Feature gate clean

src/librustc_driver/driver.rs

@@ -512,19 +512,13 @@ pub fn phase_2_configure_and_expand(sess: &Session,
         middle::recursion_limit::update_recursion_limit(sess, &krate);
     });
 
-    time(time_passes, "gated macro checking", || {
-        sess.track_errors(|| {
-            let features =
-              syntax::feature_gate::check_crate_macros(sess.codemap(),
-                                                       &sess.parse_sess.span_diagnostic,
-                                                       &krate);
-
-            // these need to be set "early" so that expansion sees `quote` if enabled.
-            *sess.features.borrow_mut() = features;
-        })
+    // these need to be set "early" so that expansion sees `quote` if enabled.
+    sess.track_errors(|| {
+        *sess.features.borrow_mut() =
+            syntax::feature_gate::get_features(&sess.parse_sess.span_diagnostic,
+                                               &krate);
     })?;
 
-
     krate = time(time_passes, "crate injection", || {
         syntax::std_inject::maybe_inject_crates_ref(krate, sess.opts.alt_std_name.clone())
     });

src/librustc_plugin/load.rs

@@ -51,27 +51,32 @@ pub fn load_plugins(sess: &Session,
                     addl_plugins: Option<Vec<String>>) -> Vec<PluginRegistrar> {
     let mut loader = PluginLoader::new(sess, cstore, crate_name);
 
-    for attr in &krate.attrs {
-        if !attr.check_name("plugin") {
-            continue;
-        }
-
-        let plugins = match attr.meta_item_list() {
-            Some(xs) => xs,
-            None => {
-                call_malformed_plugin_attribute(sess, attr.span);
+    // do not report any error now. since crate attributes are
+    // not touched by expansion, every use of plugin without
+    // the feature enabled will result in an error later...
+    if sess.features.borrow().plugin {
+        for attr in &krate.attrs {
+            if !attr.check_name("plugin") {
                 continue;
             }
-        };
 
-        for plugin in plugins {
-            if plugin.value_str().is_some() {
-                call_malformed_plugin_attribute(sess, attr.span);
-                continue;
+            let plugins = match attr.meta_item_list() {
+                Some(xs) => xs,
+                None => {
+                    call_malformed_plugin_attribute(sess, attr.span);
+                    continue;
+                }
+            };
+
+            for plugin in plugins {
+                if plugin.value_str().is_some() {
+                    call_malformed_plugin_attribute(sess, attr.span);
+                    continue;
+                }
+
+                let args = plugin.meta_item_list().map(ToOwned::to_owned).unwrap_or_default();
+                loader.load_plugin(plugin.span, &plugin.name(), args);
             }
-
-            let args = plugin.meta_item_list().map(ToOwned::to_owned).unwrap_or_default();
-            loader.load_plugin(plugin.span, &plugin.name(), args);
         }
     }
 

src/libsyntax/ext/expand.rs

@@ -35,13 +35,26 @@ use std_inject;
 use std::collections::HashSet;
 use std::env;
 
+// this function is called to detect use of feature-gated or invalid attributes
+// on macro invoations since they will not be detected after macro expansion
+fn check_attributes(attrs: &[ast::Attribute], fld: &MacroExpander) {
+    for attr in attrs.iter() {
+        feature_gate::check_attribute(&attr, &fld.cx.parse_sess.span_diagnostic,
+                                      &fld.cx.parse_sess.codemap(),
+                                      &fld.cx.ecfg.features.unwrap());
+    }
+}
+
 pub fn expand_expr(e: P<ast::Expr>, fld: &mut MacroExpander) -> P<ast::Expr> {
     let expr_span = e.span;
     return e.and_then(|ast::Expr {id, node, span, attrs}| match node {
 
         // expr_mac should really be expr_ext or something; it's the
         // entry-point for all syntax extensions.
         ast::ExprKind::Mac(mac) => {
+            if let Some(ref attrs) = attrs {
+                check_attributes(attrs, fld);
+            }
 
             // Assert that we drop any macro attributes on the floor here
             drop(attrs);
@@ -70,10 +83,12 @@ pub fn expand_expr(e: P<ast::Expr>, fld: &mut MacroExpander) -> P<ast::Expr> {
 
         ast::ExprKind::InPlace(placer, value_expr) => {
             // Ensure feature-gate is enabled
-            feature_gate::check_for_placement_in(
-                fld.cx.ecfg.features,
-                &fld.cx.parse_sess.span_diagnostic,
-                expr_span);
+            if !fld.cx.ecfg.features.unwrap().placement_in_syntax {
+                feature_gate::emit_feature_err(
+                    &fld.cx.parse_sess.span_diagnostic, "placement_in_syntax", expr_span,
+                    feature_gate::GateIssue::Language, feature_gate::EXPLAIN_PLACEMENT_IN
+                );
+            }
 
             let placer = fld.fold_expr(placer);
             let value_expr = fld.fold_expr(value_expr);
@@ -367,6 +382,8 @@ pub fn expand_item_mac(it: P<ast::Item>,
         _ => fld.cx.span_bug(it.span, "invalid item macro invocation")
     });
 
+    check_attributes(&attrs, fld);
+
     let fm = fresh_mark();
     let items = {
         let expanded = match fld.cx.syntax_env.find(extname) {
@@ -441,18 +458,6 @@ pub fn expand_item_mac(it: P<ast::Item>,
                     let allow_internal_unstable = attr::contains_name(&attrs,
                                                                       "allow_internal_unstable");
 
-                    // ensure any #[allow_internal_unstable]s are
-                    // detected (including nested macro definitions
-                    // etc.)
-                    if allow_internal_unstable && !fld.cx.ecfg.enable_allow_internal_unstable() {
-                        feature_gate::emit_feature_err(
-                            &fld.cx.parse_sess.span_diagnostic,
-                            "allow_internal_unstable",
-                            span,
-                            feature_gate::GateIssue::Language,
-                            feature_gate::EXPLAIN_ALLOW_INTERNAL_UNSTABLE)
-                    }
-
                     let export = attr::contains_name(&attrs, "macro_export");
                     let def = ast::MacroDef {
                         ident: ident,
@@ -516,6 +521,10 @@ fn expand_stmt(stmt: Stmt, fld: &mut MacroExpander) -> SmallVector<Stmt> {
         _ => return expand_non_macro_stmt(stmt, fld)
     };
 
+    if let Some(ref attrs) = attrs {
+        check_attributes(attrs, fld);
+    }
+
     // Assert that we drop any macro attributes on the floor here
     drop(attrs);
 
@@ -1063,7 +1072,7 @@ fn expand_impl_item(ii: ast::ImplItem, fld: &mut MacroExpander)
             attrs: ii.attrs,
             vis: ii.vis,
             defaultness: ii.defaultness,
-            node: match ii.node  {
+            node: match ii.node {
                 ast::ImplItemKind::Method(sig, body) => {
                     let (sig, body) = expand_and_rename_method(sig, body, fld);
                     ast::ImplItemKind::Method(sig, body)
@@ -1072,13 +1081,11 @@ fn expand_impl_item(ii: ast::ImplItem, fld: &mut MacroExpander)
             },
             span: fld.new_span(ii.span)
         }),
-        ast::ImplItemKind::Macro(_) => {
-            let (span, mac) = match ii.node {
-                ast::ImplItemKind::Macro(mac) => (ii.span, mac),
-                _ => unreachable!()
-            };
+        ast::ImplItemKind::Macro(mac) => {
+            check_attributes(&ii.attrs, fld);
+
             let maybe_new_items =
-                expand_mac_invoc(mac, span,
+                expand_mac_invoc(mac, ii.span,
                                  |r| r.make_impl_items(),
                                  |meths, mark| meths.move_map(|m| mark_impl_item(m, mark)),
                                  fld);
@@ -1345,14 +1352,14 @@ impl<'feat> ExpansionConfig<'feat> {
     }
 
     feature_tests! {
-        fn enable_quotes = allow_quote,
-        fn enable_asm = allow_asm,
-        fn enable_log_syntax = allow_log_syntax,
-        fn enable_concat_idents = allow_concat_idents,
-        fn enable_trace_macros = allow_trace_macros,
+        fn enable_quotes = quote,
+        fn enable_asm = asm,
+        fn enable_log_syntax = log_syntax,
+        fn enable_concat_idents = concat_idents,
+        fn enable_trace_macros = trace_macros,
         fn enable_allow_internal_unstable = allow_internal_unstable,
-        fn enable_custom_derive = allow_custom_derive,
-        fn enable_pushpop_unsafe = allow_pushpop_unsafe,
+        fn enable_custom_derive = custom_derive,
+        fn enable_pushpop_unsafe = pushpop_unsafe,
     }
 }