Impossible to use TypeRepr#memberType

[rskfocus]

Compiler version

3.1.3

Minimized code

/* this definitions are supposed to be equal, isn't it? */
val repr: TypeRepr = ...
val alsoRepr: TypeRepr = repr.memberType(repr.typeSymbol)

/* but this assertion is failing! */
assert(repr =:= alsoRepr)

/* and even trying to `show` it is impossible */
alsoRepr.show // scala.MatchError: ClassInfo(ThisType(...))

Expectation

My macro uses Symbol#tree in a few places and it works, but I'm noticed that there is a warning in documentation that suggest replacing it with tp.memberType(symbol).

Not only it doesn't work, but it is quite confusing what tp should be.

Why isn't it a static method such as TypeRepr.memberType(symbol)?

[rochala]

Related to #13319
#15159