[PATCH] D69060: [Sema][Typo Correction] Fix another infinite loop on ambiguity

[David Goldman via Phabricator via cfe-commits]

dgoldman created this revision.
dgoldman added a reviewer: rsmith.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.

See also: D67515 <https://reviews.llvm.org/D67515>

- For the given call expression we would end up repeatedly trying to transform the same expression over and over again

- Fix is to keep the old TransformCache when checking for ambiguity


Repository:
  rC Clang

https://reviews.llvm.org/D69060

Files:
  lib/Sema/SemaExprCXX.cpp
  test/Sema/typo-correction-ambiguity.c


Index: test/Sema/typo-correction-ambiguity.c
===================================================================
--- /dev/null
+++ test/Sema/typo-correction-ambiguity.c
@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+// Check the following typo correction behavior in C:
+// - no typos are diagnosed when a call expression has ambiguous (multiple) corrections
+
+int v_63;
+
+void v_2_0(int v_452, int v_454) {}
+
+int v_3_0() {
+   for (int v_345 = 0 ; v_63;)
+       v_2_0(v_195,  // expected-error {{use of undeclared identifier 'v_195'}}
+             v_231);  // expected-error {{use of undeclared identifier 'v_231'}}
+}
Index: lib/Sema/SemaExprCXX.cpp
===================================================================
--- lib/Sema/SemaExprCXX.cpp
+++ lib/Sema/SemaExprCXX.cpp
@@ -7779,8 +7779,8 @@
 
     // If we found a valid result, double check to make sure it's not ambiguous.
     if (!IsAmbiguous && !Res.isInvalid() && !AmbiguousTypoExprs.empty()) {
-      auto SavedTransformCache = std::move(TransformCache);
-      TransformCache.clear();
+      auto SavedTransformCache = llvm::SmallDenseMap<TypoExpr *, ExprResult, 2>(TransformCache);
+
       // Ensure none of the TypoExprs have multiple typo correction candidates
       // with the same edit length that pass all the checks and filters.
       while (!AmbiguousTypoExprs.empty()) {


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