ambiguous identifier resolution (#23123)

fixes #23002, fixes #22841, refs comments in #23097

When an identifier is ambiguous in scope (i.e. multiple imports contain
symbols with the same name), attempt resolving it through type inference
(by creating a symchoice). To do this efficiently, `qualifiedLookUp` had
to be broken up so that `semExpr` can access the ambiguous candidates
directly (now obtained directly via `lookUpCandidates`).

This fixes the linked issues, but an example like:

```nim
let on = 123

{.warning[ProveInit]: on.}
```

will still fail, since `on` is unambiguously the local `let` symbol here
(this is also true for `proc on` but `proc` symbols generate symchoices
anyway).

Type symbols are not considered to not confuse the type inference. This
includes the change in sigmatch, up to this point symchoices with
nonoverloadable symbols could be created, they just wouldn't be
considered during disambiguation. Now every proper symbol except types
are considered in disambiguation, so the correct symbols must be picked
during the creation of the symchoice node. I remember there being a
violating case of this in the compiler, but this was very likely fixed
by excluding type symbols as CI seems to have found no issues.

The pure enum ambiguity test was disabled because ambiguous pure enums
now behave like overloadable enums with this behavior, so we get a
longer error message for `echo amb` like `type mismatch: got <MyEnum |
OtherEnum> but expected T`

1 files changed, 1 insertions, 1 deletions

diff --git a/tests/lookups/tambsym3.nim b/tests/lookups/tambsym3.nim
index 6e7589cd8..6bbebca10 100644
--- a/tests/lookups/tambsym3.nim
+++ b/tests/lookups/tambsym3.nim
@@ -1,5 +1,5 @@
 discard """
-  errormsg: "ambiguous identifier 'mDec' -- use one of the following:"
+  errormsg: "ambiguous identifier: 'mDec' -- use one of the following:"
   file: "tambsym3.nim"
   line: 11
 """