move feature_gate to libsyntax

Author: Nick Cameron

src/librustc/driver/driver.rs

@@ -13,7 +13,6 @@ use back::link;
 use back::write;
 use driver::session::Session;
 use driver::config;
-use front;
 use lint;
 use llvm::{ContextRef, ModuleRef};
 use metadata::common::LinkMeta;
@@ -194,8 +193,20 @@ pub fn phase_2_configure_and_expand(sess: &Session,
     *sess.crate_metadata.borrow_mut() =
         collect_crate_metadata(sess, krate.attrs.as_slice());
 
-    time(time_passes, "gated feature checking", (), |_|
-         front::feature_gate::check_crate(sess, &krate));
+    time(time_passes, "gated feature checking", (), |_| {
+        let (features, unknown_features) =
+            syntax::feature_gate::check_crate(&sess.parse_sess.span_diagnostic, &krate);
+
+        for uf in unknown_features.iter() {
+            sess.add_lint(lint::builtin::UNKNOWN_FEATURES,
+                          ast::CRATE_NODE_ID,
+                          *uf,
+                          "unknown feature".to_string());
+        }
+
+        sess.abort_if_errors();
+        *sess.features.borrow_mut() = features;
+    });
 
     let any_exe = sess.crate_types.borrow().iter().any(|ty| {
         *ty == config::CrateTypeExecutable
@@ -225,7 +236,7 @@ pub fn phase_2_configure_and_expand(sess: &Session,
     let mut registry = Registry::new(&krate);
 
     time(time_passes, "plugin registration", (), |_| {
-        if sess.features.rustc_diagnostic_macros.get() {
+        if sess.features.borrow().rustc_diagnostic_macros {
             registry.register_macro("__diagnostic_used",
                 diagnostics::plugin::expand_diagnostic_used);
             registry.register_macro("__register_diagnostic",
@@ -277,7 +288,7 @@ pub fn phase_2_configure_and_expand(sess: &Session,
                 os::setenv("PATH", os::join_paths(new_path.as_slice()).unwrap());
             }
             let cfg = syntax::ext::expand::ExpansionConfig {
-                deriving_hash_type_parameter: sess.features.default_type_params.get(),
+                deriving_hash_type_parameter: sess.features.borrow().default_type_params,
                 crate_name: crate_name.to_string(),
             };
             let ret = syntax::ext::expand::expand_crate(&sess.parse_sess,

src/librustc/driver/session.rs

@@ -11,7 +11,6 @@
 
 use driver::config;
 use driver::driver;
-use front;
 use metadata::cstore::CStore;
 use metadata::filesearch;
 use lint;
@@ -21,6 +20,7 @@ use syntax::ast::NodeId;
 use syntax::codemap::Span;
 use syntax::diagnostic;
 use syntax::diagnostics;
+use syntax::feature_gate;
 use syntax::parse;
 use syntax::parse::token;
 use syntax::parse::ParseSess;
@@ -49,7 +49,7 @@ pub struct Session {
     pub lints: RefCell<NodeMap<Vec<(lint::LintId, codemap::Span, String)>>>,
     pub crate_types: RefCell<Vec<config::CrateType>>,
     pub crate_metadata: RefCell<Vec<String>>,
-    pub features: front::feature_gate::Features,
+    pub features: RefCell<feature_gate::Features>,
 
     /// The maximum recursion limit for potentially infinitely recursive
     /// operations such as auto-dereference and monomorphization.
@@ -245,7 +245,7 @@ pub fn build_session_(sopts: config::Options,
         lints: RefCell::new(NodeMap::new()),
         crate_types: RefCell::new(Vec::new()),
         crate_metadata: RefCell::new(Vec::new()),
-        features: front::feature_gate::Features::new(),
+        features: RefCell::new(feature_gate::Features::new()),
         recursion_limit: Cell::new(64),
     };
 

src/librustc/lib.rs

@@ -116,10 +116,6 @@ pub mod middle {
     pub mod weak_lang_items;
 }
 
-pub mod front {
-    pub mod feature_gate;
-}
-
 pub mod metadata;
 
 pub mod driver;

src/librustc/middle/resolve.rs

@@ -2811,7 +2811,7 @@ impl<'a> Resolver<'a> {
                                     import_span: Span,
                                     name: Name,
                                     namespace: Namespace) {
-        if self.session.features.import_shadowing.get() {
+        if self.session.features.borrow().import_shadowing {
             return
         }
 
@@ -2837,7 +2837,7 @@ impl<'a> Resolver<'a> {
                                                      &mut ImportResolution,
                                                      import_span: Span,
                                                      name: Name) {
-        if self.session.features.import_shadowing.get() {
+        if self.session.features.borrow().import_shadowing {
             return
         }
 
@@ -2919,7 +2919,7 @@ impl<'a> Resolver<'a> {
                                                    module: &Module,
                                                    name: Name,
                                                    span: Span) {
-        if self.session.features.import_shadowing.get() {
+        if self.session.features.borrow().import_shadowing {
             return
         }
 
@@ -2937,7 +2937,7 @@ impl<'a> Resolver<'a> {
                                                              module: &Module,
                                                              name: Name,
                                                              span: Span) {
-        if self.session.features.import_shadowing.get() {
+        if self.session.features.borrow().import_shadowing {
             return
         }
 

src/librustc/middle/typeck/astconv.rs

@@ -235,7 +235,7 @@ fn ast_path_substs<'tcx, AC: AstConv<'tcx>, RS: RegionScope>(
     }
 
     if supplied_ty_param_count > required_ty_param_count
-        && !this.tcx().sess.features.default_type_params.get() {
+        && !this.tcx().sess.features.borrow().default_type_params {
         span_err!(this.tcx().sess, path.span, E0108,
             "default type parameters are experimental and possibly buggy");
         span_note!(this.tcx().sess, path.span,

src/librustc/middle/typeck/check/mod.rs

@@ -2131,7 +2131,7 @@ fn try_overloaded_call(fcx: &FnCtxt,
         fcx.inh.method_map.borrow_mut().insert(method_call, method_callee);
         write_call(fcx, call_expression, output_type);
 
-        if !fcx.tcx().sess.features.overloaded_calls.get() {
+        if !fcx.tcx().sess.features.borrow().overloaded_calls {
             span_err!(fcx.tcx().sess, call_expression.span, E0056,
                 "overloaded calls are experimental");
             span_note!(fcx.tcx().sess, call_expression.span,

src/librustc/front/feature_gate.rs renamed to src/libsyntax/feature_gate.rs

@@ -18,21 +18,17 @@
 //! Features are enabled in programs via the crate-level attributes of
 //! `#![feature(...)]` with a comma-separated list of features.
 
-use lint;
+use abi::RustIntrinsic;
+use ast::NodeId;
+use ast;
+use attr;
+use attr::AttrMetaMethods;
+use codemap::Span;
+use diagnostic::SpanHandler;
+use visit;
+use visit::Visitor;
+use parse::token;
 
-use syntax::abi::RustIntrinsic;
-use syntax::ast::NodeId;
-use syntax::ast;
-use syntax::attr;
-use syntax::attr::AttrMetaMethods;
-use syntax::codemap::Span;
-use syntax::visit;
-use syntax::visit::Visitor;
-use syntax::parse::token;
-
-use driver::session::Session;
-
-use std::cell::Cell;
 use std::slice;
 
 /// This is a list of all known features since the beginning of time. This list
@@ -99,35 +95,35 @@ enum Status {
 
 /// A set of features to be used by later passes.
 pub struct Features {
-    pub default_type_params: Cell<bool>,
-    pub overloaded_calls: Cell<bool>,
-    pub rustc_diagnostic_macros: Cell<bool>,
-    pub import_shadowing: Cell<bool>,
+    pub default_type_params: bool,
+    pub overloaded_calls: bool,
+    pub rustc_diagnostic_macros: bool,
+    pub import_shadowing: bool,
 }
 
 impl Features {
     pub fn new() -> Features {
         Features {
-            default_type_params: Cell::new(false),
-            overloaded_calls: Cell::new(false),
-            rustc_diagnostic_macros: Cell::new(false),
-            import_shadowing: Cell::new(false),
+            default_type_params: false,
+            overloaded_calls: false,
+            rustc_diagnostic_macros: false,
+            import_shadowing: false,
         }
     }
 }
 
 struct Context<'a> {
     features: Vec<&'static str>,
-    sess: &'a Session,
+    span_handler: &'a SpanHandler,
 }
 
 impl<'a> Context<'a> {
     fn gate_feature(&self, feature: &str, span: Span, explain: &str) {
         if !self.has_feature(feature) {
-            self.sess.span_err(span, explain);
-            self.sess.span_note(span, format!("add #![feature({})] to the \
-                                               crate attributes to enable",
-                                              feature).as_slice());
+            self.span_handler.span_err(span, explain);
+            self.span_handler.span_note(span, format!("add #![feature({})] to the \
+                                                       crate attributes to enable",
+                                                      feature).as_slice());
         }
     }
 
@@ -404,48 +400,47 @@ impl<'a, 'v> Visitor<'v> for Context<'a> {
     }
 }
 
-pub fn check_crate(sess: &Session, krate: &ast::Crate) {
+pub fn check_crate(span_handler: &SpanHandler, krate: &ast::Crate) -> (Features, Vec<Span>) {
     let mut cx = Context {
         features: Vec::new(),
-        sess: sess,
+        span_handler: span_handler,
     };
 
+    let mut unknown_features = Vec::new();
+
     for attr in krate.attrs.iter() {
         if !attr.check_name("feature") {
             continue
         }
 
         match attr.meta_item_list() {
             None => {
-                sess.span_err(attr.span, "malformed feature attribute, \
-                                          expected #![feature(...)]");
+                span_handler.span_err(attr.span, "malformed feature attribute, \
+                                                  expected #![feature(...)]");
             }
             Some(list) => {
                 for mi in list.iter() {
                     let name = match mi.node {
                         ast::MetaWord(ref word) => (*word).clone(),
                         _ => {
-                            sess.span_err(mi.span,
-                                          "malformed feature, expected just \
-                                           one word");
+                            span_handler.span_err(mi.span,
+                                                  "malformed feature, expected just \
+                                                   one word");
                             continue
                         }
                     };
                     match KNOWN_FEATURES.iter()
                                         .find(|& &(n, _)| name.equiv(&n)) {
                         Some(&(name, Active)) => { cx.features.push(name); }
                         Some(&(_, Removed)) => {
-                            sess.span_err(mi.span, "feature has been removed");
+                            span_handler.span_err(mi.span, "feature has been removed");
                         }
                         Some(&(_, Accepted)) => {
-                            sess.span_warn(mi.span, "feature has been added to Rust, \
-                                                     directive not necessary");
+                            span_handler.span_warn(mi.span, "feature has been added to Rust, \
+                                                             directive not necessary");
                         }
                         None => {
-                            sess.add_lint(lint::builtin::UNKNOWN_FEATURES,
-                                          ast::CRATE_NODE_ID,
-                                          mi.span,
-                                          "unknown feature".to_string());
+                            unknown_features.push(mi.span);
                         }
                     }
                 }
@@ -455,11 +450,12 @@ pub fn check_crate(sess: &Session, krate: &ast::Crate) {
 
     visit::walk_crate(&mut cx, krate);
 
-    sess.abort_if_errors();
-
-    sess.features.default_type_params.set(cx.has_feature("default_type_params"));
-    sess.features.overloaded_calls.set(cx.has_feature("overloaded_calls"));
-    sess.features.rustc_diagnostic_macros.set(cx.has_feature("rustc_diagnostic_macros"));
-    sess.features.import_shadowing.set(cx.has_feature("import_shadowing"));
+    (Features {
+        default_type_params: cx.has_feature("default_type_params"),
+        overloaded_calls: cx.has_feature("overloaded_calls"),
+        rustc_diagnostic_macros: cx.has_feature("rustc_diagnostic_macros"),
+        import_shadowing: cx.has_feature("import_shadowing"),
+    },
+    unknown_features)
 }
 

src/libsyntax/lib.rs

@@ -62,6 +62,7 @@ pub mod codemap;
 pub mod config;
 pub mod crateid;
 pub mod diagnostic;
+pub mod feature_gate;
 pub mod fold;
 pub mod owned_slice;
 pub mod parse;