In C++11 non static member functions now support reference qualifiers. For the un-initiated they go after the function declaration/definition and can be combined with const and/or volatile. Just like the const and volatile qualifiers they allow overloading the function on the type of the implicit object parameter ("this").

struct foo {
	foo();
	void bar() & ; //1. Lvalue reference qualifier
	void bar() &&; //2. Rvalue reference qualifier
};

void myfunc() {
	foo f;
	f.bar(); //Calls 1 since the implicit object parameter is an lvalue
	foo().bar(); //Calls 2 since the implicit object parameter is an rvalue
}

1 and 2 are treated as syntax errors by KDevelop and as an obvious side effect completion for those functions is not available either.

Reproducible: Always

Steps to Reproduce:
1. Enter the example provided into a C++ file 
2. Compile as C++11 (currently clang 3.1 is the only compiler i have that understands this)
Actual Results:  
KDevelop flags a syntax error even though it is valid C++11 and successfully compiles.

Expected Results:  
KDevelop should accept the syntax and understand it for the purpose of completion although simply accepting it as valid syntax but acting as if the reference qualifiers are not present would be a great start since then completion could presumably work even if filtering out completions by context wouldn't.