[PATCH] D60848: [Parser] Avoid correcting delayed typos in array subscript multiple times.

[Volodymyr Sapsai via Phabricator via cfe-commits]

vsapsai created this revision.
vsapsai added reviewers: rsmith, erik.pilkington, majnemer.
Herald added subscribers: dexonsmith, jkorous.

We correct some typos in `ActOnArraySubscriptExpr` and
`ActOnOMPArraySectionExpr`, so when their result is `ExprError`, we can
end up correcting delayed typos in the same expressions again. In
general it is OK but when `NumTypos` is incorrect, we can hit the
assertion

> Assertion failed: (Entry != DelayedTypos.end() && "Failed to get the state for a TypoExpr!"), function getTypoExprState, file clang/lib/Sema/SemaLookup.cpp, line 5219.

This assertion is reproducible with Objective-C method

- (void)test { [self undeclaredMethod:undeclaredArg]; NSMutableDictionary *opts = [NSMutableDictionary new]; opts[(__bridge id)undeclaredKey] = @0; }

There is no test for the fix because `NumTypos` is still incorrect and
we hit the assertion

> Assertion failed: (DelayedTypos.empty() && "Uncorrected typos!"), function ~Sema, file clang/lib/Sema/Sema.cpp, line 382.

Another option is to fix tracking delayed typos but it is non-trivial as
in many cases we drop erroneous expressions without cleaning up
`TypoExpr` they contain. Also the assertion in `~Sema` isn't causing
problems with assertions disabled, while a missing `TypoExprState` can
cause a segmentation fault.

rdar://problem/47403222


https://reviews.llvm.org/D60848

Files:
  clang/lib/Parse/ParseExpr.cpp
  clang/test/SemaCXX/typo-correction.cpp


Index: clang/test/SemaCXX/typo-correction.cpp
===================================================================
--- clang/test/SemaCXX/typo-correction.cpp
+++ clang/test/SemaCXX/typo-correction.cpp
@@ -678,7 +678,7 @@
 struct a0is0 {};
 struct b0is0 {};
 int g() {
-  0 [                 // expected-error {{subscripted value is not an array}}
+  0 [
       sizeof(c0is0)]; // expected-error {{use of undeclared identifier}}
 };
 }
Index: clang/lib/Parse/ParseExpr.cpp
===================================================================
--- clang/lib/Parse/ParseExpr.cpp
+++ clang/lib/Parse/ParseExpr.cpp
@@ -1582,7 +1582,9 @@
 
       SourceLocation RLoc = Tok.getLocation();
 
-      ExprResult OrigLHS = LHS;
+      LHS = Actions.CorrectDelayedTyposInExpr(LHS);
+      Idx = Actions.CorrectDelayedTyposInExpr(Idx);
+      Length = Actions.CorrectDelayedTyposInExpr(Length);
       if (!LHS.isInvalid() && !Idx.isInvalid() && !Length.isInvalid() &&
           Tok.is(tok::r_square)) {
         if (ColonLoc.isValid()) {
@@ -1594,12 +1596,6 @@
         }
       } else {
         LHS = ExprError();
-      }
-      if (LHS.isInvalid()) {
-        (void)Actions.CorrectDelayedTyposInExpr(OrigLHS);
-        (void)Actions.CorrectDelayedTyposInExpr(Idx);
-        (void)Actions.CorrectDelayedTyposInExpr(Length);
-        LHS = ExprError();
         Idx = ExprError();
       }
 


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