[NFC] [clang-tidy] Fix potential SA issues.

clang-tools-extra/clang-tidy/ExpandModularHeadersPPCallbacks.h

@@ -137,7 +137,7 @@ class ExpandModularHeadersPPCallbacks : public PPCallbacks {
   std::unique_ptr<Preprocessor> PP;
   bool EnteredMainFile = false;
   bool StartedLexing = false;
-  Token CurrentToken;
+  Token CurrentToken = Token();
 };
 
 } // namespace tooling

clang-tools-extra/clang-tidy/bugprone/FloatLoopCounterCheck.cpp

@@ -31,6 +31,7 @@ void FloatLoopCounterCheck::registerMatchers(MatchFinder *Finder) {
 
 void FloatLoopCounterCheck::check(const MatchFinder::MatchResult &Result) {
   const auto *FS = Result.Nodes.getNodeAs<ForStmt>("for");
+  if (!FS) return; // Check if FS is null and exit if it is.
 
   diag(FS->getInc()->getBeginLoc(), "loop induction expression should not have "
                                     "floating-point type")

clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsAvoidUncheckedContainerAccessCheck.cpp

@@ -179,6 +179,12 @@ void ProBoundsAvoidUncheckedContainerAccessCheck::check(
     // Case: a.operator[](i) or a->operator[](i)
     const auto *Callee = dyn_cast<MemberExpr>(MCE->getCallee());
 
+    if (!Callee) {
+      diag(MatchedExpr->getCallee()->getBeginLoc(), "invalid member expression")
+          << MatchedExpr->getCallee()->getSourceRange();
+      return;
+    }
+
     if (FixMode == At) {
       // Cases: a.operator[](i) => a.at(i) and a->operator[](i) => a->at(i)