c++ - References for type deduction lambda -


i saw this answer i'm not satisfied: written in standard type deduction 'auto' not consider default arguments?

int main() {     auto lambda = [] (auto subl = [] {}) {};     lambda(); }

auto uses rules according template argument deduction ([dcl.spec.auto] /p7):

if placeholder auto type-specifier, deduced type determined using rules template argument deduction.

default arguments explicitly non-deduced context when type deduced template parameter ([temp.deduct.type]/p5):

the non-deduced contexts are:

— nested-name-specifier of type specified using qualified-id.

— expression of decltype-specifier.

— non-type template argument or array bound in subexpression references template parameter.

— a template parameter used in parameter type of function parameter has default argument being used in call argument deduction being done.


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