add workaround & explanation

compiler/sigmatch.nim

@@ -2429,7 +2429,13 @@ proc paramTypesMatchAux(m: var TCandidate, f, a: PType,
       result = arg
     elif skipTypes(arg.typ, abstractVar-{tyTypeDesc}).kind == tyTuple or cmpInheritancePenalty(oldInheritancePenalty, m.inheritancePenalty) > 0:
       result = implicitConv(nkHiddenSubConv, f, arg, m, c)
-    elif arg.typ.isEmptyContainer or arg.typ.isIntLit:
+    elif arg.typ.isEmptyContainer or
+        # XXX `and not m.isNoCall` is a workaround
+        # passing an int to generic types converts it to the type `int`
+        # but this isn't done for int literal types, so we preserve the type
+        # i.e. works: `type Foo[T] = array[T, int]; var x: Foo[3]` (see t12938, t14193)
+        # doesn't work: `proc foo[T](): array[T, int] = ...; foo[3]()` (see #23204)
+        (arg.typ.isIntLit and not m.isNoCall):
       result = arg.copyTree
       result.typ = getInstantiatedType(c, arg, m, f).skipTypes({tySink})
     else:

tests/generics/t14193.nim

@@ -1,5 +1,5 @@
 type
-  Task*[N: int] = object
+  Task*[N: int] = object # XXX this shouldn't work, should be `static int`
     env*: array[N, byte]
 
 var task14193: Task[20]