Merge pull request checkedc#1196 from Arunkumar1998BOM/main

Fix for Issue checkedc#1195 

Reason for the error:

typename llvm::cast_retty<X, Y*>::ret_type llvm::cast(Y*) [with X = clang::Expr; Y = const clang::Stmt; typename llvm::cast_retty<X, Y*>::ret_type = const clang::Expr*] caused an assertion:

Assertion `isa<X>(Val) && "cast<Ty>() argument of incompatible type!"' failed.

Description of Fix:
I have a fix I believe involves the least changes, so as to disturb the main line as little as possible.

Regression CheckedC Testing:

Testing Time: 14.53s
  Unsupported:  3
  Passed     : 96

Regression testing:

Ran clang tests:
Failed Tests (3):
  Clang :: 3C/json_formatting.c
  Clang :: 3C/json_formatting_backslash.c
  Clang :: 3C/multiple_tu.c


Testing Time: 2095.93s
  Unsupported      :    75
  Passed           : 27663
  Expectedly Failed:    34
  Failed           :     3


The above 3 tests also failed for me on an "untouched" main-branch.

clang/lib/Analysis/CFG.cpp

@@ -5965,6 +5965,10 @@ const Expr *CFGBlock::getLastCondition() const {
   if (isa<ObjCForCollectionStmt>(Cond) || isa<DeclStmt>(Cond))
     return nullptr;
 
+  // Introduced as a fix for crash --> #1195
+  if (!isa<Expr>(Cond))
+    return nullptr;
+
   // Only ObjCForCollectionStmt is known not to be a non-Expr terminator, hence
   // the cast<>.
   return cast<Expr>(Cond)->IgnoreParens();