CppTools: Do not highlight instantiation as call

Underlying C++ model sometimes marks C++ object instantiation using initializer
as a (forward) function declaration. This leads to incorrect highlighting of
object variables as if they were function calls.

C++ model however marks in this case (and not any other case) such symbols as
ambiguous function types, see CPlusPlus::Bind::visit. This change skips such
ambiguous functions for highlighting as function call.

Also add test case for related bug report.

Task-number: QTCREATORBUG-15212
Change-Id: Ifde8db407f2fa8275a3f991bfa3d3b73eca8c14e
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@theqtcompany.com>

src/plugins/cpptools/cppchecksymbols.cpp

@@ -1298,7 +1298,7 @@ bool CheckSymbols::maybeAddFunction(const QList<LookupItem> &candidates, NameAST
         Function *funTy = c->type()->asFunctionType();
         if (!funTy) // Template function has an overridden type
             funTy = r.type()->asFunctionType();
-        if (!funTy)
+        if (!funTy || funTy->isAmbiguous())
             continue; // TODO: add diagnostic messages and color call-operators calls too?
 
         if (argumentCount < funTy->minimumArgumentCount()) {

tests/auto/cplusplus/checksymbols/tst_checksymbols.cpp

@@ -1022,6 +1022,55 @@ void tst_CheckSymbols::test_checksymbols_data()
             << Use(3, 3, 7, Highlighting::LocalUse)
             << Use(3, 11, 10, Highlighting::FieldUse));
 
+    QTest::newRow("instantation_as_function_call_QTCREATORBUG15212")
+        << _("struct Foo {};\n"
+             "template <typename Type> struct test {\n"
+             "  test() {}\n"
+             "  test(int, int) {}\n"
+             "};\n"
+             "void test(int int_argument) {\n"
+             "  const int very_long_constant_of_type_int = 11111111111111111;\n"
+             "  test<Foo> foo1;\n"
+             "  test<Foo> foo2(int_argument, int_argument);\n"
+             "  test<Foo> foo3(very_long_constant_of_type_int,\n"
+             "                 very_long_constant_of_type_int);\n"
+             "  test<int> size1(int_argument, int_argument);\n"
+             "  (void)foo1, foo2, foo3, size1;\n"
+             "  test(int_argument);\n"
+             "}\n")
+        << (UseList()
+            << Use(1, 8, 3, Highlighting::TypeUse)
+            << Use(2, 20, 4, Highlighting::TypeUse)
+            << Use(2, 33, 4, Highlighting::TypeUse)
+            << Use(3, 3, 4, Highlighting::TypeUse)
+            << Use(4, 3, 4, Highlighting::TypeUse)
+            << Use(6, 6, 4, Highlighting::FunctionUse)
+            << Use(6, 15, 12, Highlighting::LocalUse)
+            << Use(7, 13, 30, Highlighting::LocalUse)
+            << Use(8, 3, 4, Highlighting::TypeUse)
+            << Use(8, 8, 3, Highlighting::TypeUse)
+            << Use(8, 13, 4, Highlighting::LocalUse)
+            << Use(9, 3, 4, Highlighting::TypeUse)
+            << Use(9, 8, 3, Highlighting::TypeUse)
+            << Use(9, 13, 4, Highlighting::LocalUse)
+            << Use(9, 18, 12, Highlighting::LocalUse)
+            << Use(9, 32, 12, Highlighting::LocalUse)
+            << Use(10, 3, 4, Highlighting::TypeUse)
+            << Use(10, 8, 3, Highlighting::TypeUse)
+            << Use(10, 13, 4, Highlighting::LocalUse)
+            << Use(10, 18, 30, Highlighting::LocalUse)
+            << Use(11, 18, 30, Highlighting::LocalUse)
+            << Use(12, 3, 4, Highlighting::TypeUse)
+            << Use(12, 13, 5, Highlighting::LocalUse)
+            << Use(12, 19, 12, Highlighting::LocalUse)
+            << Use(12, 33, 12, Highlighting::LocalUse)
+            << Use(13, 9, 4, Highlighting::LocalUse)
+            << Use(13, 15, 4, Highlighting::LocalUse)
+            << Use(13, 21, 4, Highlighting::LocalUse)
+            << Use(13, 27, 5, Highlighting::LocalUse)
+            << Use(14, 3, 4, Highlighting::FunctionUse)
+            << Use(14, 8, 12, Highlighting::LocalUse));
+
     QTest::newRow("unicodeIdentifier1")
         << _("class My" TEST_UNICODE_IDENTIFIER "Type { int " TEST_UNICODE_IDENTIFIER "Member; };\n"
              "void f(My" TEST_UNICODE_IDENTIFIER "Type var" TEST_UNICODE_IDENTIFIER ")\n"