[Clang] Ensure the instantiation of array initializers for decltype/_typeof operator

[zyn0217]

This is a follow-up to a967251, per Richard's suggestion we should ensure the instantiation for these unevaluated operators as well.

No release entry because the issue being fixed was already claimed resolved in that patch (though not intended).

Fixes #79750

[llvmbot]

@llvm/pr-subscribers-clang

Author: Younan Zhang (zyn0217)

Changes

This is a follow-up to a967251, per Richard's suggestion we should ensure the instantiation for these unevaluated operators as well.

No release entry because the issue being fixed was already claimed resolved in that patch (though not intended).

Fixes #79750

---

Full diff: https://github.com/llvm/llvm-project/pull/133575.diff

2 Files Affected:

• (modified) clang/lib/Sema/SemaType.cpp (+3)
• (modified) clang/test/SemaCXX/cxx1y-variable-templates_top_level.cpp (+12)

diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp index 776d6e55acc18..4b1a44d378f38 100644 --- a/clang/lib/Sema/SemaType.cpp +++ b/clang/lib/Sema/SemaType.cpp @@ -9544,6 +9544,7 @@ QualType Sema::BuildTypeofExprType(Expr *E, TypeOfKind Kind) { QualType T = E->getType(); if (const TagType *TT = T->getAs<TagType>()) DiagnoseUseOfDecl(TT->getDecl(), E->getExprLoc()); + getCompletedType(E); } return Context.getTypeOfExprType(E, Kind); } @@ -9589,6 +9590,8 @@ QualType Sema::getDecltypeForExpr(Expr *E) { if (E->isTypeDependent()) return Context.DependentTy; + getCompletedType(IDExpr); + // C++11 [dcl.type.simple]p4: // The type denoted by decltype(e) is defined as follows: diff --git a/clang/test/SemaCXX/cxx1y-variable-templates_top_level.cpp b/clang/test/SemaCXX/cxx1y-variable-templates_top_level.cpp index 6fc2032ee7fb4..7fcc688d7fd1b 100644 --- a/clang/test/SemaCXX/cxx1y-variable-templates_top_level.cpp +++ b/clang/test/SemaCXX/cxx1y-variable-templates_top_level.cpp @@ -472,6 +472,18 @@ namespace VexingParse { namespace GH79750 { +template <unsigned...values> +constexpr unsigned array[]{ values... }; + +// Test if the unevaluated operators trigger instantiation of the array initializer. +static_assert(__is_same(__typeof(array<1, 2, 3, 4, 5>), const unsigned[5]), ""); + +static_assert(__is_same(decltype(array<1, 2, 3, 4>), const unsigned[4]), ""); + +} + +namespace GH79750_2 { + enum class Values { A }; template<typename E> 

[cor3ntin]

I find myself wanting a RequireCompleteType (or just CompletesType - maybe with asserts that check that the resulting types is indeed complete) overload that does not take a diagnostic. getCompletedType does not make it clear what it does. And comments would help

[zyn0217]

I find myself wanting a RequireCompleteType (or just CompletesType - maybe with asserts that check that the resulting types is indeed complete) overload that does not take a diagnostic. getCompletedType does not make it clear what it does. And comments would help

Humm, I didn't use RequireCompleteExprType because it is allowed to be incomplete:

https://godbolt.org/z/5s6s7hn7e

[efriedma-quic]

I'm not sure we want to scatter checks across the code for specific expressions. See #133963. Maybe we should just immediately fix the type when the declaration is referenced?