType = null;
-        if (element is ParameterElement) {
-          staticType = element.type;
-        } else if (element == null || element is VariableElement) {
-          staticType = expression.staticType;
+        DartType staticType;
+        if (element == null || element is VariableElement) {
+          staticType = _getTypeOfDeclarationOrReference(node);
         }
         if (parent is MethodInvocation && parent.methodName == expression) {
           staticType = parent.staticInvokeType;
@@ -166,5 +164,21 @@ class DartUnitHoverComputer {
     return null;
   }
 
+  static DartType _getTypeOfDeclarationOrReference(Expression node) {
+    if (node is SimpleIdentifier) {
+      var element = node.staticElement;
+      if (element is VariableElement) {
+        if (node.inDeclarationContext()) {
+          return element.type;
+        }
+        var parent2 = node.parent.parent;
+        if (parent2 is NamedExpression && parent2.name.label == node) {
+          return element.type;
+        }
+      }
+    }
+    return node.staticType;
+  }
+
   static String _safeToString(obj) => obj?.toString();
 }

pkg/analysis_server/lib/src/domains/analysis/navigation_dart.dart

@@ -184,7 +184,7 @@ class _DartNavigationComputerVisitor extends RecursiveAstVisitor {
     if (node.type == null) {
       Token token = node.keyword;
       if (token?.keyword == Keyword.VAR) {
-        DartType inferredType = node.identifier?.staticType;
+        DartType inferredType = node.declaredElement?.type;
         Element element = inferredType?.element;
         if (element != null) {
           computer._addRegionForToken(token, element);
@@ -294,12 +294,12 @@ class _DartNavigationComputerVisitor extends RecursiveAstVisitor {
      * inferred type.
      */
     Element getCommonElement(List<VariableDeclaration> variables) {
-      Element firstElement = variables[0].name?.staticType?.element;
+      Element firstElement = variables[0].declaredElement.type?.element;
       if (firstElement == null) {
         return null;
       }
       for (int i = 1; i < variables.length; i++) {
-        Element element = variables[1].name?.staticType?.element;
+        Element element = variables[1].declaredElement.type?.element;
         if (element != firstElement) {
           return null;
         }

pkg/analysis_server/lib/src/services/completion/dart/common_usage_sorter.dart

@@ -57,14 +57,11 @@ class CommonUsageSorter implements DartContributionSorter {
     var target = _getCompletionTarget(request);
     if (target != null) {
       var visitor = new _BestTypeVisitor(target.entity);
-      DartType type = target.containingNode.accept(visitor);
-      if (type != null) {
-        Element typeElem = type.element;
-        if (typeElem != null) {
-          LibraryElement libElem = typeElem.library;
-          if (libElem != null) {
-            _updateInvocationRelevance(type, libElem, suggestions);
-          }
+      var typeElem = target.containingNode.accept(visitor);
+      if (typeElem != null) {
+        LibraryElement libElem = typeElem.library;
+        if (libElem != null) {
+          _updateInvocationRelevance(typeElem.name, libElem, suggestions);
         }
       }
     }
@@ -74,9 +71,8 @@ class CommonUsageSorter implements DartContributionSorter {
    * Adjusts the relevance of all method suggestions based upon the given
    * target type and library.
    */
-  void _updateInvocationRelevance(DartType type, LibraryElement libElem,
+  void _updateInvocationRelevance(String typeName, LibraryElement libElem,
       Iterable<CompletionSuggestion> suggestions) {
-    String typeName = type.name;
     List<String> selectors = selectorRelevance['${libElem.name}.$typeName'];
     if (selectors != null) {
       for (CompletionSuggestion suggestion in suggestions) {
@@ -102,7 +98,7 @@ class CommonUsageSorter implements DartContributionSorter {
 /**
  * An [AstVisitor] used to determine the best defining type of a node.
  */
-class _BestTypeVisitor extends UnifyingAstVisitor<DartType> {
+class _BestTypeVisitor extends UnifyingAstVisitor<Element> {
   /**
    * The entity which the completed text will replace (or which will be
    * displaced once the completed text is inserted).  This may be an AstNode or
@@ -114,32 +110,43 @@ class _BestTypeVisitor extends UnifyingAstVisitor<DartType> {
   _BestTypeVisitor(this.entity);
 
   @override
-  DartType visitConstructorName(ConstructorName node) =>
-      node.period != null && node.name == entity ? node.type?.type : null;
+  Element visitConstructorName(ConstructorName node) {
+    return node.period != null && node.name == entity
+        ? node.type?.type?.element
+        : null;
+  }
 
   @override
-  DartType visitNamedExpression(NamedExpression node) {
+  Element visitNamedExpression(NamedExpression node) {
     AstNode parent = node.parent;
     if (parent is ArgumentListImpl) {
       List<ParameterElement> params = parent.correspondingStaticParameters;
       if (params != null) {
         int index = parent.arguments.indexOf(node);
-        return params[index]?.type;
+        return params[index]?.type?.element;
       }
     }
     return super.visitNamedExpression(node);
   }
 
   @override
-  DartType visitNode(AstNode node) {
+  Element visitNode(AstNode node) {
     return null;
   }
 
   @override
-  DartType visitPrefixedIdentifier(PrefixedIdentifier node) =>
-      node.identifier == entity ? node.prefix?.staticType : null;
+  Element visitPrefixedIdentifier(PrefixedIdentifier node) {
+    if (node.identifier == entity) {
+      var type = node.prefix.staticType;
+      if (type is InterfaceType) {
+        return type.element;
+      }
+      return node.prefix.staticElement;
+    }
+    return null;
+  }
 
   @override
-  DartType visitPropertyAccess(PropertyAccess node) =>
-      node.propertyName == entity ? node.realTarget?.staticType : null;
+  Element visitPropertyAccess(PropertyAccess node) =>
+      node.propertyName == entity ? node.realTarget?.staticType?.element : null;
 }