[Clang] Evaluate dependent indexes of pack indexing in a constant context #106054
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@llvm/pr-subscribers-clang Author: cor3ntin (cor3ntin) ChangesFixes #105900 Full diff: https://github.com/llvm/llvm-project/pull/106054.diff 3 Files Affected:
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 8f98167dff31ef..384471bf860c5b 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -292,6 +292,7 @@ Bug Fixes to C++ Support
- Correctly check constraints of explicit instantiations of member functions. (#GH46029)
- Fixed an assertion failure about a constraint of a friend function template references to a value with greater
template depth than the friend function template. (#GH98258)
+- Fix evaluation of the index of dependent pack indexing expressions/types specifiers (#GH105900)
Bug Fixes to AST Handling
^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index 62287c2d26375c..b3854cd8f82220 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -6669,9 +6669,15 @@ QualType
TreeTransform<Derived>::TransformPackIndexingType(TypeLocBuilder &TLB,
PackIndexingTypeLoc TL) {
// Transform the index
- ExprResult IndexExpr = getDerived().TransformExpr(TL.getIndexExpr());
- if (IndexExpr.isInvalid())
- return QualType();
+ ExprResult IndexExpr;
+ {
+ EnterExpressionEvaluationContext ConstantContext(
+ SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);
+
+ IndexExpr = getDerived().TransformExpr(TL.getIndexExpr());
+ if (IndexExpr.isInvalid())
+ return QualType();
+ }
QualType Pattern = TL.getPattern();
const PackIndexingType *PIT = TL.getTypePtr();
@@ -15299,9 +15305,14 @@ TreeTransform<Derived>::TransformPackIndexingExpr(PackIndexingExpr *E) {
return E;
// Transform the index
- ExprResult IndexExpr = getDerived().TransformExpr(E->getIndexExpr());
- if (IndexExpr.isInvalid())
- return ExprError();
+ ExprResult IndexExpr;
+ {
+ EnterExpressionEvaluationContext ConstantContext(
+ SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);
+ IndexExpr = getDerived().TransformExpr(E->getIndexExpr());
+ if (IndexExpr.isInvalid())
+ return ExprError();
+ }
SmallVector<Expr *, 5> ExpandedExprs;
if (!E->expandsToEmptyPack() && E->getExpressions().empty()) {
diff --git a/clang/test/SemaCXX/cxx2c-pack-indexing.cpp b/clang/test/SemaCXX/cxx2c-pack-indexing.cpp
index 9ea90a4c3e30fd..37dceaee64fac2 100644
--- a/clang/test/SemaCXX/cxx2c-pack-indexing.cpp
+++ b/clang/test/SemaCXX/cxx2c-pack-indexing.cpp
@@ -231,3 +231,30 @@ struct type_info {
namespace GH93650 {
auto func(auto... inputArgs) { return typeid(inputArgs...[0]); }
} // namespace GH93650
+
+
+namespace GH105900 {
+
+template <typename... opts>
+struct types {
+ template <unsigned idx>
+ static constexpr __SIZE_TYPE__ get_index() { return idx; }
+
+ template <unsigned s>
+ static auto x() -> opts...[get_index<s>()] {}
+};
+
+template <auto... opts>
+struct vars {
+ template <unsigned idx>
+ static constexpr __SIZE_TYPE__ get_index() { return idx; }
+
+ template <unsigned s>
+ static auto x() -> decltype(opts...[get_index<s>()]) {return 0;}
+};
+
+void f() {
+ types<void>::x<0>(); // Error
+ vars<0>::x<0>(); // Error
+}
+}
|
zyn0217
approved these changes
Aug 26, 2024
Comment on lines
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| types<void>::x<0>(); // Error | ||
| vars<0>::x<0>(); // Error |
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| types<void>::x<0>(); // Error | |
| vars<0>::x<0>(); // Error | |
| types<void>::x<0>(); | |
| vars<0>::x<0>(); |
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/179/builds/4976 Here is the relevant piece of the build log for the reference |
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Fixes #105900