Replace enum LintId with an extensible alternative

Author: Keegan McAllister

src/librustc/driver/config.rs

@@ -70,7 +70,8 @@ pub struct Options {
     pub gc: bool,
     pub optimize: OptLevel,
     pub debuginfo: DebugInfoLevel,
-    pub lint_opts: Vec<(lint::LintId, lint::Level)> ,
+    pub lint_opts: Vec<(String, lint::Level)>,
+    pub describe_lints: bool,
     pub output_types: Vec<back::link::OutputType> ,
     // This was mutable for rustpkg, which updates search paths based on the
     // parsed code. It remains mutable in case its replacements wants to use
@@ -104,6 +105,7 @@ pub fn basic_options() -> Options {
         optimize: No,
         debuginfo: NoDebugInfo,
         lint_opts: Vec::new(),
+        describe_lints: false,
         output_types: Vec::new(),
         addl_lib_search_paths: RefCell::new(HashSet::new()),
         maybe_sysroot: None,
@@ -585,30 +587,15 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
     let no_trans = matches.opt_present("no-trans");
     let no_analysis = matches.opt_present("no-analysis");
 
-    let lint_levels = [lint::Allow, lint::Warn,
-                       lint::Deny, lint::Forbid];
-    let mut lint_opts = Vec::new();
-    let lint_dict = lint::get_lint_dict();
-    for level in lint_levels.iter() {
-        let level_name = lint::level_to_str(*level);
-
-        let level_short = level_name.slice_chars(0, 1);
-        let level_short = level_short.to_ascii().to_upper().into_str();
-        let flags = matches.opt_strs(level_short.as_slice())
-                           .move_iter()
-                           .collect::<Vec<_>>()
-                           .append(matches.opt_strs(level_name).as_slice());
-        for lint_name in flags.iter() {
-            let lint_name = lint_name.replace("-", "_").into_string();
-            match lint_dict.find_equiv(&lint_name) {
-              None => {
-                early_error(format!("unknown {} flag: {}",
-                                    level_name,
-                                    lint_name).as_slice());
-              }
-              Some(lint) => {
-                lint_opts.push((lint.lint, *level));
-              }
+    let mut lint_opts = vec!();
+    let mut describe_lints = false;
+
+    for &level in [lint::Allow, lint::Warn, lint::Deny, lint::Forbid].iter() {
+        for lint_name in matches.opt_strs(level.as_str()).move_iter() {
+            if lint_name.as_slice() == "help" {
+                describe_lints = true;
+            } else {
+                lint_opts.push((lint_name.replace("-", "_").into_string(), level));
             }
         }
     }
@@ -752,6 +739,7 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
         optimize: opt_level,
         debuginfo: debuginfo,
         lint_opts: lint_opts,
+        describe_lints: describe_lints,
         output_types: output_types,
         addl_lib_search_paths: RefCell::new(addl_lib_search_paths),
         maybe_sysroot: sysroot_opt,

src/librustc/driver/driver.rs

@@ -767,15 +767,15 @@ pub fn collect_crate_types(session: &Session,
                 }
                 Some(ref n) if n.equiv(&("bin")) => Some(config::CrateTypeExecutable),
                 Some(_) => {
-                    session.add_lint(lint::UnknownCrateType,
+                    session.add_lint(lint::builtin::unknown_crate_type,
                                      ast::CRATE_NODE_ID,
                                      a.span,
                                      "invalid `crate_type` \
                                       value".to_string());
                     None
                 }
                 _ => {
-                    session.add_lint(lint::UnknownCrateType,
+                    session.add_lint(lint::builtin::unknown_crate_type,
                                      ast::CRATE_NODE_ID,
                                      a.span,
                                      "`crate_type` requires a \

src/librustc/driver/mod.rs

@@ -17,7 +17,6 @@ use lint;
 use metadata;
 
 use std::any::AnyRefExt;
-use std::cmp;
 use std::io;
 use std::os;
 use std::str;
@@ -50,6 +49,12 @@ fn run_compiler(args: &[String]) {
         None => return
     };
 
+    let sopts = config::build_session_options(&matches);
+    if sopts.describe_lints {
+        describe_lints();
+        return;
+    }
+
     let (input, input_file_path) = match matches.free.len() {
         0u => early_error("no input filename given"),
         1u => {
@@ -66,7 +71,6 @@ fn run_compiler(args: &[String]) {
         _ => early_error("multiple input filenames provided")
     };
 
-    let sopts = config::build_session_options(&matches);
     let sess = build_session(sopts, input_file_path);
     let cfg = config::build_configuration(&sess);
     let odir = matches.opt_str("out-dir").map(|o| Path::new(o));
@@ -124,7 +128,7 @@ Additional help:
                              config::optgroups().as_slice()));
 }
 
-fn describe_warnings() {
+fn describe_lints() {
     println!("
 Available lint options:
     -W <foo>           Warn about <foo>
@@ -133,30 +137,32 @@ Available lint options:
     -F <foo>           Forbid <foo> (deny, and deny all overrides)
 ");
 
-    let lint_dict = lint::get_lint_dict();
-    let mut lint_dict = lint_dict.move_iter()
-                                 .map(|(k, v)| (v, k))
-                                 .collect::<Vec<(lint::LintSpec, &'static str)> >();
-    lint_dict.as_mut_slice().sort();
+    let mut builtin_specs = lint::builtin_lint_specs();
+    builtin_specs.sort_by(|x, y| {
+        match x.default_level.cmp(&y.default_level) {
+            Equal => x.name.cmp(&y.name),
+            r => r,
+        }
+    });
+
+    // FIXME: What if someone uses combining characters or East Asian fullwidth
+    // characters in a lint name?!?!?
+    let max_name_len = builtin_specs.iter()
+        .map(|&s| s.name.char_len())
+        .max().unwrap_or(0);
+    let padded = |x: &str| {
+        format!("{}{}", " ".repeat(max_name_len - x.char_len()), x)
+    };
 
-    let mut max_key = 0;
-    for &(_, name) in lint_dict.iter() {
-        max_key = cmp::max(name.len(), max_key);
-    }
-    fn padded(max: uint, s: &str) -> String {
-        format!("{}{}", " ".repeat(max - s.len()), s)
-    }
     println!("\nAvailable lint checks:\n");
-    println!("    {}  {:7.7s}  {}",
-             padded(max_key, "name"), "default", "meaning");
-    println!("    {}  {:7.7s}  {}\n",
-             padded(max_key, "----"), "-------", "-------");
-    for (spec, name) in lint_dict.move_iter() {
-        let name = name.replace("_", "-");
+    println!("    {}  {:7.7s}  {}", padded("name"), "default", "meaning");
+    println!("    {}  {:7.7s}  {}", padded("----"), "-------", "-------");
+    println!("");
+
+    for spec in builtin_specs.move_iter() {
+        let name = spec.name.replace("_", "-");
         println!("    {}  {:7.7s}  {}",
-                 padded(max_key, name.as_slice()),
-                 lint::level_to_str(spec.default),
-                 spec.desc);
+            padded(name.as_slice()), spec.default_level.as_str(), spec.desc);
     }
     println!("");
 }
@@ -214,12 +220,7 @@ pub fn handle_options(mut args: Vec<String>) -> Option<getopts::Matches> {
         return None;
     }
 
-    let lint_flags = matches.opt_strs("W").move_iter().collect::<Vec<_>>().append(
-                                    matches.opt_strs("warn").as_slice());
-    if lint_flags.iter().any(|x| x.as_slice() == "help") {
-        describe_warnings();
-        return None;
-    }
+    // Don't handle -W help here, because we might first load plugins.
 
     let r = matches.opt_strs("Z");
     if r.iter().any(|x| x.as_slice() == "help") {

src/librustc/driver/session.rs

@@ -106,16 +106,17 @@ impl Session {
         self.diagnostic().handler().unimpl(msg)
     }
     pub fn add_lint(&self,
-                    lint: lint::LintId,
+                    lint: &'static lint::Lint,
                     id: ast::NodeId,
                     sp: Span,
                     msg: String) {
+        let lint_id = lint::LintId::of(lint);
         let mut lints = self.lints.borrow_mut();
         match lints.find_mut(&id) {
-            Some(arr) => { arr.push((lint, sp, msg)); return; }
+            Some(arr) => { arr.push((lint_id, sp, msg)); return; }
             None => {}
         }
-        lints.insert(id, vec!((lint, sp, msg)));
+        lints.insert(id, vec!((lint_id, sp, msg)));
     }
     pub fn next_node_id(&self) -> ast::NodeId {
         self.reserve_node_ids(1)

src/librustc/front/feature_gate.rs

@@ -409,7 +409,7 @@ pub fn check_crate(sess: &Session, krate: &ast::Crate) {
                                                      directive not necessary");
                         }
                         None => {
-                            sess.add_lint(lint::UnknownFeatures,
+                            sess.add_lint(lint::builtin::unknown_features,
                                           ast::CRATE_NODE_ID,
                                           mi.span,
                                           "unknown feature".to_string());

src/librustc/lib.rs

@@ -127,6 +127,15 @@ pub mod lib {
     pub mod llvmdeps;
 }
 
+// A private module so that macro-expanded idents like
+// `::rustc::lint::Lint` will also work in `rustc` itself.
+//
+// `libstd` uses the same trick.
+#[doc(hidden)]
+mod rustc {
+    pub use lint;
+}
+
 pub fn main() {
     let args = std::os::args().iter()
                               .map(|x| x.to_string())