DeCo. Stop using isSynthetic in index.

There is no change in behavior. Index record relations between elements
and locations, where the element is identified by a triplet of names
(topLevelName, classMemberName, formalParameterName). Which is almost
enough, but for field / getter / setter the names are the same, so we
add the kind. It was more complicated than necessary, so I simplified
it a little.

Change-Id: If91b8881f89ffc7a8f41331ded9ef4b1b64136b8
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/465965
Reviewed-by: Paul Berry <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>

Author: scheglov

pkg/analyzer/lib/src/dart/analysis/driver.dart

@@ -108,7 +108,7 @@ testFineAfterLibraryAnalyzerHook;
 // TODO(scheglov): Clean up the list of implicitly analyzed files.
 class AnalysisDriver {
   /// The version of data format, should be incremented on every format change.
-  static const int DATA_VERSION = 592;
+  static const int DATA_VERSION = 593;
 
   /// The number of exception contexts allowed to write. Once this field is
   /// zero, we stop writing any new exception contexts in this process.

pkg/analyzer/lib/src/dart/analysis/index.dart

@@ -173,55 +173,14 @@ class IndexElementInfo {
 
   factory IndexElementInfo(Element element) {
     IndexSyntheticElementKind kind = IndexSyntheticElementKind.notSynthetic;
-    ElementKind elementKind = element.kind;
-    if (elementKind == ElementKind.LIBRARY ||
-        elementKind == ElementKind.COMPILATION_UNIT) {
-      kind = IndexSyntheticElementKind.unit;
-    } else if (element.isSynthetic) {
-      if (elementKind == ElementKind.CONSTRUCTOR) {
-        kind = IndexSyntheticElementKind.constructor;
-        element = element.enclosingElement!;
-      } else if (element is TopLevelFunctionElement &&
-          element.name == TopLevelFunctionElement.LOAD_LIBRARY_NAME) {
-        kind = IndexSyntheticElementKind.loadLibrary;
-        element = element.library;
-      } else if (elementKind == ElementKind.FIELD) {
-        var field = element as FieldElement;
-        kind = IndexSyntheticElementKind.field;
-        element = (field.getter ?? field.setter)!;
-      } else if (elementKind == ElementKind.GETTER ||
-          elementKind == ElementKind.SETTER) {
-        var accessor = element as PropertyAccessorElement;
-        var enclosing = element.enclosingElement;
-        bool isEnumGetter = enclosing is EnumElement;
-        if (isEnumGetter && accessor.name == 'index') {
-          kind = IndexSyntheticElementKind.enumIndex;
-          element = enclosing;
-        } else if (isEnumGetter && accessor.name == 'values') {
-          kind = IndexSyntheticElementKind.enumValues;
-          element = enclosing;
-        } else {
-          kind = accessor is GetterElement
-              ? IndexSyntheticElementKind.getter
-              : IndexSyntheticElementKind.setter;
-          element = accessor.variable;
-        }
-      } else if (element is MethodElement) {
-        var enclosing = element.enclosingElement;
-        bool isEnumMethod = enclosing is EnumElement;
-        if (isEnumMethod && element.name == 'toString') {
-          kind = IndexSyntheticElementKind.enumToString;
-          element = enclosing;
-        }
-      } else if (element is TopLevelVariableElement) {
-        kind = IndexSyntheticElementKind.topLevelVariable;
-        element = (element.getter ?? element.setter)!;
-      } else {
-        throw ArgumentError(
-          'Unsupported synthetic element ${element.runtimeType}',
-        );
-      }
+    if (element is GetterElement) {
+      kind = IndexSyntheticElementKind.getter;
+      element = element.variable;
+    } else if (element is SetterElement) {
+      kind = IndexSyntheticElementKind.setter;
+      element = element.variable;
     }
+
     return IndexElementInfo._(element, kind);
   }
 
@@ -657,10 +616,8 @@ class _IndexContributor extends GeneralizingAstVisitor {
     }
     // Ignore named parameters of synthetic functions, e.g. created for LUB.
     // These functions are not bound to a source, we cannot index them.
-    if (elementKind == ElementKind.PARAMETER &&
-        element is FormalParameterElement) {
-      var enclosingElement = element.enclosingElement;
-      if (enclosingElement == null || enclosingElement.isSynthetic) {
+    if (element is FormalParameterElement) {
+      if (element.enclosingElement == null) {
         return;
       }
     }