Fixes #5167 and related problems (#5475)

This commit returns to a bit less strict checking of the number
of macro arguments, because some old immediate macros rely on a
behavior where even the arity of the macro is not being checked.

It may be better if such macros are just declared to use varargs[expr],
but this remains for another day.

tests/errmsgs/t5167_3.nim

@@ -0,0 +1,25 @@
+discard """
+cmd: "nim c --threads:on $file"
+errormsg: "type mismatch"
+line: 24
+"""
+
+type
+  TGeneric[T] = object
+    x: int
+
+proc foo1[A, B, C, D](x: proc (a: A, b: B, c: C, d: D)) =
+  echo "foo1"
+
+proc foo2(x: proc(x: int)) =
+  echo "foo2"
+
+# The goal of this test is to verify that none of the generic parameters of the
+# proc will be marked as unused. The error message should be "type mismatch" instead
+# of "'bar' doesn't have a concrete type, due to unspecified generic parameters".
+proc bar[A, B, C, D](x: A, y: seq[B], z: array[4, TGeneric[C]], r: TGeneric[D]) =
+  echo "bar"
+
+foo1[int, seq[int], array[4, TGeneric[float]], TGeneric[string]] bar
+foo2 bar
+