[clang] [Clang] Avoid querying tag definitions for invalid DeclSpecs (PR #210085)

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llvmorg-github-actions[bot] wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Osama Abdelkader (osamakader)

<details>
<summary>Changes</summary>

Guard hasTagDefinition() against invalid type-specifier state so recovery from invalid auto/tag combinations does not assert.
Fixes #<!-- -->210014 

---
Full diff: https://github.com/llvm/llvm-project/pull/210085.diff


2 Files Affected:

- (modified) clang/lib/Sema/DeclSpec.cpp (+1-1) 
- (modified) clang/test/SemaCXX/auto-cxx0x.cpp (+3) 


``````````diff
diff --git a/clang/lib/Sema/DeclSpec.cpp b/clang/lib/Sema/DeclSpec.cpp
index 4d20657d5e517..9df12d0c4ce75 100644
--- a/clang/lib/Sema/DeclSpec.cpp
+++ b/clang/lib/Sema/DeclSpec.cpp
@@ -431,7 +431,7 @@ void DeclSpec::forEachQualifier(
 }
 
 bool DeclSpec::hasTagDefinition() const {
-  if (!TypeSpecOwned)
+  if (!TypeSpecOwned || !isDeclRep((TST)TypeSpecType))
     return false;
   return cast<TagDecl>(getRepAsDecl())->isCompleteDefinition();
 }
diff --git a/clang/test/SemaCXX/auto-cxx0x.cpp b/clang/test/SemaCXX/auto-cxx0x.cpp
index fa953f35723ef..ff2c98fce7523 100644
--- a/clang/test/SemaCXX/auto-cxx0x.cpp
+++ b/clang/test/SemaCXX/auto-cxx0x.cpp
@@ -14,6 +14,9 @@ void f() {
 struct PR209000 {
 } auto; // expected-error {{'auto' cannot be combined with a type specifier}}
 
+auto union { // expected-error {{cannot combine with previous 'auto' declaration specifier}}
+} foo<>; // expected-error {{no template named 'foo'}}
+
 typedef auto PR25449(); // expected-error {{'auto' not allowed in typedef}}
 
 thread_local auto x; // expected-error {{requires an initializer}}

``````````

</details>


https://github.com/llvm/llvm-project/pull/210085