riccibruno updated this revision to Diff 284364.
riccibruno marked 2 inline comments as done.
riccibruno edited the summary of this revision.
riccibruno added a comment.
Refer to the binding in the diagnostic.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D85613/new/
https://reviews.llvm.org/D85613
Files:
clang/include/clang/AST/DeclCXX.h
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/lib/Sema/SemaDeclCXX.cpp
clang/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p7.cpp
Index: clang/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p7.cpp
===================================================================
--- clang/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p7.cpp
+++ clang/test/CXX/dcl.decl/dcl.meaning/dcl.fct.default/p7.cpp
@@ -1,5 +1,20 @@
// RUN: %clang_cc1 -std=c++17 -fsyntax-only -verify %s
+namespace std {
+using size_t = decltype(sizeof(int));
+template <typename> struct tuple_size;
+template <size_t, typename> struct tuple_element;
+} // namespace std
+using size_t = std::size_t;
+
+struct E {};
+template <size_t> int get(E);
+
+namespace std {
+template <> struct tuple_size<E> { static constexpr size_t value = 2; };
+template <size_t I> struct tuple_element<I, E> { using type = int; };
+}; // namespace std
+
void h() {
int i1 = 0;
extern void h1(int x = i1);
@@ -22,10 +37,21 @@
};
extern void h6(int = i5);
- // expected-error-re@-1 {{default argument references local variable '(unnamed variable of type (anonymous union at {{.*}}:20:3))' of enclosing function}}
+ // expected-error-re@-1 {{default argument references local variable '(unnamed variable of type (anonymous union at {{.*}}:35:3))' of enclosing function}}
+
+ struct S {
+ int i, j;
+ };
+ auto [x, y] = S();
+
+ extern void h7(int = x); // expected-error {{default argument references local binding 'x'}}
- struct S { int i; };
- auto [x] = S();
+ auto [z, w] = E();
+ extern void h8a(int = sizeof(z)); // ok
+ extern void h8b(int = w); // expected-error {{default argument references local binding 'w'}}
- extern void h7(int = x); // FIXME: reject
+ extern auto get_array()->int(&)[2];
+ auto [a0, a1] = get_array();
+ extern void h9a(int = sizeof(a0));
+ extern void h9b(int = a1); // expected-error {{default argument references local binding 'a1'}}
}
Index: clang/lib/Sema/SemaDeclCXX.cpp
===================================================================
--- clang/lib/Sema/SemaDeclCXX.cpp
+++ clang/lib/Sema/SemaDeclCXX.cpp
@@ -86,6 +86,22 @@
/// argument expression.
bool CheckDefaultArgumentVisitor::VisitDeclRefExpr(const DeclRefExpr *DRE) {
const NamedDecl *Decl = DRE->getDecl();
+
+ auto CheckAndDiagnoseLocalEntity = [&](const VarDecl *VD, unsigned DiagID,
+ const auto &... DiagArgs) -> bool {
+ if (VD->isLocalVarDecl() && !DRE->isNonOdrUse()) {
+ auto DB = S.Diag(DRE->getBeginLoc(), DiagID);
+ // FIXME: Replace with a fold once we can use C++17.
+ int dummy[] = {(DB << DiagArgs, 0)...};
+ (void)dummy;
+
+ DB << DefaultArg->getSourceRange();
+ return true;
+ }
+
+ return false;
+ };
+
if (const auto *Param = dyn_cast<ParmVarDecl>(Decl)) {
// C++ [dcl.fct.default]p9:
// [...] parameters of a function shall not be used in default
@@ -111,10 +127,28 @@
// C++20 [dcl.fct.default]p7 (DR as part of P0588R1, see also CWG 2346):
// Note: A local variable cannot be odr-used (6.3) in a default argument.
//
- if (VDecl->isLocalVarDecl() && !DRE->isNonOdrUse())
- return S.Diag(DRE->getBeginLoc(),
- diag::err_param_default_argument_references_local)
- << VDecl << DefaultArg->getSourceRange();
+ if (CheckAndDiagnoseLocalEntity(
+ VDecl, diag::err_param_default_argument_references_local,
+ /*variable*/ 0, VDecl))
+ return true;
+
+ } else if (const auto *Binding = dyn_cast<BindingDecl>(Decl)) {
+ // C++20 [basic.pre]p7:
+ // A local entity is [...] a structured binding whose corresponding
+ // variable is such an entity [...]
+ //
+ // C++20 [basic.def.odr]p9:
+ // A local entity (6.1) is odr-usable in a declarative region if [...]
+ //
+ // Note that this was not entirely clear in C++17 since [dcl.fct.default]p7
+ // only prohibited local variables (a structured binding declaration
+ // introduces identifiers as names).
+ //
+ const auto *VD = cast_or_null<VarDecl>(Binding->getDecomposedDecl());
+ if (VD && CheckAndDiagnoseLocalEntity(
+ VD, diag::err_param_default_argument_references_local,
+ /*binding*/ 1, Binding))
+ return true;
}
return false;
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3988,7 +3988,8 @@
def err_param_default_argument_references_param : Error<
"default argument references parameter %0">;
def err_param_default_argument_references_local : Error<
- "default argument references local variable %0 of enclosing function">;
+ "default argument references local %select{variable|binding}0 %1 "
+ "of enclosing function">;
def err_param_default_argument_references_this : Error<
"default argument references 'this'">;
def err_param_default_argument_nonfunc : Error<
Index: clang/include/clang/AST/DeclCXX.h
===================================================================
--- clang/include/clang/AST/DeclCXX.h
+++ clang/include/clang/AST/DeclCXX.h
@@ -3840,6 +3840,8 @@
/// DecompositionDecl of type 'int (&)[3]'.
class BindingDecl : public ValueDecl {
/// The declaration that this binding binds to part of.
+ // FIXME: Currently not set during deserialization of the BindingDecl;
+ // only set when the corresponding DecompositionDecl is visited.
LazyDeclPtr Decomp;
/// The binding represented by this declaration. References to this
/// declaration are effectively equivalent to this expression (except
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
