multiple-value type assertion stupidity

[Nikodemus Siivola]

(compile nil `(lambda (s) (the (unsigned-byte 8) (read-byte s))))

gives

; (THE (UNSIGNED-BYTE 8) (READ-BYTE S))
;
; note: type assertion too complex to check:
; (VALUES (UNSIGNED-BYTE 8) &REST T).

This is silly.

While (THE X (FOO)) is too complex to check when the number of values returned by FOO is in doubt, here we know that READ-BYTE will only return a single value -- and hence we could simplify the assertion to (VALUES (UNSIGNED-BYTE 8) &OPTIONAL).

[Nikodemus Siivola (nikodemus)]

I misdiagnosed this initially.

The issue is really that READ-BYTE has been declared NOTINLINE, and NOTLINE currently has the side-effect of stopping the compiler from utilizing the proclaimed FTYPE.

[Nikodemus Siivola (nikodemus)]

In 1.0.43.39.