fixes #2401

compiler/ccgexprs.nim

@@ -1962,7 +1962,7 @@ proc expr(p: BProc, n: PNode, d: var TLoc) =
     var sym = n.sym
     case sym.kind
     of skMethod:
-      if sym.getBody.kind == nkEmpty or sfDispatcher in sym.flags:
+      if {sfDispatcher, sfForward} * sym.flags != {}:
         # we cannot produce code for the dispatcher yet:
         fillProcLoc(sym)
         genProcPrototype(p.module, sym)

tests/method/temptybody.nim

@@ -0,0 +1,11 @@
+# bug #2401
+
+type MyClass = ref object of RootObj
+
+method HelloWorld*(obj: MyClass) =
+  when defined(myPragma):
+    echo("Hello World")
+  # discard # with this line enabled it works
+
+var obj = MyClass()
+obj.HelloWorld()