ClangCodeModel: Do not offer completion for inaccessible symbols

We should not offer to auto-complete e.g. private members from contexts
where they cannot legally be accessed. This is also consistent with the
existing behavior of not offering non-const members on const objects.

Fixes: QTCREATORBUG-1984
Change-Id: Ic58c1ba2dc0b8023299feebc20bec4f2a5a6ea38
Reviewed-by: Cristian Adam <cristian.adam@qt.io>

src/plugins/clangcodemodel/clangcompletionassistprocessor.cpp

@@ -132,6 +132,12 @@ static QList<AssistProposalItemInterface *> toAssistProposalItems(
         if (codeCompletion.text.isEmpty())
             continue; // It's an OverloadCandidate which has text but no typedText.
 
+        // Don't offer symbols that are not accessible here.
+        if (codeCompletion.availability == CodeCompletion::NotAvailable
+                || codeCompletion.availability == CodeCompletion::NotAccessible) {
+            continue;
+        }
+
         const QString name = codeCompletion.completionKind == CodeCompletion::KeywordCompletionKind
                 ? CompletionChunksToTextConverter::convertToName(codeCompletion.chunks)
                 : codeCompletion.text.toString();

src/plugins/clangcodemodel/test/clangcodecompletion_test.cpp

@@ -552,6 +552,30 @@ void ClangCodeCompletionTest::testCompleteMembers()
     QVERIFY(!hasSnippet(t.proposal, "class")); // Snippet
 }
 
+void ClangCodeCompletionTest::testCompleteMembersFromInside()
+{
+    ProjectLessCompletionTest t("membercompletion-inside.cpp");
+
+    QVERIFY(hasItem(t.proposal, "publicFunc"));
+    QVERIFY(hasItem(t.proposal, "privateFunc"));
+}
+
+void ClangCodeCompletionTest::testCompleteMembersFromOutside()
+{
+    ProjectLessCompletionTest t("membercompletion-outside.cpp");
+
+    QVERIFY(hasItem(t.proposal, "publicFunc"));
+    QVERIFY(!hasItem(t.proposal, "privateFunc"));
+}
+
+void ClangCodeCompletionTest::testCompleteMembersFromFriend()
+{
+    ProjectLessCompletionTest t("membercompletion-friend.cpp");
+
+    QVERIFY(hasItem(t.proposal, "publicFunc"));
+    QVERIFY(hasItem(t.proposal, "privateFunc"));
+}
+
 void ClangCodeCompletionTest::testCompleteFunctions()
 {
     ProjectLessCompletionTest t("functionCompletion.cpp");

src/plugins/clangcodemodel/test/clangcodecompletion_test.h

@@ -44,6 +44,9 @@ private slots:
 
     void testCompleteGlobals();
     void testCompleteMembers();
+    void testCompleteMembersFromInside();
+    void testCompleteMembersFromOutside();
+    void testCompleteMembersFromFriend();
     void testCompleteFunctions();
     void testCompleteConstructor();
     void testCompleteClassAndConstructor();

src/plugins/clangcodemodel/test/data/clangtestdata.qrc

@@ -24,5 +24,8 @@
         <file>dotToArrowCorrection.cpp</file>
         <file>noDotToArrowCorrectionForFloats.cpp</file>
         <file>classAndConstructorCompletion.cpp</file>
+        <file>membercompletion-outside.cpp</file>
+        <file>membercompletion-inside.cpp</file>
+        <file>membercompletion-friend.cpp</file>
     </qresource>
 </RCC>

src/plugins/clangcodemodel/test/data/membercompletion-friend.cpp

@@ -0,0 +1,15 @@
+static void friendFunc();
+
+class C {
+    friend void friendFunc();
+public:
+    void publicFunc() {};
+
+private:
+    void privateFunc() {}
+};
+
+void friendFunc()
+{
+    C().p /* COMPLETE HERE */
+}

src/plugins/clangcodemodel/test/data/membercompletion-inside.cpp

@@ -0,0 +1,11 @@
+class C {
+public:
+    C() {
+        p /* COMPLETE HERE */
+    }
+    void publicFunc() {};
+
+private:
+    void privateFunc() {}
+};
+

src/plugins/clangcodemodel/test/data/membercompletion-outside.cpp

@@ -0,0 +1,15 @@
+class C {
+public:
+    C() {}
+    void publicFunc() {};
+
+private:
+    void privateFunc() {}
+};
+
+void f()
+{
+    C c;
+    c.p /* COMPLETE HERE */
+}
+