use of dependent type name must be prefixed

[_Flaviu]

I have a code:

//add any arg # function to queue
template
auto Add(Func&& f, Args&&... args)
{
//get return type of the function
using RetType = std::invoke_result_t;

and on last line, at compiling time I got: error C7510: 'invoke_result_t': use of dependent type name must be prefixed with 'typename' How can I overcome this error ?

[Greg Utas]

I believe that typename is supposed the be prefixed to tell the compiler that invoke_result_t is defining a type:

using RetType = std::typename invoke_result_t;

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[_Flaviu]

I have tried:

using RetType = std::typename invoke_result_t;

but I got: error C2589: 'typename': illegal token on right side of '::'

[Greg Utas]

Try moving it to the front:

using RetType = typename std::invoke_result_t;

This[^] may be of help.

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[_Flaviu]

I already did:

using RetType = typename std::invoke_result_t;

Result: error C2760: syntax error: unexpected token '<', expected ';'

[Lost User]

See std::result_of, std::invoke_result - cppreference.com[^], which suggests the word typename goes before std::invoke_result_t. Although the discussion is less clear than it could be.

[Greg Utas]

See "Helper types" on this page[^]. It looks like invoke_result_t is itself a type alias. Try std::invoke_result without the _t.

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