[clang] Fix assertion fail when function has cleanups and fatal errors

[Fznamznon]

Summary

Fixes https://github.com/llvm/llvm-project/issues/48974

[shafik]

Thank you for the fix! LGTM

clang/docs/ReleaseNotes.rst

- Fixed an issue where accesses to the local variables of a coroutine during
   object itself.
   (`#56301 <https://github.com/llvm/llvm-project/issues/56301>`_)
   The current solution may bring performance regressions if the awaiters have
   non-static data members. See
   `#64945 <https://github.com/llvm/llvm-project/issues/64945>`_ for details.
 - Clang now prints unnamed members in diagnostic messages instead of giving an
   empty ''. Fixes
   (`#63759 <https://github.com/llvm/llvm-project/issues/63759>`_)
+- Fixed an assertion if a function has cleanups and fatal erors.
+  (`#48974 <https://github.com/llvm/llvm-project/issues/48974>`_)
 
 Bug Fixes to Compiler Builtins
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 Bug Fixes to Attribute Support
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 Bug Fixes to C++ Support

clang/lib/Sema/SemaDecl.cpp

if (Body && (!FD || !FD->isDefaulted())) {
         MarkBaseAndMemberDestructorsReferenced(Destructor->getLocation(),
                                                Destructor->getParent());
       }
 
       // If any errors have occurred, clear out any temporaries that may have
       // been leftover. This ensures that these temporaries won't be picked up
       // for deletion in some later function.
       if (hasUncompilableErrorOccurred() ||
+          hasAnyUnrecoverableErrorsInThisFunction() ||
           getDiagnostics().getSuppressAllDiagnostics()) {
         DiscardCleanupsInEvaluationContext();
       }
       if (!hasUncompilableErrorOccurred() && !isa<FunctionTemplateDecl>(dcl)) {
         // Since the body is valid, issue any analysis-based warnings that are
         // enabled.
         ActivePolicy = &WP;
       }

clang/test/SemaCXX/gh48974.cpp

+// RUN: %clang_cc1 -Werror=unused-parameter -Wfatal-errors -verify %s
+
+void a(int &&s) {} // expected-error{{unused parameter 's'}}
+
+void b() {
+  int sum = a(0);
+}