[clang-tidy] Fix bugprone-terminating-continue when continue appears inside a switch

[njames93]

Summary

Don't emit a warning if the continue appears in a switch context as changing it to break will break out of the switch rather than a do loop containing the switch.
Fixes https://llvm.org/PR49492.

[aaron.ballman]

LGTM, but please commit with a better commit message.

clang-tools-extra/test/clang-tidy/checkers/bugprone-terminating-continue.cpp

81

I'd appreciate an additional test:

switch (2) {
case 2: do {
  continue; // Should still diagnose this one
} while (0);
}

[njames93]

Add test case for do inside switch.

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

 void TerminatingContinueCheck::registerMatchers(MatchFinder *Finder) {
   const auto DoWithFalse =
       doStmt(hasCondition(ignoringImpCasts(
                  anyOf(cxxBoolLiteral(equals(false)), integerLiteral(equals(0)),
                        cxxNullPtrLiteralExpr(), gnuNullExpr()))),
              equalsBoundNode("closestLoop"));
 
   Finder->addMatcher(
-      continueStmt(hasAncestor(stmt(anyOf(forStmt(), whileStmt(),
-                                          cxxForRangeStmt(), doStmt()))
-                                   .bind("closestLoop")),
-                   hasAncestor(DoWithFalse))
+      continueStmt(
+          hasAncestor(stmt(anyOf(forStmt(), whileStmt(), cxxForRangeStmt(),
+                                 doStmt(), switchStmt()))
           .bind("continue"),
       this);
 }
 
 void TerminatingContinueCheck::check(const MatchFinder::MatchResult &Result) {
   const auto *ContStmt = Result.Nodes.getNodeAs<ContinueStmt>("continue");
 
   auto Diag =
       diag(ContStmt->getBeginLoc(),
            "'continue' in loop with false condition is equivalent to 'break'")
       << tooling::fixit::createReplacement(*ContStmt, "break");
 }
 
 } // namespace bugprone
 } // namespace tidy
 } // namespace clang

clang-tools-extra/test/clang-tidy/checkers/bugprone-terminating-continue.cpp

void f() {
 
 
   do {
     int x = 1;
     if (x > 0) continue;
     // CHECK-MESSAGES: :[[@LINE-1]]:16: warning: 'continue' in loop with false condition is equivalent to 'break' [bugprone-terminating-continue]
     // CHECK-FIXES: if (x > 0) break;
   } while (false);
+
+  switch (2) {
+  case 2:
+    do {
+      continue; // LoopInSwitch
+      // CHECK-MESSAGES: :[[@LINE-1]]:7: warning: 'continue' in loop with false condition is equivalent to 'break' [bugprone-terminating-continue]
+      // CHECK-FIXES: break; // LoopInSwitch
+    } while (0);
+  }
 }
 
 void g() {
   do {
     do {
       continue;
       int x = 1;
     } while (1 == 1);
void g() {
   } while (false);
 
   int v[] = {1,2,3,34};
   do {
     for (int n : v) {
       if (n>2) continue;
     }
   } while (false);
+
+  do {
+    switch (2) {
+    case 1:
+    case 2:
+      continue;
+    }
+  } while (false);
 }