Elements. Store LocalVariableElementImpl.type, don't get from the fragment.

Eventually VariableFragmentImpl.type will become nullable, with the
meaning that if it is specified, it has value, otherwise it is `null`.
And `VariableElementImpl.type` will be non-nullable, inferred if necessary.

Change-Id: If20c037f46ffb6861a11b945089dcf1d5b77dc40
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/438487
Commit-Queue: Konstantin Shcheglov <[email protected]>
Reviewed-by: Paul Berry <[email protected]>

Author: scheglov

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

@@ -6803,6 +6803,9 @@ class LocalVariableElementImpl extends PromotableElementImpl
   @override
   final LocalVariableFragmentImpl _wrappedElement;
 
+  @override
+  TypeImpl type = InvalidTypeImpl.instance;
+
   LocalVariableElementImpl(this._wrappedElement);
 
   @override
@@ -6854,11 +6857,6 @@ class LocalVariableElementImpl extends PromotableElementImpl
   @override
   MetadataImpl get metadata2 => metadata;
 
-  @override
-  TypeImpl get type => _wrappedElement.type;
-
-  set type(TypeImpl type) => _wrappedElement.type = type;
-
   LocalVariableFragmentImpl get wrappedElement {
     return _wrappedElement;
   }
@@ -6874,6 +6872,19 @@ class LocalVariableElementImpl extends PromotableElementImpl
   @Deprecated('Use accept instead')
   @override
   T? accept2<T>(ElementVisitor2<T> visitor) => accept(visitor);
+
+  @override
+  String displayString2({
+    bool multiline = false,
+    bool preferTypeAlias = false,
+  }) {
+    var builder = ElementDisplayStringBuilder(
+      multiline: multiline,
+      preferTypeAlias: preferTypeAlias,
+    );
+    builder.writeVariableElement2(this);
+    return builder.toString();
+  }
 }
 
 class LocalVariableFragmentImpl extends NonParameterVariableFragmentImpl
@@ -10126,6 +10137,10 @@ abstract class VariableFragmentImpl extends FragmentImpl
     _type = type;
   }
 
+  /// The declared type of this variable.
+  // TODO(scheglov): turn into field
+  TypeImpl? get type2 => _type;
+
   @override
   void appendTo(ElementDisplayStringBuilder builder) {
     builder.writeVariableElement(this);

pkg/analyzer/lib/src/dart/resolver/resolution_visitor.dart

@@ -244,9 +244,10 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
         fragment.isFinal = true;
         if (exceptionTypeNode == null) {
           fragment.hasImplicitType = true;
-          fragment.type = _typeProvider.objectType;
+          fragment.element.type = _typeProvider.objectType;
         } else {
           fragment.type = exceptionTypeNode.typeOrThrow;
+          fragment.element.type = exceptionTypeNode.typeOrThrow;
         }
 
         fragment.setCodeRange(
@@ -267,7 +268,8 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
         stackTraceNode.declaredFragment = fragment;
 
         fragment.isFinal = true;
-        fragment.type = _typeProvider.stackTraceType;
+        fragment.hasImplicitType = true;
+        fragment.element.type = _typeProvider.stackTraceType;
 
         fragment.setCodeRange(
           stackTraceNode.name.offset,
@@ -391,12 +393,13 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
     fragment.isConst = node.isConst;
     fragment.isFinal = node.isFinal;
 
-    if (node.type == null) {
-      fragment.hasImplicitType = true;
-      fragment.type = _dynamicType;
+    if (node.type case var typeNode?) {
+      typeNode.accept(this);
+      fragment.type = typeNode.typeOrThrow;
+      fragment.element.type = typeNode.typeOrThrow;
     } else {
-      node.type!.accept(this);
-      fragment.type = node.type!.typeOrThrow;
+      fragment.hasImplicitType = true;
+      fragment.element.type = _dynamicType;
     }
 
     _setCodeRange(fragment, node);
@@ -418,7 +421,10 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
     _elementHolder.enclose(fragment);
     _define(fragment.element);
     fragment.hasImplicitType = node.type == null;
-    fragment.type = node.type?.type ?? InvalidTypeImpl.instance;
+    if (node.type case var typeNode?) {
+      fragment.type = typeNode.typeOrThrow;
+      fragment.element.type = typeNode.typeOrThrow;
+    }
     node.declaredFragment = fragment;
 
     var patternContext = node.patternContext;
@@ -1419,13 +1425,19 @@ class ResolutionVisitor extends RecursiveAstVisitor<void> {
       fragment = _elementWalker!.getVariable();
       node.declaredFragment = fragment;
     } else {
-      var localElement = node.declaredFragment as LocalVariableFragmentImpl;
-      fragment = localElement;
+      var localFragment = node.declaredFragment as LocalVariableFragmentImpl;
+      fragment = localFragment;
 
       var varList = node.parent as VariableDeclarationListImpl;
-      localElement.hasImplicitType = varList.type == null;
-      localElement.hasInitializer = initializerNode != null;
-      localElement.type = varList.type?.type ?? _dynamicType;
+      localFragment.hasInitializer = initializerNode != null;
+      if (varList.type case var typeNode?) {
+        var type = typeNode.typeOrThrow;
+        localFragment.type = type;
+        localFragment.element.type = type;
+      } else {
+        localFragment.hasImplicitType = true;
+        localFragment.element.type = _dynamicType;
+      }
     }
 
     if (initializerNode != null) {

pkg/analyzer/test/src/dart/resolution/try_statement_test.dart

@@ -84,8 +84,8 @@ TryStatement
       stackTraceParameter: CatchClauseParameter
         name: y
         declaredFragment: isFinal isPublic y@30
-          type: StackTrace
-          element: isFinal isPublic
+          type: null
+          element: hasImplicitType isFinal isPublic
             type: StackTrace
       rightParenthesis: )
       body: Block
@@ -128,8 +128,8 @@ TryStatement
       stackTraceParameter: CatchClauseParameter
         name: st
         declaredFragment: isFinal isPublic st@31
-          type: StackTrace
-          element: isFinal isPublic
+          type: null
+          element: hasImplicitType isFinal isPublic
             type: StackTrace
       rightParenthesis: )
       body: Block
@@ -172,8 +172,8 @@ TryStatement
       stackTraceParameter: CatchClauseParameter
         name: st
         declaredFragment: isFinal isPublic st@31
-          type: StackTrace
-          element: isFinal isPublic
+          type: null
+          element: hasImplicitType isFinal isPublic
             type: StackTrace
       rightParenthesis: )
       body: Block
@@ -213,8 +213,8 @@ TryStatement
       stackTraceParameter: CatchClauseParameter
         name: st
         declaredFragment: isFinal isPublic st@30
-          type: StackTrace
-          element: isFinal isPublic
+          type: null
+          element: hasImplicitType isFinal isPublic
             type: StackTrace
       rightParenthesis: )
       body: Block
@@ -259,8 +259,8 @@ TryStatement
       stackTraceParameter: CatchClauseParameter
         name: st
         declaredFragment: isFinal isPublic st@37
-          type: StackTrace
-          element: isFinal isPublic
+          type: null
+          element: hasImplicitType isFinal isPublic
             type: StackTrace
       rightParenthesis: )
       body: Block

pkg/analyzer/test/src/summary/resolved_ast_printer.dart

@@ -1786,12 +1786,7 @@ Expected parent: (${parent.runtimeType}) $parent
     });
 
     _sink.withIndent(() {
-      if (fragment.hasImplicitType) {
-        // TODO(scheglov): eventually we can just write type a below.
-        _sink.writelnWithIndent('type: null');
-      } else {
-        _writeType('type', fragment.type);
-      }
+      _writeType('type', fragment.type2);
 
       var element = fragment.element;
       _sink.writeIndentedLine(() {