TBR Revert "Remove MemberMap in favor of HashMap"

pkg/analyzer/lib/src/generated/error_verifier.dart

Index: pkg/analyzer/lib/src/generated/error_verifier.dart
diff --git a/pkg/analyzer/lib/src/generated/error_verifier.dart b/pkg/analyzer/lib/src/generated/error_verifier.dart
index ecc2dae67065d9dc33df328570f746cf3acb11f2..8fa08b58b9f410bd0f509cbad4423d6bf715b236 100644
--- a/pkg/analyzer/lib/src/generated/error_verifier.dart
+++ b/pkg/analyzer/lib/src/generated/error_verifier.dart
@@ -4526,15 +4526,17 @@ class ErrorVerifier extends RecursiveAstVisitor<Object> {
     // Loop through the set of all executable elements declared in the implicit
     // interface.
     //
-    Map<String, ExecutableElement> membersInheritedFromInterfaces =
-        _inheritanceManager
-            .getMapOfMembersInheritedFromInterfaces(_enclosingClass);
-    Map<String, ExecutableElement> membersInheritedFromSuperclasses =
-        _inheritanceManager
-            .getMapOfMembersInheritedFromClasses(_enclosingClass);
-    for (String memberName in membersInheritedFromInterfaces.keys) {
+    MemberMap membersInheritedFromInterfaces = _inheritanceManager
+        .getMapOfMembersInheritedFromInterfaces(_enclosingClass);
+    MemberMap membersInheritedFromSuperclasses = _inheritanceManager
+        .getMapOfMembersInheritedFromClasses(_enclosingClass);
+    for (int i = 0; i < membersInheritedFromInterfaces.size; i++) {
+      String memberName = membersInheritedFromInterfaces.getKey(i);
       ExecutableElement executableElt =
-          membersInheritedFromInterfaces[memberName];
+          membersInheritedFromInterfaces.getValue(i);
+      if (memberName == null) {
+        break;
+      }
       // If the element is not synthetic and can be determined to be defined in
       // Object, skip it.
       if (executableElt.enclosingElement != null &&
@@ -4552,7 +4554,7 @@ class ErrorVerifier extends RecursiveAstVisitor<Object> {
       }
       // First check to see if this element was declared in the superclass
       // chain, in which case there is already a concrete implementation.
-      ExecutableElement elt = membersInheritedFromSuperclasses[memberName];
+      ExecutableElement elt = membersInheritedFromSuperclasses.get(memberName);
       // Check to see if an element was found in the superclass chain with the
       // correct name.
       if (elt != null) {