r259820 - Fix a crash when there is a typo in the return statement.

[Manman Ren via cfe-commits]

Author: mren
Date: Thu Feb  4 14:05:40 2016
New Revision: 259820

URL: http://llvm.org/viewvc/llvm-project?rev=259820&view=rev
Log:
Fix a crash when there is a typo in the return statement.

If the typo happens after a successful deduction for an earlier
return statement, we should check if the deduced type is null
before using it.

The typo correction happens after we try to deduce the return
type and we ignore the deduction from the typo and continue
to typo correction.

rdar://24342247

Added:
    cfe/trunk/test/SemaCXX/typo-correction-crash.cpp
Modified:
    cfe/trunk/lib/Sema/SemaStmt.cpp

Modified: cfe/trunk/lib/Sema/SemaStmt.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaStmt.cpp?rev=259820&r1=259819&r2=259820&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaStmt.cpp (original)
+++ cfe/trunk/lib/Sema/SemaStmt.cpp Thu Feb  4 14:05:40 2016
@@ -3069,6 +3069,11 @@ bool Sema::DeduceFunctionTypeFromReturnE
   QualType DeducedT = AT->getDeducedType();
   if (!DeducedT.isNull() && !FD->isInvalidDecl()) {
     AutoType *NewAT = Deduced->getContainedAutoType();
+    // It is possible that NewAT->getDeducedType() is null. When that happens,
+    // we should not crash, instead we ignore this deduction.
+    if (NewAT->getDeducedType().isNull())
+      return false;
+
     CanQualType OldDeducedType = Context.getCanonicalFunctionResultType(
                                    DeducedT);
     CanQualType NewDeducedType = Context.getCanonicalFunctionResultType(

Added: cfe/trunk/test/SemaCXX/typo-correction-crash.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/typo-correction-crash.cpp?rev=259820&view=auto
==============================================================================
--- cfe/trunk/test/SemaCXX/typo-correction-crash.cpp (added)
+++ cfe/trunk/test/SemaCXX/typo-correction-crash.cpp Thu Feb  4 14:05:40 2016
@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -fsyntax-only -std=c++14 -verify %s
+auto check1() {
+  return 1;
+  return s; // expected-error {{use of undeclared identifier 's'}}
+}
+
+int test = 11; // expected-note {{'test' declared here}}
+auto check2() {
+  return "s";
+  return tes; // expected-error {{use of undeclared identifier 'tes'; did you mean 'test'?}}
+}