Fix #22826: Don't skip generic instances in type comparison (#22828)

Close #22826

I am not sure why this code skips generic insts, so letting CI tell me.
Update: It has told me nothing. Maybe someone knows during review.

Issue itself seems to be that the generic instance is skipped thus it
ends up being just `float` which makes it use the wrong generic instance
of the proc because it matches the one in cache

---------

Co-authored-by: SirOlaf <>

compiler/types.nim

@@ -1202,12 +1202,12 @@ proc sameTypeAux(x, y: PType, c: var TSameTypeClosure): bool =
       if containsOrIncl(c, a, b): return true
 
   if x == y: return true
-  var a = skipTypes(x, {tyGenericInst, tyAlias})
+  var a = skipTypes(x, {tyAlias})
   while a.kind == tyUserTypeClass and tfResolved in a.flags:
-    a = skipTypes(a[^1], {tyGenericInst, tyAlias})
-  var b = skipTypes(y, {tyGenericInst, tyAlias})
+    a = skipTypes(a[^1], {tyAlias})
+  var b = skipTypes(y, {tyAlias})
   while b.kind == tyUserTypeClass and tfResolved in b.flags:
-    b = skipTypes(b[^1], {tyGenericInst, tyAlias})
+    b = skipTypes(b[^1], {tyAlias})
   assert(a != nil)
   assert(b != nil)
   if a.kind != b.kind:

tests/generics/t22826.nim

@@ -0,0 +1,8 @@
+import std/tables
+
+var a: Table[string, float]
+
+type Value*[T] = object
+  table: Table[string, Value[T]]
+
+discard toTable({"a": Value[float]()})