fixes another regression

tests/generics/tspecialized_procvar.nim

@@ -0,0 +1,17 @@
+discard """
+  output: '''concrete 88'''
+"""
+
+# Another regression triggered by changed closure computations:
+
+proc foo[T](x: proc(): T) =
+  echo "generic ", x()
+
+proc foo(x: proc(): int) =
+  echo "concrete ", x()
+
+# note the following 'proc' is not .closure!
+foo(proc (): auto {.nimcall.} = 88)
+
+# bug #3499 last snippet fixed
+# bug 705  last snippet fixed