Index: clang/lib/AST/ASTContext.cpp
===================================================================
--- clang/lib/AST/ASTContext.cpp
+++ clang/lib/AST/ASTContext.cpp
@@ -10030,6 +10030,9 @@
     return false;
 
   ObjCTypeParamList *typeParams = iface->getTypeParamList();
+  if (!typeParams)
+    return std::nullopt;
+
   for (unsigned i = 0, n = lhsArgs.size(); i != n; ++i) {
     if (ctx.hasSameType(lhsArgs[i], rhsArgs[i]))
       continue;
Index: clang/lib/AST/MicrosoftMangle.cpp
===================================================================
--- clang/lib/AST/MicrosoftMangle.cpp
+++ clang/lib/AST/MicrosoftMangle.cpp
@@ -2693,7 +2693,7 @@
         // Copy constructor closure always takes an unqualified reference.
         mangleFunctionArgumentType(getASTContext().getLValueReferenceType(
                                        Proto->getParamType(0)
-                                           ->getAs<LValueReferenceType>()
+                                           ->castAs<LValueReferenceType>()
                                            ->getPointeeType(),
                                        /*SpelledAsLValue=*/true),
                                    Range);
Index: clang/lib/Analysis/ThreadSafety.cpp
===================================================================
--- clang/lib/Analysis/ThreadSafety.cpp
+++ clang/lib/Analysis/ThreadSafety.cpp
@@ -504,6 +504,8 @@
       D->printName(llvm::errs());
       const unsigned *i = C.lookup(D);
       llvm::errs() << " -> ";
+      if (!i)
+        return nullptr;
       dumpVarDefinitionName(*i);
       llvm::errs() << "\n";
     }
Index: clang/lib/CodeGen/CGOpenMPRuntimeGPU.cpp
===================================================================
--- clang/lib/CodeGen/CGOpenMPRuntimeGPU.cpp
+++ clang/lib/CodeGen/CGOpenMPRuntimeGPU.cpp
@@ -3365,7 +3365,7 @@
   if (getDataSharingMode(CGM) != CGOpenMPRuntimeGPU::Generic)
     return Address::invalid();
 
-  VD = VD->getCanonicalDecl();
+  VD = cast<VarDecl>(VD->getCanonicalDecl());
   auto I = FunctionGlobalizedDecls.find(CGF.CurFn);
   if (I == FunctionGlobalizedDecls.end())
     return Address::invalid();
Index: clang/lib/Sema/SemaExpr.cpp
===================================================================
--- clang/lib/Sema/SemaExpr.cpp
+++ clang/lib/Sema/SemaExpr.cpp
@@ -4955,7 +4955,8 @@
   };
   // The matrix subscript operator ([][])is considered a single operator.
   // Separating the index expressions by parenthesis is not allowed.
-  if (base->hasPlaceholderType(BuiltinType::IncompleteMatrixIdx) &&
+  if (base && !base->getType().isNull() &&
+      base->hasPlaceholderType(BuiltinType::IncompleteMatrixIdx) &&
       !isa<MatrixSubscriptExpr>(base)) {
     Diag(base->getExprLoc(), diag::err_matrix_separate_incomplete_index)
         << SourceRange(base->getBeginLoc(), rbLoc);