Don’t dive into null parts of AST.

Author: davidungar

lib/AST/USRGeneration.cpp

@@ -226,7 +226,7 @@ bool ide::printDeclUSR(const ValueDecl *D, raw_ostream &OS) {
     return printObjCUSR(D, OS);
   }
 
-  if (!D->hasInterfaceType())
+  if (!D->hasInterfaceType() || D->getInterfaceType()->is<ErrorType>())
     return true;
 
   // Invalid code.

lib/IDE/SourceEntityWalker.cpp

@@ -247,6 +247,8 @@ static SemaReferenceKind getReferenceKind(Expr *Parent, Expr *E) {
 }
 
 std::pair<bool, Expr *> SemaAnnotator::walkToExprPre(Expr *E) {
+  assert(E);
+
   if (isDone())
     return { false, nullptr };
 
@@ -409,11 +411,11 @@ std::pair<bool, Expr *> SemaAnnotator::walkToExprPre(Expr *E) {
       llvm::SaveAndRestore<Optional<AccessKind>>
         C(this->OpAccess, AccessKind::Write);
 
-      if (!AE->getDest()->walk(*this))
+      if (AE->getDest() && !AE->getDest()->walk(*this))
         return { false, nullptr };
     }
 
-    if (!AE->getSrc()->walk(*this))
+    if (AE->getSrc() && !AE->getSrc()->walk(*this))
       return { false, nullptr };
 
     // We already visited the children.