This revision was automatically updated to reflect the committed changes.
Closed by commit rG79f9cfbc21e0: Do not merge LocalInstantiationScope for
template specialization (authored by yaxunl).
Herald added a project: clang.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D98068/new/
https://reviews.llvm.org/D98068
Files:
clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
clang/test/SemaCXX/recursive-lambda.cpp
Index: clang/test/SemaCXX/recursive-lambda.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/recursive-lambda.cpp
@@ -0,0 +1,38 @@
+// RUN: %clang_cc1 -std=c++17 -fsyntax-only -verify %s
+
+// expected-no-diagnostics
+
+// Check recursive instantiation of lambda does not cause assertion.
+// lambda function `f` in `fun1` is instantiated twice: first
+// as f(f, Number<1>), then as f(f, Number<0>). The
+// LocalInstantiationScopes of these two instantiations both contain
+// `f` and `i`. However, since they are not merged, clang should not
+// assert for that.
+
+template <unsigned v>
+struct Number
+{
+ static constexpr unsigned value = v;
+};
+
+template <unsigned IBegin = 0,
+ unsigned IEnd = 1>
+constexpr auto fun1(Number<IBegin> = Number<0>{}, Number<IEnd> = Number<1>{})
+{
+ constexpr unsigned a = 0;
+ auto f = [&](auto fs, auto i) {
+ if constexpr(i.value > 0)
+ {
+ (void)a;
+ return fs(fs, Number<IBegin>{});
+ }
+ (void)a;
+ };
+
+ return f(f, Number<IEnd>{});
+}
+
+
+void fun2() {
+ fun1();
+}
Index: clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
===================================================================
--- clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -4890,10 +4890,13 @@
// Introduce a new scope where local variable instantiations will be
// recorded, unless we're actually a member function within a local
// class, in which case we need to merge our results with the parent
- // scope (of the enclosing function).
+ // scope (of the enclosing function). The exception is instantiating
+ // a function template specialization, since the template to be
+ // instantiated already has references to locals properly substituted.
bool MergeWithParentScope = false;
if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
- MergeWithParentScope = Rec->isLocalClass();
+ MergeWithParentScope =
+ Rec->isLocalClass() && !Function->isFunctionTemplateSpecialization();
LocalInstantiationScope Scope(*this, MergeWithParentScope);
Index: clang/test/SemaCXX/recursive-lambda.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/recursive-lambda.cpp
@@ -0,0 +1,38 @@
+// RUN: %clang_cc1 -std=c++17 -fsyntax-only -verify %s
+
+// expected-no-diagnostics
+
+// Check recursive instantiation of lambda does not cause assertion.
+// lambda function `f` in `fun1` is instantiated twice: first
+// as f(f, Number<1>), then as f(f, Number<0>). The
+// LocalInstantiationScopes of these two instantiations both contain
+// `f` and `i`. However, since they are not merged, clang should not
+// assert for that.
+
+template <unsigned v>
+struct Number
+{
+ static constexpr unsigned value = v;
+};
+
+template <unsigned IBegin = 0,
+ unsigned IEnd = 1>
+constexpr auto fun1(Number<IBegin> = Number<0>{}, Number<IEnd> = Number<1>{})
+{
+ constexpr unsigned a = 0;
+ auto f = [&](auto fs, auto i) {
+ if constexpr(i.value > 0)
+ {
+ (void)a;
+ return fs(fs, Number<IBegin>{});
+ }
+ (void)a;
+ };
+
+ return f(f, Number<IEnd>{});
+}
+
+
+void fun2() {
+ fun1();
+}
Index: clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
===================================================================
--- clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -4890,10 +4890,13 @@
// Introduce a new scope where local variable instantiations will be
// recorded, unless we're actually a member function within a local
// class, in which case we need to merge our results with the parent
- // scope (of the enclosing function).
+ // scope (of the enclosing function). The exception is instantiating
+ // a function template specialization, since the template to be
+ // instantiated already has references to locals properly substituted.
bool MergeWithParentScope = false;
if (CXXRecordDecl *Rec = dyn_cast<CXXRecordDecl>(Function->getDeclContext()))
- MergeWithParentScope = Rec->isLocalClass();
+ MergeWithParentScope =
+ Rec->isLocalClass() && !Function->isFunctionTemplateSpecialization();
LocalInstantiationScope Scope(*this, MergeWithParentScope);
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