don't stability-check macros in the same crate

Author: abonander

src/libsyntax/ext/base.rs

@@ -671,6 +671,7 @@ pub struct ExpansionData {
     pub depth: usize,
     pub module: Rc<ModuleData>,
     pub directory_ownership: DirectoryOwnership,
+    pub crate_span: Option<Span>,
 }
 
 /// One of these is made during expansion and incrementally updated as we go;
@@ -702,6 +703,7 @@ impl<'a> ExtCtxt<'a> {
                 depth: 0,
                 module: Rc::new(ModuleData { mod_path: Vec::new(), directory: PathBuf::new() }),
                 directory_ownership: DirectoryOwnership::Owned { relative: None },
+                crate_span: None,
             },
             expansions: HashMap::new(),
         }

src/libsyntax/ext/expand.rs

@@ -229,6 +229,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
         module.directory.pop();
         self.cx.root_path = module.directory.clone();
         self.cx.current_expansion.module = Rc::new(module);
+        self.cx.current_expansion.crate_span = Some(krate.span);
 
         let orig_mod_span = krate.module.inner;
 
@@ -540,9 +541,10 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
 
             // feature-gate the macro invocation
             if let Some((feature, issue)) = unstable_feature {
-                // only if the outer span doesn't allow unstable invocations
-                // TODO: compare crates of span and def_site_span (can't figure out how)
-                if !span.allows_unstable() && self_.cx.ecfg.features.map_or(true, |feats| {
+                let crate_span = self_.cx.current_expansion.crate_span.unwrap();
+                // don't stability-check macros in the same crate
+                if !crate_span.contains(def_site_span)
+                    && !span.allows_unstable() && self_.cx.ecfg.features.map_or(true, |feats| {
                     // macro features will count as lib features
                     !feats.declared_lib_features.iter().any(|&(feat, _)| feat == feature)
                 }) {