[libclang] Fix crash in member access code completion with implicit base

If there is an unresolved member access AST node, and the base is
implicit, do not access/use it for generating candidate overloads for
code completion results.

Fixes PR31093.

llvm-svn: 298903

1 files changed, 26 insertions, 11 deletions

diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 82834057ee2..bba8216fa2b 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -6307,30 +6307,45 @@ void Sema::AddFunctionCandidates(const UnresolvedSetImpl &Fns,
   for (UnresolvedSetIterator F = Fns.begin(), E = Fns.end(); F != E; ++F) {
     NamedDecl *D = F.getDecl()->getUnderlyingDecl();
     if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
-      if (isa<CXXMethodDecl>(FD) && !cast<CXXMethodDecl>(FD)->isStatic())
+      if (isa<CXXMethodDecl>(FD) && !cast<CXXMethodDecl>(FD)->isStatic()) {
+        QualType ObjectType;
+        Expr::Classification ObjectClassification;
+        if (Expr *E = Args[0]) {
+          // Use the explit base to restrict the lookup:
+          ObjectType = E->getType();
+          ObjectClassification = E->Classify(Context);
+        } // .. else there is an implit base.
         AddMethodCandidate(cast<CXXMethodDecl>(FD), F.getPair(),
-                           cast<CXXMethodDecl>(FD)->getParent(),
-                           Args[0]->getType(), Args[0]->Classify(Context),
-                           Args.slice(1), CandidateSet, SuppressUserConversions,
-                           PartialOverloading);
-      else
+                           cast<CXXMethodDecl>(FD)->getParent(), ObjectType,
+                           ObjectClassification, Args.slice(1), CandidateSet,
+                           SuppressUserConversions, PartialOverloading);
+      } else {
         AddOverloadCandidate(FD, F.getPair(), Args, CandidateSet,
                              SuppressUserConversions, PartialOverloading);
+      }
     } else {
       FunctionTemplateDecl *FunTmpl = cast<FunctionTemplateDecl>(D);
       if (isa<CXXMethodDecl>(FunTmpl->getTemplatedDecl()) &&
-          !cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl())->isStatic())
+          !cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl())->isStatic()) {
+        QualType ObjectType;
+        Expr::Classification ObjectClassification;
+        if (Expr *E = Args[0]) {
+          // Use the explit base to restrict the lookup:
+          ObjectType = E->getType();
+          ObjectClassification = E->Classify(Context);
+        } // .. else there is an implit base.
         AddMethodTemplateCandidate(
             FunTmpl, F.getPair(),
             cast<CXXRecordDecl>(FunTmpl->getDeclContext()),
-            ExplicitTemplateArgs, Args[0]->getType(),
-            Args[0]->Classify(Context), Args.slice(1), CandidateSet,
-            SuppressUserConversions, PartialOverloading);
-      else
+            ExplicitTemplateArgs, ObjectType, ObjectClassification,
+            Args.slice(1), CandidateSet, SuppressUserConversions,
+            PartialOverloading);
+      } else {
         AddTemplateOverloadCandidate(FunTmpl, F.getPair(),
                                      ExplicitTemplateArgs, Args,
                                      CandidateSet, SuppressUserConversions,
                                      PartialOverloading);
+      }
     }
   }
 }