TEST(FriendDecl, InstantiationSourceRange) {
RangeVerifier<FriendDecl> Verifier;
Verifier.expectRange(4, 3, 4, 35);
EXPECT_TRUE(Verifier.match(
"template <typename T> class S;\n"
"template<class T> void operator+(S<T> x);\n"
"template<class T> struct S {\n"
" friend void operator+<>(S<T> src);\n"
"};\n"
"void test(S<double> s) { +s; }",
friendDecl(hasParent(recordDecl(isTemplateInstantiation())))));
}
void DefinitionsInHeadersCheck::check(const MatchFinder::MatchResult &Result) {
// Don't run the check in failing TUs.
if (Result.Context->getDiagnostics().hasUncompilableErrorOccurred())
return;
// C++ [basic.def.odr] p6:
// There can be more than one definition of a class type, enumeration type,
// inline function with external linkage, class template, non-static function
// template, static data member of a class template, member function of a
// class template, or template specialization for which some template
// parameters are not specifiedin a program provided that each definition
// appears in a different translation unit, and provided the definitions
// satisfy the following requirements.
const auto *ND = Result.Nodes.getNodeAs<NamedDecl>("name-decl");
assert(ND);
if (ND->isInvalidDecl())
return;
// Internal linkage variable definitions are ignored for now:
// const int a = 1;
// static int b = 1;
//
// Although these might also cause ODR violations, we can be less certain and
// should try to keep the false-positive rate down.
//
// FIXME: Should declarations in anonymous namespaces get the same treatment
// as static / const declarations?
if (!ND->hasExternalFormalLinkage() && !ND->isInAnonymousNamespace())
return;
if (const auto *FD = dyn_cast<FunctionDecl>(ND)) {
// Inline functions are allowed.
if (FD->isInlined())
return;
// Function templates are allowed.
if (FD->getTemplatedKind() == FunctionDecl::TK_FunctionTemplate)
return;
// Ignore instantiated functions.
if (FD->isTemplateInstantiation())
return;
// Member function of a class template and member function of a nested class
// in a class template are allowed.
if (const auto *MD = dyn_cast<CXXMethodDecl>(FD)) {
const auto *DC = MD->getDeclContext();
while (DC->isRecord()) {
if (const auto *RD = dyn_cast<CXXRecordDecl>(DC)) {
if (isa<ClassTemplatePartialSpecializationDecl>(RD))
return;
if (RD->getDescribedClassTemplate())
return;
}
DC = DC->getParent();
}
}
bool is_full_spec = FD->getTemplateSpecializationKind() != TSK_Undeclared;
diag(FD->getLocation(),
"%select{function|full function template specialization}0 %1 defined "
"in a header file; function definitions in header files can lead to "
"ODR violations")
<< is_full_spec << FD << FixItHint::CreateInsertion(
FD->getReturnTypeSourceRange().getBegin(), "inline ");
} else if (const auto *VD = dyn_cast<VarDecl>(ND)) {
// Static data members of a class template are allowed.
if (VD->getDeclContext()->isDependentContext() && VD->isStaticDataMember())
return;
// Ignore instantiated static data members of classes.
if (isTemplateInstantiation(VD->getTemplateSpecializationKind()))
return;
// Ignore variable definition within function scope.
if (VD->hasLocalStorage() || VD->isStaticLocal())
return;
// Ignore inline variables.
if (VD->isInline())
return;
diag(VD->getLocation(),
"variable %0 defined in a header file; "
"variable definitions in header files can lead to ODR violations")
<< VD;
}
}
