Bug 24686 – SumType stopped working on LDC 1.37 with unmatched DeducedParameterType template

Compiling an argument parser (cant really deduce the code snippet) 63874b2ce32b165436d3007515377ef5d5dce22d version of https://github.com/andrey-zherikov/argparse yields the following error on LDC 1.37 and beyond. ``` /home/luis/.local/bin/../import/std/sumtype.d(418): Error: template instance `DeducedParameterType!(inout(Unknown))` does not match template declaration `DeducedParameterType(T)` /home/luis/.local/bin/../import/std/sumtype.d(418): Error: template instance `DeducedParameterType!(inout(Argument))` does not match template declaration `DeducedParameterType(T)` /home/luis/.local/bin/../import/std/sumtype.d(418): Error: template instance `DeducedParameterType!(inout(SubCommand))` does not match template declaration `DeducedParameterType(T)` /home/luis/.local/bin/../import/std/sumtype.d(418): Error: template instance `DeducedParameterType!(inout(Unknown))` does not match template declaration `DeducedParameterType(T)` /home/luis/.local/bin/../import/std/sumtype.d(418): Error: template instance `DeducedParameterType!(inout(Argument))` does not match template declaration `DeducedParameterType(T)` /home/luis/.local/bin/../import/std/sumtype.d(418): Error: template instance `DeducedParameterType!(inout(SubCommand))` does not match template declaration `DeducedParameterType(T)` /home/luis/.local/bin/../import/std/sumtype.d(418): Error: template instance `DeducedParameterType!(inout(Unknown))` does not match template declaration `DeducedParameterType(T)` /home/luis/.local/bin/../import/std/sumtype.d(418): Error: template instance `DeducedParameterType!(inout(Argument))` does not match template declaration `DeducedParameterType(T)` /home/luis/.local/bin/../import/std/sumtype.d(418): Error: template instance `DeducedParameterType!(inout(SubCommand))` does not match template declaration `DeducedParameterType(T)` /home/luis/.local/bin/../import/std/sumtype.d(418): Error: template instance `DeducedParameterType!(inout(Unknown))` does not match template declaration `DeducedParameterType(T)` /home/luis/.local/bin/../import/std/sumtype.d(418): Error: template instance `DeducedParameterType!(inout(Argument))` does not match template declaration `DeducedParameterType(T)` /home/luis/.local/bin/../import/std/sumtype.d(418): Error: template instance `DeducedParameterType!(inout(SubCommand))` does not match template declaration `DeducedParameterType(T)` /home/luis/.local/bin/../import/std/sumtype.d(418): Error: template instance `DeducedParameterType!(inout(Unknown))` does not match template declaration `DeducedParameterType(T)` /home/luis/.local/bin/../import/std/sumtype.d(418): Error: template instance `DeducedParameterType!(inout(Argument))` does not match template declaration `DeducedParameterType(T)` /home/luis/.local/bin/../import/std/sumtype.d(418): Error: template instance `DeducedParameterType!(inout(SubCommand))` does not match template declaration `DeducedParameterType(T)` /home/luis/.local/bin/../import/std/sumtype.d(418): Error: template instance `DeducedParameterType!(inout(Unknown))` does not match template declaration `DeducedParameterType(T)` /home/luis/.local/bin/../import/std/sumtype.d(418): Error: template instance `DeducedParameterType!(inout(Argument))` does not match template declaration `DeducedParameterType(T)` /home/luis/.local/bin/../import/std/sumtype.d(418): Error: template instance `DeducedParameterType!(inout(SubCommand))` does not match template declaration `DeducedParameterType(T)` /home/luis/.local/bin/../import/std/sumtype.d(418): Error: template instance `DeducedParameterType!(inout(Unknown))` does not match template declaration `DeducedParameterType(T)` /home/luis/.local/bin/../import/std/sumtype.d(418): Error: template instance `DeducedParameterType!(inout(Argument))` does not match template declaration `DeducedParameterType(T)` ``` Turns out `DeducedParameterType` doesn't accept aliased types. Ultimately this should be a compiler issue, in my understanding of the language spec, as T and alias T shouldn't differ for types, but somehow it does. Making `DeducedParameterType` accepting aliased types, works.

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