[clang] a642eb8 - [Clang][Sema] Fix crash when using name of UnresolvedUsingValueDecl with template arguments (#83842)
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cfe-commits at lists.llvm.org
Tue Mar 5 05:52:24 PST 2024
Author: Krystian Stasiowski
Date: 2024-03-05T08:52:20-05:00
New Revision: a642eb89bdaf10c6b4994fc1187de27b441236ed
URL: https://github.com/llvm/llvm-project/commit/a642eb89bdaf10c6b4994fc1187de27b441236ed
DIFF: https://github.com/llvm/llvm-project/commit/a642eb89bdaf10c6b4994fc1187de27b441236ed.diff
LOG: [Clang][Sema] Fix crash when using name of UnresolvedUsingValueDecl with template arguments (#83842)
The following snippet causes a crash:
```
template<typename T>
struct A : T {
using T::f;
void f();
void g() {
f<int>(); // crash here
}
};
```
This happens because we cast the result of `getAsTemplateNameDecl` as a
`TemplateDecl` in `Sema::ClassifyName`, which we cannot do for an
`UnresolvedUsingValueDecl`. This patch fixes the crash by considering a name
to be that of a template if _any_ function declaration is found per [temp.names] p3.3.
Added:
clang/test/SemaTemplate/unqual-unresolved-using-value.cpp
Modified:
clang/docs/ReleaseNotes.rst
clang/lib/Sema/SemaDecl.cpp
clang/lib/Sema/SemaTemplate.cpp
Removed:
################################################################################
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index c328ae18c024ce..de5f339cc7f0ba 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -305,6 +305,8 @@ Bug Fixes to C++ Support
our attention by an attempt to fix in (#GH77703). Fixes (#GH83385).
- Fix evaluation of some immediate calls in default arguments.
Fixes (#GH80630)
+- Fix a crash when an explicit template argument list is used with a name for which lookup
+ finds a non-template function and a dependent using declarator.
Bug Fixes to AST Handling
^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 3ae78748a4e499..8fcaf6ab312b04 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -1110,7 +1110,9 @@ Sema::NameClassification Sema::ClassifyName(Scope *S, CXXScopeSpec &SS,
// unqualified-id followed by a < and name lookup finds either one
// or more functions or finds nothing.
if (!IsFilteredTemplateName)
- FilterAcceptableTemplateNames(Result);
+ FilterAcceptableTemplateNames(Result,
+ /*AllowFunctionTemplates=*/true,
+ /*AllowDependent=*/true);
bool IsFunctionTemplate;
bool IsVarTemplate;
@@ -1120,6 +1122,7 @@ Sema::NameClassification Sema::ClassifyName(Scope *S, CXXScopeSpec &SS,
Template = Context.getOverloadedTemplateName(Result.begin(),
Result.end());
} else if (!Result.empty()) {
+ assert(!Result.isUnresolvableResult());
auto *TD = cast<TemplateDecl>(getAsTemplateNameDecl(
*Result.begin(), /*AllowFunctionTemplates=*/true,
/*AllowDependent=*/false));
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 873ea10ebe0660..df20f83ac8afe6 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -491,18 +491,20 @@ bool Sema::LookupTemplateName(LookupResult &Found,
// To keep our behavior consistent, we apply the "finds nothing" part in
// all language modes, and diagnose the empty lookup in ActOnCallExpr if we
// successfully form a call to an undeclared template-id.
- bool AllFunctions =
- getLangOpts().CPlusPlus20 && llvm::all_of(Found, [](NamedDecl *ND) {
+ bool AnyFunctions =
+ getLangOpts().CPlusPlus20 && llvm::any_of(Found, [](NamedDecl *ND) {
return isa<FunctionDecl>(ND->getUnderlyingDecl());
});
- if (AllFunctions || (Found.empty() && !IsDependent)) {
+ if (AnyFunctions || (Found.empty() && !IsDependent)) {
// If lookup found any functions, or if this is a name that can only be
// used for a function, then strongly assume this is a function
// template-id.
*ATK = (Found.empty() && Found.getLookupName().isIdentifier())
? AssumedTemplateKind::FoundNothing
: AssumedTemplateKind::FoundFunctions;
- Found.clear();
+ FilterAcceptableTemplateNames(Found,
+ /*AllowFunctionTemplates*/ true,
+ /*AllowDependent*/ true);
return false;
}
}
diff --git a/clang/test/SemaTemplate/unqual-unresolved-using-value.cpp b/clang/test/SemaTemplate/unqual-unresolved-using-value.cpp
new file mode 100644
index 00000000000000..688e7a0a10b779
--- /dev/null
+++ b/clang/test/SemaTemplate/unqual-unresolved-using-value.cpp
@@ -0,0 +1,30 @@
+// RUN: %clang_cc1 -std=c++20 -fsyntax-only -verify %s
+
+template<typename T>
+struct A : T {
+ using T::f;
+ using T::g;
+ using T::h;
+
+ void f();
+ void g();
+
+ void i() {
+ f<int>();
+ g<int>(); // expected-error{{no member named 'g' in 'A<B>'}}
+ h<int>(); // expected-error{{expected '(' for function-style cast or type construction}}
+ // expected-error at -1{{expected expression}}
+ }
+};
+
+struct B {
+ template<typename T>
+ void f();
+
+ void g();
+
+ template<typename T>
+ void h();
+};
+
+template struct A<B>; // expected-note{{in instantiation of member function 'A<B>::i' requested here}}
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