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[clang] Fix possible nullptr deref in BuildCXXNestedNameSpecifier #166995

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Merged
merged 7 commits into from
Nov 10, 2025
Merged

[clang] Fix possible nullptr deref in BuildCXXNestedNameSpecifier #166995

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dbedc1c
[clang] Fix possible nullptr deref in BuildCXXNestedNameSpecifier
ilovepi Nov 7, 2025
be21d3d
Prefer early return to avoid excessive diff
ilovepi Nov 7, 2025
5796fc8
Add missing test case that wasn't uploaded
ilovepi Nov 7, 2025
1f6e1b6
Fix formatting
ilovepi Nov 7, 2025
b07be58
Merge branch 'main' into clang-deref-null
ilovepi Nov 7, 2025
7010a50
Merge branch 'main' into clang-deref-null
ilovepi Nov 7, 2025
710b262
Ensure correct diagnostic still gets used
ilovepi Nov 7, 2025
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39 changes: 20 additions & 19 deletions clang/lib/Sema/SemaCXXScopeSpec.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -779,25 +779,26 @@ bool Sema::BuildCXXNestedNameSpecifier(Scope *S, NestedNameSpecInfo &IdInfo,
}

if (!Found.empty()) {
const auto *ND = Found.getAsSingle<NamedDecl>();
if (::ExtendNestedNameSpecifier(*this, SS, ND, IdInfo.IdentifierLoc,
IdInfo.CCLoc)) {
const Type *T = SS.getScopeRep().getAsType();
Diag(IdInfo.IdentifierLoc, diag::err_expected_class_or_namespace)
<< QualType(T, 0) << getLangOpts().CPlusPlus;
// Recover with this type if it would be a valid nested name specifier.
return !T->getAsCanonical<TagType>();
}
if (isa<TemplateDecl>(ND)) {
ParsedType SuggestedType;
DiagnoseUnknownTypeName(IdInfo.Identifier, IdInfo.IdentifierLoc, S, &SS,
SuggestedType);
} else {
Diag(IdInfo.IdentifierLoc, diag::err_expected_class_or_namespace)
<< IdInfo.Identifier << getLangOpts().CPlusPlus;
if (NamedDecl *ND = Found.getAsSingle<NamedDecl>())
Diag(ND->getLocation(), diag::note_entity_declared_at)
<< IdInfo.Identifier;
if (const auto *ND = Found.getAsSingle<NamedDecl>()) {
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@mizvekov mizvekov Nov 7, 2025

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Please bail out early to reduce the diff.

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@ilovepi ilovepi Nov 7, 2025

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done.

if (::ExtendNestedNameSpecifier(*this, SS, ND, IdInfo.IdentifierLoc,
IdInfo.CCLoc)) {
const Type *T = SS.getScopeRep().getAsType();
Diag(IdInfo.IdentifierLoc, diag::err_expected_class_or_namespace)
<< QualType(T, 0) << getLangOpts().CPlusPlus;
// Recover with this type if it would be a valid nested name specifier.
return !T->getAsCanonical<TagType>();
}
if (isa<TemplateDecl>(ND)) {
ParsedType SuggestedType;
DiagnoseUnknownTypeName(IdInfo.Identifier, IdInfo.IdentifierLoc, S, &SS,
SuggestedType);
} else {
Diag(IdInfo.IdentifierLoc, diag::err_expected_class_or_namespace)
<< IdInfo.Identifier << getLangOpts().CPlusPlus;
if (NamedDecl *ND = Found.getAsSingle<NamedDecl>())
Diag(ND->getLocation(), diag::note_entity_declared_at)
<< IdInfo.Identifier;
}
}
} else if (SS.isSet())
Diag(IdInfo.IdentifierLoc, diag::err_no_member) << IdInfo.Identifier
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