1 files changed, 56 insertions, 0 deletions
diff --git a/tests/ui/cfg/assume-incomplete-release/auxiliary/ver-cfg-rel.rs b/tests/ui/cfg/assume-incomplete-release/auxiliary/ver-cfg-rel.rs
new file mode 100644
index 000000000..067c620f5
--- /dev/null
+++ b/tests/ui/cfg/assume-incomplete-release/auxiliary/ver-cfg-rel.rs
@@ -0,0 +1,56 @@
+// force-host
+// no-prefer-dynamic
+
+#![crate_type = "proc-macro"]
+
+extern crate proc_macro;
+use proc_macro::{TokenStream, TokenTree as Tt};
+use std::str::FromStr;
+
+// String containing the current version number of the tip, i.e. "1.41.2"
+static VERSION_NUMBER: &str = include_str!("../../../../../src/version");
+
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
+struct Version {
+    major: i16,
+    minor: i16,
+    patch: i16,
+}
+
+fn parse_version(s: &str) -> Option<Version> {
+    let mut digits = s.splitn(3, '.');
+    let major = digits.next()?.parse().ok()?;
+    let minor = digits.next()?.parse().ok()?;
+    let patch = digits.next().unwrap_or("0").trim().parse().ok()?;
+    Some(Version { major, minor, patch })
+}
+
+#[proc_macro_attribute]
+/// Emits a #[cfg(version)] relative to the current one, so passing
+/// -1 as argument on compiler 1.50 will emit #[cfg(version("1.49.0"))],
+/// while 1 will emit #[cfg(version("1.51.0"))]
+pub fn ver_cfg_rel(attr: TokenStream, input: TokenStream) -> TokenStream {
+    let mut v_rel = None;
+    for a in attr.into_iter() {
+        match a {
+            Tt::Literal(l) => {
+                let mut s = l.to_string();
+                let s = s.trim_matches('"');
+                let v: i16 = s.parse().unwrap();
+                v_rel = Some(v);
+                break;
+            },
+            _ => panic!("{:?}", a),
+        }
+    }
+    let v_rel = v_rel.unwrap();
+
+    let mut v = parse_version(VERSION_NUMBER).unwrap();
+    v.minor += v_rel;
+
+    let attr_str = format!("#[cfg(version(\"{}.{}.{}\"))]", v.major, v.minor, v.patch);
+    let mut res = Vec::<Tt>::new();
+    res.extend(TokenStream::from_str(&attr_str).unwrap().into_iter());
+    res.extend(input.into_iter());
+    res.into_iter().collect()
+}