Elements. Migrate JoinVariableDeclaration.

Change-Id: If3290aaeecc8b698dc655755e3da5fe7dc3b26e9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/387356
Reviewed-by: Samuel Rawlins <srawlins@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>

pkg/analysis_server/analyzer_use_new_elements.txt

@@ -305,6 +305,7 @@ lib/src/services/correction/dart/insert_semicolon.dart
 lib/src/services/correction/dart/invert_if_statement.dart
 lib/src/services/correction/dart/join_if_with_inner.dart
 lib/src/services/correction/dart/join_if_with_outer.dart
+lib/src/services/correction/dart/join_variable_declaration.dart
 lib/src/services/correction/dart/make_class_abstract.dart
 lib/src/services/correction/dart/make_conditional_on_debug_mode.dart
 lib/src/services/correction/dart/make_field_public.dart

pkg/analysis_server/lib/src/services/correction/dart/join_variable_declaration.dart

@@ -82,7 +82,7 @@ class JoinVariableDeclaration extends ResolvedCorrectionProducer {
     // The declared variable must be the one that is assigned.
     // There must be no initializer.
     var declaredVariable = declaredVariables.single;
-    if (declaredVariable.declaredElement != left.staticElement ||
+    if (declaredVariable.declaredElement2 != left.element ||
         declaredVariable.initializer != null) {
       return;
     }
@@ -144,7 +144,7 @@ class JoinVariableDeclaration extends ResolvedCorrectionProducer {
     }
 
     // The assignment should write into the declared variable.
-    if (assignment.writeElement != declaredVariable.declaredElement) {
+    if (assignment.writeElement2 != declaredVariable.declaredElement2) {
       return;
     }