Index: clang/lib/Sema/SemaLookup.cpp
===================================================================
--- clang/lib/Sema/SemaLookup.cpp
+++ clang/lib/Sema/SemaLookup.cpp
@@ -1313,6 +1313,9 @@
             R.setShadowed();
             continue;
           }
+        } else if (NameKind == LookupObjCImplicitSelfParam &&
+                   !isa<ImplicitParamDecl>(*I)) {
+          continue;
         } else {
           // We found something in this scope, we should not look at the
           // namespace scope
Index: clang/unittests/Sema/SemaLookupTest.cpp
===================================================================
--- clang/unittests/Sema/SemaLookupTest.cpp
+++ clang/unittests/Sema/SemaLookupTest.cpp
@@ -1,4 +1,6 @@
 #include "clang/AST/DeclarationName.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/FrontendAction.h"
 #include "clang/Parse/ParseAST.h"
@@ -10,6 +12,7 @@
 using namespace llvm;
 using namespace clang;
 using namespace clang::tooling;
+using namespace clang::ast_matchers;
 
 namespace {
 
@@ -57,4 +60,84 @@
                                     file_contents, {"-x", "objective-c++"},
                                     "test.mm"));
 }
+
+using ExprMatcher = internal::Matcher<Expr>;
+using StmtMatcher = internal::Matcher<Stmt>;
+
+AST_MATCHER(ObjCIvarRefExpr, isFreeIvar) {
+  return Node.isFreeIvar();
+}
+
+ExprMatcher objcIvarRefTo(StringRef Name) {
+  return declRefExpr(hasAncestor(objcIvarRefExpr(allOf(isFreeIvar(),
+                                                       hasDeclaration(namedDecl(
+                                                           hasName(Name)))))
+                                     .bind("ivarref")))
+      .bind("selfref");
+}
+
+StmtMatcher withEnclosingMethod(ExprMatcher Matcher) {
+  return expr(Matcher,
+              hasAncestor(objcMethodDecl(isDefinition()).bind("method")))
+      .bind("expr");
+}
+
+class IvarLookupImplicitSelf : public ASTFrontendAction {
+  std::unique_ptr<ASTConsumer>
+  CreateASTConsumer(CompilerInstance &CI, StringRef /* Unused */) override {
+    return std::make_unique<clang::ASTConsumer>();
+  }
+
+  void ExecuteAction() override {
+    CompilerInstance &CI = getCompilerInstance();
+    ASSERT_FALSE(CI.hasSema());
+    CI.createSema(getTranslationUnitKind(), nullptr);
+    ASSERT_TRUE(CI.hasSema());
+    Sema &S = CI.getSema();
+    ParseAST(S);
+
+    ASTContext &Ctx = S.getASTContext();
+    const auto Results =
+        match(withEnclosingMethod(objcIvarRefTo("_ivar")), Ctx);
+    const auto *MD = selectFirst<ObjCMethodDecl>("method", Results);
+    const auto *SelfRef = selectFirst<DeclRefExpr>("selfref", Results);
+    ASSERT_TRUE(MD && SelfRef);
+
+    // When name lookup is occurring correctly, the SelfRef should refer to the
+    // Method's ImplicitParamDecl of 'self'.
+    const auto *SelfDecl = SelfRef->getDecl();
+    EXPECT_TRUE(isa<ImplicitParamDecl>(SelfDecl) &&
+                MD->getSelfDecl() == SelfDecl);
+  }
+};
+
+constexpr StringRef ImplicitIvarFileContents = R"objcxx(
+__attribute__((objc_root_class))
+@interface Foo
+@end
+extern Foo *CreateFoo();
+@implementation Foo {
+  int _ivar;
+}
+- (void)foo {
+  {
+    Foo *self = CreateFoo();
+    _ivar = 42;
+  }
+}
+@end
+  )objcxx";
+
+TEST(SemaLookupTest, ImplicitIvarSelfRefLookupObjCpp) {
+  ASSERT_TRUE(runToolOnCodeWithArgs(std::make_unique<IvarLookupImplicitSelf>(),
+                                    ImplicitIvarFileContents,
+                                    {"-x", "objective-c++"}, "test.mm"));
+}
+
+TEST(SemaLookupTest, ImplicitIvarSelfRefLookupObjC) {
+  ASSERT_TRUE(runToolOnCodeWithArgs(std::make_unique<IvarLookupImplicitSelf>(),
+                                    ImplicitIvarFileContents,
+                                    {"-x", "objective-c"}, "test.m"));
+}
+
 } // namespace