Fix crash in redundant-void-arg check.

[angelgarcia]

Summary

When applying this check to the unit tests, it would hit an assertion:
llvm/tools/clang/lib/Lex/Lexer.cpp:1056: clang::SourceLocation clang::Lexer::getSourceLocation(const char*, unsigned int) const: Assertion `PP && "This doesn't work on raw lexers"' failed.

[alexfh]

clang-tidy/modernize/RedundantVoidArgCheck.cpp

132

What happens if instead you pass the range through Lexer::makeFileCharRange? This might be a way to enable fixes at least in some trivial cases involving macros.

[angelgarcia]

Use Lexer::makeFileCharRange (and a few changes due to clang-format).

It seems to work as well.

[alexfh]

In D14204#278833, @angelgarcia wrote:

Use Lexer::makeFileCharRange (and a few changes due to clang-format).

It seems to work as well.

Can you add a test where a void argument is removed in a macro (which would be the whole point of using the makeFileCharRange instead of just bailing out on all macros)?

E.g. does this work in a simple case like this one?

#define M(x) x
M(void f(void) {})
// CHECK-FIXES: M(void f() {})

[angelgarcia]

Sorry, I forgot. That case works just fine.

[alexfh]

Thanks! Looks good!

clang-tidy/modernize/RedundantVoidArgCheck.cpp

 
 } // namespace
 
 namespace tidy {
 namespace modernize {
 
 void RedundantVoidArgCheck::registerMatchers(MatchFinder *Finder) {
   Finder->addMatcher(functionDecl(isExpansionInMainFile(), parameterCountIs(0),
-                                  unless(isImplicit()),
-                                  unless(isExternC())).bind(FunctionId),
+                                  unless(isImplicit()), unless(isExternC()))
+                         .bind(FunctionId),
                      this);
   Finder->addMatcher(typedefDecl(isExpansionInMainFile()).bind(TypedefId),
                      this);
   auto ParenFunctionType = parenType(innerType(functionType()));
   auto PointerToFunctionType = pointee(ParenFunctionType);
   auto FunctionOrMemberPointer =
       anyOf(hasType(pointerType(PointerToFunctionType)),
             hasType(memberPointerType(PointerToFunctionType)));
void RedundantVoidArgCheck::registerMatchers(MatchFinder *Finder) {
   Finder->addMatcher(
       cxxStaticCastExpr(isExpansionInMainFile(), CastDestinationIsFunction)
           .bind(NamedCastId),
       this);
   Finder->addMatcher(
       cxxReinterpretCastExpr(isExpansionInMainFile(), CastDestinationIsFunction)
           .bind(NamedCastId),
       this);
-  Finder->addMatcher(cxxConstCastExpr(isExpansionInMainFile(),
-                                   CastDestinationIsFunction).bind(NamedCastId),
-                     this);
+  Finder->addMatcher(
+      cxxConstCastExpr(isExpansionInMainFile(), CastDestinationIsFunction)
+          .bind(NamedCastId),
   Finder->addMatcher(lambdaExpr(isExpansionInMainFile()).bind(LambdaId), this);
 }
 
 void RedundantVoidArgCheck::check(const MatchFinder::MatchResult &Result) {
   if (!Result.Context->getLangOpts().CPlusPlus) {
     return;
   }
 
if (Function->isThisDeclarationADefinition()) {
     removeVoidArgumentTokens(Result, Function->getSourceRange(),
                              "function declaration");
   }
 }
 
 void RedundantVoidArgCheck::removeVoidArgumentTokens(
     const ast_matchers::MatchFinder::MatchResult &Result, SourceRange Range,
     StringRef GrammarLocation) {
-  std::string DeclText =
-      Lexer::getSourceText(CharSourceRange::getTokenRange(Range),
-                           *Result.SourceManager,
-                           Result.Context->getLangOpts()).str();
-  Lexer PrototypeLexer(Range.getBegin(), Result.Context->getLangOpts(),
+  CharSourceRange CharRange = Lexer::makeFileCharRange(
+      CharSourceRange::getTokenRange(Range), *Result.SourceManager,
+      Result.Context->getLangOpts());
+
+  std::string DeclText = Lexer::getSourceText(CharRange, *Result.SourceManager,
+                                              Result.Context->getLangOpts())
+                             .str();
+  Lexer PrototypeLexer(CharRange.getBegin(), Result.Context->getLangOpts(),
                        DeclText.data(), DeclText.data(),
                        DeclText.data() + DeclText.size());
   enum TokenState {
     NothingYet,
     SawLeftParen,
     SawVoid,
   };
   TokenState State = NothingYet;

test/clang-tidy/modernize-redundant-void-arg.cpp

void test_lambda_functions() {
 
   auto gen3 = []{ return 1; };
 
   auto void_returner = [](void) -> void (*)(void) { return f1; };
   // CHECK-MESSAGES: [[@LINE-1]]:27: warning: {{.*}} in lambda expression
   // CHECK-MESSAGES: [[@LINE-2]]:45: warning: {{.*}} in lambda expression
   // CHECK-FIXES: {{^  }}auto void_returner = []() -> void (*)() { return f1; };{{$}}
 }
+
+#define M(x) x
+
+M(void inmacro(void) {})
+// CHECK-MESSAGES: :[[@LINE-1]]:16: warning: {{.*}} in function definition
+// CHECK-FIXES: M(void inmacro() {})
+
+#define F(A, B)        \
+  struct F_##A##_##B { \
+    F_##A##_##B(void); \
+  };                   \
+  F_##A##_##B::F_##A##_##B(void)
+
+F(Foo, Bar) {
+
+}