remove `prev == nil` requirement for typedesc params as type nodes (#24206)

fixes #24203

`semTypeNode` is called twice for RHS'es of type sections,
[here](https://github.com/nim-lang/Nim/blob/b0e6d28782ce8c3d8e0b4a64e01f21d6f900648f/compiler/semstmts.nim#L1612)
and
[here](https://github.com/nim-lang/Nim/blob/b0e6d28782ce8c3d8e0b4a64e01f21d6f900648f/compiler/semstmts.nim#L1646).
Each time `prev` is `s.typ`, but the assertion expects `prev == nil`
which is false since `s.typ` is not nil the second time. To fix this,
the `prev == nil` part of the assertion is removed.

The reason this only happens for types like `seq[int]`, `(int, int)` etc
is because they don't have syms: `semTypeIdent` attempts to directly
[replace the typedesc param
itself](https://github.com/nim-lang/Nim/blob/b0e6d28782ce8c3d8e0b4a64e01f21d6f900648f/compiler/semtypes.nim#L1916)
with the sym of the base type of the resolved typedesc type if it
exists, which means `semTypeNode` doesn't receive the typedesc param sym
to perform the assert.

0 files changed, 0 insertions, 0 deletions