[Clang] Raise an error on namespace aliases with qualified names. (#8…

…6122)
llvm · Mar 22, 2024 · 0024875 · 0024875
1 parent 7fc2fbb
commit 0024875
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diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
@@ -437,6 +437,8 @@ Bug Fixes to C++ Support
 - Clang's __builtin_bit_cast will now produce a constant value for records with empty bases. See:
   (#GH82383)
 - Fix a crash when instantiating a lambda that captures ``this`` outside of its context. Fixes (#GH85343).
+- Fix an issue where a namespace alias could be defined using a qualified name (all name components
+  following the first `::` were ignored).
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^

diff --git a/clang/include/clang/Basic/DiagnosticParseKinds.td b/clang/include/clang/Basic/DiagnosticParseKinds.td
@@ -268,6 +268,8 @@ def err_expected_semi_after_namespace_name : Error<
   "expected ';' after namespace name">;
 def err_unexpected_namespace_attributes_alias : Error<
   "attributes cannot be specified on namespace alias">;
+def err_unexpected_qualified_namespace_alias : Error<
+  "namespace alias must be a single identifier">;
 def err_unexpected_nested_namespace_attribute : Error<
   "attributes cannot be specified on a nested namespace definition">;
 def err_inline_namespace_alias : Error<"namespace alias cannot be inline">;

diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -140,6 +140,14 @@ Parser::DeclGroupPtrTy Parser::ParseNamespace(DeclaratorContext Context,
       SkipUntil(tok::semi);
       return nullptr;
     }
+    if (!ExtraNSs.empty()) {
+      Diag(ExtraNSs.front().NamespaceLoc,
+           diag::err_unexpected_qualified_namespace_alias)
+          << SourceRange(ExtraNSs.front().NamespaceLoc,
+                         ExtraNSs.back().IdentLoc);
+      SkipUntil(tok::semi);
+      return nullptr;
+    }
     if (attrLoc.isValid())
       Diag(attrLoc, diag::err_unexpected_namespace_attributes_alias);
     if (InlineLoc.isValid())

diff --git a/clang/test/SemaCXX/namespace-alias.cpp b/clang/test/SemaCXX/namespace-alias.cpp
@@ -47,6 +47,8 @@ namespace I {
   namespace A1 { int i; }
 
   namespace A2 = A1;
+
+  namespace A3::extra::specifiers = A2;  // expected-error {{alias must be a single identifier}}
 }
 
 int f() {