4 files changed, 49 insertions, 6 deletions

diff --git a/include/clang/Sema/SemaInternal.h b/include/clang/Sema/SemaInternal.h
index 045bacf213..005d882c34 100644
--- a/include/clang/Sema/SemaInternal.h
+++ b/include/clang/Sema/SemaInternal.h
@@ -101,7 +101,7 @@ public:
                          DeclContext *MemberContext,
                          bool EnteringContext)
       : Typo(TypoName.getName().getAsIdentifierInfo()), CurrentTCIndex(0),
-        SemaRef(SemaRef), S(S),
+        SavedTCIndex(0), SemaRef(SemaRef), S(S),
         SS(SS ? llvm::make_unique<CXXScopeSpec>(*SS) : nullptr),
         CorrectionValidator(std::move(CCC)), MemberContext(MemberContext),
         Result(SemaRef, TypoName, LookupKind),
@@ -187,6 +187,17 @@ public:
            CurrentTCIndex >= ValidatedCorrections.size();
   }
 
+  /// \brief Save the current position in the correction stream (overwriting any
+  /// previously saved position).
+  void saveCurrentPosition() {
+    SavedTCIndex = CurrentTCIndex;
+  }
+
+  /// \brief Restore the saved position in the correction stream.
+  void restoreSavedPosition() {
+    CurrentTCIndex = SavedTCIndex;
+  }
+
   ASTContext &getContext() const { return SemaRef.Context; }
   const LookupResult &getLookupResult() const { return Result; }
 
@@ -267,6 +278,7 @@ private:
 
   SmallVector<TypoCorrection, 4> ValidatedCorrections;
   size_t CurrentTCIndex;
+  size_t SavedTCIndex;
 
   Sema &SemaRef;
   Scope *S;
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 9cb147f878..93b4c30871 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -9457,6 +9457,18 @@ static void checkObjCPointerIntrospection(Sema &S, ExprResult &L, ExprResult &R,
   }
 }
 
+static NamedDecl *getDeclFromExpr(Expr *E) {
+  if (!E)
+    return nullptr;
+  if (auto *DRE = dyn_cast<DeclRefExpr>(E))
+    return DRE->getDecl();
+  if (auto *ME = dyn_cast<MemberExpr>(E))
+    return ME->getMemberDecl();
+  if (auto *IRE = dyn_cast<ObjCIvarRefExpr>(E))
+    return IRE->getDecl();
+  return nullptr;
+}
+
 /// CreateBuiltinBinOp - Creates a new built-in binary operation with
 /// operator @p Opc at location @c TokLoc. This routine only supports
 /// built-in operations; ActOnBinOp handles overloaded operators.
@@ -9494,7 +9506,13 @@ ExprResult Sema::CreateBuiltinBinOp(SourceLocation OpLoc,
     // doesn't handle dependent types properly, so make sure any TypoExprs have
     // been dealt with before checking the operands.
     LHS = CorrectDelayedTyposInExpr(LHSExpr);
-    RHS = CorrectDelayedTyposInExpr(RHSExpr);
+    RHS = CorrectDelayedTyposInExpr(RHSExpr, [Opc, LHS](Expr *E) {
+      if (Opc != BO_Assign)
+        return ExprResult(E);
+      // Avoid correcting the RHS to the same Expr as the LHS.
+      Decl *D = getDeclFromExpr(E);
+      return (D && D == getDeclFromExpr(LHS.get())) ? ExprError() : E;
+    });
     if (!LHS.isUsable() || !RHS.isUsable())
       return ExprError();
   }
diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index 49a579fb76..ca15550768 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -6162,15 +6162,18 @@ public:
     while (!AmbiguousTypoExprs.empty()) {
       auto TE  = AmbiguousTypoExprs.back();
       auto Cached = TransformCache[TE];
-      AmbiguousTypoExprs.pop_back();
+      auto &State = SemaRef.getTypoExprState(TE);
+      State.Consumer->saveCurrentPosition();
       TransformCache.erase(TE);
       if (!TryTransform(E).isInvalid()) {
-        SemaRef.getTypoExprState(TE).Consumer->resetCorrectionStream();
+        State.Consumer->resetCorrectionStream();
         TransformCache.erase(TE);
         Res = ExprError();
         break;
-      } else
-        TransformCache[TE] = Cached;
+      }
+      AmbiguousTypoExprs.remove(TE);
+      State.Consumer->restoreSavedPosition();
+      TransformCache[TE] = Cached;
     }
 
     // Ensure that all of the TypoExprs within the current Expr have been found.
diff --git a/test/SemaCXX/typo-correction-delayed.cpp b/test/SemaCXX/typo-correction-delayed.cpp
index c5c23ba039..a73a5dc809 100644
--- a/test/SemaCXX/typo-correction-delayed.cpp
+++ b/test/SemaCXX/typo-correction-delayed.cpp
@@ -165,3 +165,13 @@ namespace PR22250 {
 // expected-error@+1 {{expected ';' after top level declarator}}
 int getenv_s(size_t *y, char(&z)) {}
 }
+
+namespace PR22297 {
+double pow(double x, double y);
+struct TimeTicks {
+  static void Now();  // expected-note {{'Now' declared here}}
+};
+void f() {
+  TimeTicks::now();  // expected-error {{no member named 'now' in 'PR22297::TimeTicks'; did you mean 'Now'?}}
+}
+}