[Sema] Fix infinite typo correction loop.

NumTypos guard value ~0U doesn't prevent from creating new delayed typos. When
you create new delayed typos during typo correction, value ~0U wraps around to
0. When NumTypos is 0 we can miss some typos and treat an expression as it can
be typo-corrected. But if the expression is still invalid after correction, we
can get stuck in infinite loop trying to correct it.

Fix by not using value ~0U so that NumTypos correctly reflects the number of
typos.

rdar://problem/38642201

Reviewers: arphaman, majnemer, rsmith

Reviewed By: rsmith

Subscribers: rsmith, nicholas, cfe-commits

Differential Revision: https://reviews.llvm.org/D47341

llvm-svn: 335638

1 files changed, 13 insertions, 0 deletions

diff --git a/clang/test/Sema/typo-correction.c b/clang/test/Sema/typo-correction.c
index 78007015dca..e7992ac90bb 100644
--- a/clang/test/Sema/typo-correction.c
+++ b/clang/test/Sema/typo-correction.c
@@ -87,3 +87,16 @@ __attribute__((overloadable)) void func_overloadable(float);
 void overloadable_callexpr(int arg) {
 	func_overloadable(ar); //expected-error{{use of undeclared identifier}}
 }
+
+// rdar://problem/38642201
+struct rdar38642201 {
+  int fieldName;
+};
+
+void rdar38642201_callee(int x, int y);
+void rdar38642201_caller() {
+  struct rdar38642201 structVar;
+  rdar38642201_callee(
+      structVar1.fieldName1.member1, //expected-error{{use of undeclared identifier 'structVar1'}}
+      structVar2.fieldName2.member2); //expected-error{{use of undeclared identifier 'structVar2'}}
+}