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_1.nim

@@ -0,0 +1,17 @@
+discard """
+errormsg: "'bar' doesn't have a concrete type, due to unspecified generic parameters."
+line: 16
+"""
+
+proc foo[T]() =
+  var y1 = foo[string]
+  var y2 = foo[T]
+
+proc bar[T]() =
+  let x = 0
+
+let good1 = foo[int]
+let good2 = bar[int]
+
+let err = bar
+

tests/errmsgs/t5167_2.nim

@@ -0,0 +1,12 @@
+discard """
+cmd: "nim c --threads:on $file"
+errormsg: "'threadFunc' doesn't have a concrete type, due to unspecified generic parameters."
+line: 11
+"""
+
+proc threadFunc[T]() {.thread.} =
+  let x = 0
+
+var thr: Thread[void]
+thr.createThread(threadFunc)
+

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
+

tests/errmsgs/t5167_4.nim

@@ -0,0 +1,20 @@
+discard """
+errormsg: "type mismatch: got (proc [*missing parameters*](x: int) | proc (x: string){.gcsafe, locks: 0.})"
+line: 19
+"""
+
+type
+  TGeneric[T] = object
+    x: int
+
+proc foo[B](x: int) =
+  echo "foo1"
+
+proc foo(x: string) =
+  echo "foo2"
+
+proc bar(x: proc (x: int)) =
+  echo "bar"
+
+bar foo
+

tests/errmsgs/t5167_5.nim

@@ -0,0 +1,25 @@
+discard """
+cmd: "nim check $file"
+errormsg: "'m' has unspecified generic parameters"
+nimout: '''
+t5167_5.nim(20, 9) Error: 't' has unspecified generic parameters
+t5167_5.nim(21, 5) Error: 't' has unspecified generic parameters
+t5167_5.nim(23, 9) Error: 'm' has unspecified generic parameters
+t5167_5.nim(24, 5) Error: 'm' has unspecified generic parameters
+'''
+"""
+
+template t[B]() =
+  echo "foo1"
+
+macro m[T]: stmt = nil
+
+proc bar(x: proc (x: int)) =
+  echo "bar"
+
+let x = t
+bar t
+
+let y = m
+bar m
+