Correctly process the concretize attribute within cfg_attr

The concretize attribute isn't processed as a normal Rust attribute.
Instead, Mockall processes it as text.  So we need to process any
cfg_attr directive ourselves.  Rather than attempt to evaluate the
conditional, just assume that it's true.  By far the most common use
case will be `cfg_attr(test, concretize)`.

Fixes #427

mockall/tests/cfg_attr_concretize.rs

@@ -0,0 +1,26 @@
+// vim: tw=80
+//! #[concretize] can be used inside of #[cfg_attr()]`
+#![deny(warnings)]
+
+use std::path::{Path, PathBuf};
+
+use mockall::{automock, concretize};
+
+#[automock]
+trait Foo {
+ #[cfg_attr(not(target_os = "ia64-unknown-multics"), concretize)]
+ fn foo<P: AsRef<Path>>(&self, p: P);
+}
+
+
+#[test]
+fn withf() {
+ let mut foo = MockFoo::new();
+ foo.expect_foo()
+ .withf(|p| p.as_ref() == Path::new("/tmp"))
+ .times(3)
+ .return_const(());
+ foo.foo(Path::new("/tmp"));
+ foo.foo(PathBuf::from(Path::new("/tmp")));
+ foo.foo("/tmp");
+}

mockall_derive/src/lib.rs

@@ -754,6 +754,11 @@ impl<'a> AttrFormatter<'a> {
  } else if *i.as_ref().unwrap() == "concretize" {
  // Internally used attribute. Never emit.
  false
+ } else if *i.as_ref().unwrap() == "cfg_attr" &&
+ attr.tokens.to_string().contains("concretize")
+ {
+ // Internally used attribute. Never emit.
+ false
  } else {
  true
  }

mockall_derive/src/mock_function.rs

@@ -168,7 +168,13 @@ impl<'a> Builder<'a> {
  .any(|attr|
  attr.path.segments.last()
  .map(|ps| ps.ident == "concretize")
- .unwrap_or(false)
+ .unwrap_or(false) ||
+ (
+ attr.path.segments.last()
+ .map(|ps| ps.ident == "cfg_attr")
+ .unwrap_or(false) &&
+ attr.tokens.to_string().contains("concretize")
+ )
  ) {
  self.concretize = true;
  }