https://github.com/cor3ntin created
https://github.com/llvm/llvm-project/pull/138731
When forming an invalid function type, we were not diagnosing it if the call
was dependent.
However, we later rely on the function type to be sensible during argument
deduction.
We now diagnose anything that is not a potential function type, to avoid
constructing bogus call expressions.
Fixes #138657
Fixes #115725
Fixes #68852
>From 6e17e8e048a3b75d08d17d4e30eb0daed447ab98 Mon Sep 17 00:00:00 2001
From: Corentin Jabot <corentinja...@gmail.com>
Date: Tue, 6 May 2025 20:00:18 +0200
Subject: [PATCH] [Clang] Diagnose invalid function types in dependent contexts
When forming an invalid function type, we were not diagnosing
it if the call was dependent.
However, we later rely on the function type to be sensible
during argument deduction.
We now diagnose anything that is not a potential function type,
to avoid constructing bogus call expressions.
Fixes #138657
Fixes #115725
Fixes #68852
---
clang/docs/ReleaseNotes.rst | 1 +
clang/lib/Sema/SemaExpr.cpp | 19 ++++++++
clang/test/SemaTemplate/fun-template-def.cpp | 51 +++++++++++++++++++-
3 files changed, 70 insertions(+), 1 deletion(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 203958dab7430..bdd54f6a52b05 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -655,6 +655,7 @@ Bug Fixes to C++ Support
- Fixed an assertion when trying to constant-fold various builtins when the
argument
referred to a reference to an incomplete type. (#GH129397)
- Fixed a crash when a cast involved a parenthesized aggregate initialization
in dependent context. (#GH72880)
+- Fixed a crash when forming an invalid function type in a dependent context.
(#GH138657) (#GH115725) (#GH68852)
Bug Fixes to AST Handling
^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index be3f145f3c5f1..f463bffa83545 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -6541,6 +6541,15 @@ ExprResult Sema::ActOnCallExpr(Scope *Scope, Expr *Fn,
SourceLocation LParenLoc,
return Call;
}
+// Any type that could be used to form a callable expression
+static bool MayBeFunctionType(const ASTContext &Context, QualType T) {
+ return T == Context.BoundMemberTy || T == Context.UnknownAnyTy ||
+ T == Context.BuiltinFnTy || T == Context.OverloadTy ||
+ T->isFunctionType() || T->isFunctionReferenceType() ||
+ T->isMemberFunctionPointerType() || T->isFunctionPointerType() ||
+ T->isBlockPointerType() || T->isRecordType();
+}
+
ExprResult Sema::BuildCallExpr(Scope *Scope, Expr *Fn, SourceLocation
LParenLoc,
MultiExprArg ArgExprs, SourceLocation RParenLoc,
Expr *ExecConfig, bool IsExecConfig,
@@ -6594,6 +6603,16 @@ ExprResult Sema::BuildCallExpr(Scope *Scope, Expr *Fn,
SourceLocation LParenLoc,
*this, dyn_cast<UnresolvedMemberExpr>(Fn->IgnoreParens()),
Fn->getBeginLoc());
+ if (!Fn->getType()->isDependentType()) {
+ // If the type of the function itself is not dependent
+ // check that it is a reasonable as a function, as type deduction
+ // later assume the CallExpr has a sensible TYPE.
+ if (!MayBeFunctionType(Context, Fn->getType()))
+ return ExprError(
+ Diag(LParenLoc, diag::err_typecheck_call_not_function)
+ << Fn->getType() << Fn->getSourceRange());
+ }
+
return CallExpr::Create(Context, Fn, ArgExprs, Context.DependentTy,
VK_PRValue, RParenLoc,
CurFPFeatureOverrides());
}
diff --git a/clang/test/SemaTemplate/fun-template-def.cpp
b/clang/test/SemaTemplate/fun-template-def.cpp
index de77901b5b601..716296e72bc44 100644
--- a/clang/test/SemaTemplate/fun-template-def.cpp
+++ b/clang/test/SemaTemplate/fun-template-def.cpp
@@ -1,6 +1,7 @@
// RUN: %clang_cc1 -fsyntax-only -verify %s
// RUN: %clang_cc1 -fsyntax-only -verify -std=c++98 %s
// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++20 %s
// Tests that dependent expressions are always allowed, whereas non-dependent
// are checked as usual.
@@ -32,7 +33,7 @@ T f1(T t1, U u1, int i1, T** tpp)
i1 = t1[u1];
i1 *= t1;
- i1(u1, t1); // error
+ i1(u1, t1); // expected-error {{called object type 'int' is not a function
or function pointer}}
u1(i1, t1);
U u2 = (T)i1;
@@ -60,3 +61,51 @@ void f3() {
f2<int*>(0);
f2<int>(0); // expected-error {{no matching function for call to 'f2'}}
}
+
+#if __cplusplus >= 202002L
+namespace GH138657 {
+template <auto V> // #gh138657-template-head
+class meta {};
+template<int N>
+class meta<N()> {}; // expected-error {{called object type 'int' is not a
function or function point}}
+
+template<int N[1]>
+class meta<N()> {}; // expected-error {{called object type 'int *' is not a
function or function point}}
+
+template<char* N>
+class meta<N()> {}; // expected-error {{called object type 'char *' is not a
function or function point}}
+
+struct S {};
+template<S>
+class meta<S()> {}; // expected-error {{template argument for non-type
template parameter is treated as function type 'S ()'}}
+ // expected-note@#gh138657-template-head {{template
parameter is declared here}}
+
+}
+
+namespace GH115725 {
+template<auto ...> struct X {};
+template<typename T, typename ...Ts> struct A {
+ template<Ts ...Ns, T *...Ps>
+ A(X<0(Ps)...>, Ts (*...qs)[Ns]);
+ // expected-error@-1{{called object type 'int' is not a function or function
pointer}}
+
+};
+}
+
+namespace GH68852 {
+template <auto v>
+struct constexpr_value {
+ template <class... Ts>
+ constexpr constexpr_value<v(Ts::value...)> call(Ts...) {
+ //expected-error@-1 {{called object type 'int' is not a function or
function pointer}}
+ return {};
+ }
+};
+
+template <auto v> constexpr static inline auto c_ = constexpr_value<v>{};
+// expected-note@-1 {{in instantiation of template}}
+auto k = c_<1>; // expected-note {{in instantiation of variable}}
+
+}
+
+#endif
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