https://github.com/0x59616e updated
https://github.com/llvm/llvm-project/pull/65193:
>From 3eafb85ff74271456cba24ea5892dd5660c1d332 Mon Sep 17 00:00:00 2001
From: Sheng <ox596...@gmail.com>
Date: Wed, 30 Aug 2023 11:44:23 +0800
Subject: [PATCH] [clang][Sema] Fix a bug when instantiating a lambda with
requires clause
Instantiating a lambda at a scope different from its definition
scope will paralyze clang if the trailing require clause
refers to local variables of that definition scope.
This patch fixes this by re-adding the local variables to
`LocalInstantiationScope`.
Fixes #64462
---
clang/lib/Sema/SemaConcept.cpp | 59 ++++++++++++++++++++++++++++++++++
clang/test/SemaCXX/pr64462.cpp | 20 ++++++++++++
2 files changed, 79 insertions(+)
create mode 100644 clang/test/SemaCXX/pr64462.cpp
diff --git a/clang/lib/Sema/SemaConcept.cpp b/clang/lib/Sema/SemaConcept.cpp
index d1fa8e7831225b7..e48e0f743927a17 100644
--- a/clang/lib/Sema/SemaConcept.cpp
+++ b/clang/lib/Sema/SemaConcept.cpp
@@ -567,6 +567,58 @@ bool Sema::addInstantiatedCapturesToScope(
return false;
}
+static void addDeclsFromParentScope(Sema &S, FunctionDecl *FD,
+ LocalInstantiationScope &Scope) {
+ assert(isLambdaCallOperator(FD) && "FD must be a lambda call operator");
+
+ LambdaScopeInfo *LSI = cast<LambdaScopeInfo>(S.getFunctionScopes().back());
+
+ auto captureVar = [&](VarDecl *VD) {
+ LSI->addCapture(VD, /*isBlock=*/false, /*isByref=*/false,
+ /*isNested=*/false, VD->getBeginLoc(), SourceLocation(),
+ VD->getType(), /*Invalid=*/false);
+ };
+
+ FD = dyn_cast<FunctionDecl>(FD->getParent()->getParent());
+
+ if (!FD || !FD->isTemplateInstantiation())
+ return;
+
+ FunctionDecl *Pattern = FD->getPrimaryTemplate()->getTemplatedDecl();
+
+ for (unsigned I = 0; I < Pattern->getNumParams(); ++I) {
+ ParmVarDecl *PVD = Pattern->getParamDecl(I);
+ if (!PVD->isParameterPack()) {
+ Scope.InstantiatedLocal(PVD, FD->getParamDecl(I));
+ captureVar(FD->getParamDecl(I));
+ continue;
+ }
+
+ Scope.MakeInstantiatedLocalArgPack(PVD);
+
+ for (ParmVarDecl *Inst : FD->parameters().drop_front(I)) {
+ Scope.InstantiatedLocalPackArg(PVD, Inst);
+ captureVar(Inst);
+ }
+ }
+
+ for (auto *decl : Pattern->decls()) {
+ if (!isa<VarDecl>(decl) || isa<ParmVarDecl>(decl))
+ continue;
+
+ IdentifierInfo *II = cast<NamedDecl>(decl)->getIdentifier();
+ auto it = llvm::find_if(FD->decls(), [&](Decl *inst) {
+ VarDecl *VD = dyn_cast<VarDecl>(inst);
+ return VD && VD->isLocalVarDecl() && VD->getIdentifier() == II;
+ });
+
+ assert(it != FD->decls().end() && "Cannot find the instantiated
variable.");
+
+ Scope.InstantiatedLocal(decl, *it);
+ captureVar(cast<VarDecl>(*it));
+ }
+}
+
bool Sema::SetupConstraintScope(
FunctionDecl *FD, std::optional<ArrayRef<TemplateArgument>> TemplateArgs,
MultiLevelTemplateArgumentList MLTAL, LocalInstantiationScope &Scope) {
@@ -684,6 +736,7 @@ bool Sema::CheckFunctionConstraints(const FunctionDecl *FD,
CtxToSave = CtxToSave->getNonTransparentContext();
}
+ const bool shouldAddDeclsFromParentScope = !CtxToSave->Encloses(CurContext);
ContextRAII SavedContext{*this, CtxToSave};
LocalInstantiationScope Scope(*this, !ForOverloadResolution ||
isLambdaCallOperator(FD));
@@ -705,6 +758,9 @@ bool Sema::CheckFunctionConstraints(const FunctionDecl *FD,
LambdaScopeForCallOperatorInstantiationRAII LambdaScope(
*this, const_cast<FunctionDecl *>(FD), *MLTAL, Scope);
+ if (isLambdaCallOperator(FD) && shouldAddDeclsFromParentScope)
+ addDeclsFromParentScope(*this, const_cast<FunctionDecl *>(FD), Scope);
+
return CheckConstraintSatisfaction(
FD, {FD->getTrailingRequiresClause()}, *MLTAL,
SourceRange(UsageLoc.isValid() ? UsageLoc : FD->getLocation()),
@@ -896,6 +952,9 @@ bool Sema::CheckInstantiatedFunctionTemplateConstraints(
LambdaScopeForCallOperatorInstantiationRAII LambdaScope(
*this, const_cast<FunctionDecl *>(Decl), *MLTAL, Scope);
+ if (isLambdaCallOperator(Decl))
+ addDeclsFromParentScope(*this, Decl, Scope);
+
llvm::SmallVector<Expr *, 1> Converted;
return CheckConstraintSatisfaction(Template, TemplateAC, Converted, *MLTAL,
PointOfInstantiation, Satisfaction);
diff --git a/clang/test/SemaCXX/pr64462.cpp b/clang/test/SemaCXX/pr64462.cpp
new file mode 100644
index 000000000000000..cc8b5510d1a823a
--- /dev/null
+++ b/clang/test/SemaCXX/pr64462.cpp
@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 -verify -std=c++20 -fsyntax-only %s
+
+auto c1(auto f, auto ...fs) {
+ constexpr bool a = true;
+ // expected-note@+2{{because substituted constraint expression is
ill-formed: no matching function for call to 'c1'}}
+ // expected-note@+1{{candidate template ignored: constraints not satisfied
[with auto:1 = bool}}
+ return [](auto) requires a && (c1(fs...)) {};
+}
+
+auto c2(auto f, auto ...fs) {
+ constexpr bool a = true;
+ // expected-note@+2{{because substituted constraint expression is
ill-formed: no matching function for call to 'c2'}}
+ // expected-note@+1{{candidate function not viable: constraints not
satisfied}}
+ return []() requires a && (c2(fs...)) {};
+}
+
+void foo() {
+ c1(true)(true); // expected-error {{no matching function for call to object
of type}}
+ c2(true)(); // expected-error {{no matching function for call to object of
type}}
+}
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