rustc: Add a --cap-lints flag to the compiler

src/librustc/lint/context.rs

@@ -34,6 +34,7 @@ use lint::builtin;
 use util::nodemap::FnvHashMap;
 
 use std::cell::RefCell;
+use std::cmp;
 use std::mem;
 use syntax::ast_util::IdVisitingOperation;
 use syntax::attr::AttrMetaMethods;
@@ -66,6 +67,9 @@ pub struct LintStore {
     /// Map of registered lint groups to what lints they expand to. The bool
     /// is true if the lint group was added by a plugin.
     lint_groups: FnvHashMap<&'static str, (Vec<LintId>, bool)>,
+
+    /// Maximum level a lint can be
+    lint_cap: Option<Level>,
 }
 
 /// The targed of the `by_name` map, which accounts for renaming/deprecation.
@@ -94,7 +98,10 @@ impl LintStore {
         }
     }
 
-    fn set_level(&mut self, lint: LintId, lvlsrc: LevelSource) {
+    fn set_level(&mut self, lint: LintId, mut lvlsrc: LevelSource) {
+        if let Some(cap) = self.lint_cap {
+            lvlsrc.0 = cmp::min(lvlsrc.0, cap);
+        }
         if lvlsrc.0 == Allow {
             self.levels.remove(&lint);
         } else {
@@ -109,6 +116,7 @@ impl LintStore {
             by_name: FnvHashMap(),
             levels: FnvHashMap(),
             lint_groups: FnvHashMap(),
+            lint_cap: None,
         }
     }
 
@@ -227,6 +235,13 @@ impl LintStore {
                 }
             }
         }
+
+        self.lint_cap = sess.opts.lint_cap;
+        if let Some(cap) = self.lint_cap {
+            for level in self.levels.iter_mut().map(|p| &mut (p.1).0) {
+                *level = cmp::min(*level, cap);
+            }
+        }
     }
 }
 

src/librustc/session/config.rs

@@ -84,6 +84,7 @@ pub struct Options {
     pub debug_assertions: bool,
     pub debuginfo: DebugInfoLevel,
     pub lint_opts: Vec<(String, lint::Level)>,
+    pub lint_cap: Option<lint::Level>,
     pub describe_lints: bool,
     pub output_types: Vec<OutputType>,
     // This was mutable for rustpkg, which updates search paths based on the
@@ -203,6 +204,7 @@ pub fn basic_options() -> Options {
         optimize: No,
         debuginfo: NoDebugInfo,
         lint_opts: Vec::new(),
+        lint_cap: None,
         describe_lints: false,
         output_types: Vec::new(),
         search_paths: SearchPaths::new(),
@@ -792,6 +794,9 @@ pub fn rustc_short_optgroups() -> Vec<RustcOptGroup> {
         opt::multi("A", "allow", "Set lint allowed", "OPT"),
         opt::multi("D", "deny", "Set lint denied", "OPT"),
         opt::multi("F", "forbid", "Set lint forbidden", "OPT"),
+        opt::multi("", "cap-lints", "Set the most restrictive lint level. \
+                                     More restrictive lints are capped at this \
+                                     level", "LEVEL"),
         opt::multi("C", "codegen", "Set a codegen option", "OPT[=VALUE]"),
         opt::flag("V", "version", "Print version info and exit"),
         opt::flag("v", "verbose", "Use verbose output"),
@@ -860,6 +865,12 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
         }
     }
 
+    let lint_cap = matches.opt_str("cap-lints").map(|cap| {
+        lint::Level::from_str(&cap).unwrap_or_else(|| {
+            early_error(&format!("unknown lint level: `{}`", cap))
+        })
+    });
+
     let debugging_opts = build_debugging_options(matches);
 
     let parse_only = debugging_opts.parse_only;
@@ -1023,6 +1034,7 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
         optimize: opt_level,
         debuginfo: debuginfo,
         lint_opts: lint_opts,
+        lint_cap: lint_cap,
         describe_lints: describe_lints,
         output_types: output_types,
         search_paths: search_paths,

src/test/compile-fail/bad-lint-cap.rs

@@ -0,0 +1,14 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// compile-flags: --cap-lints test
+// error-pattern: unknown lint level: `test`
+
+fn main() {}

src/test/compile-fail/bad-lint-cap2.rs

@@ -0,0 +1,17 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// compile-flags: --cap-lints deny
+
+#![deny(warnings)]
+
+use std::option; //~ ERROR
+
+fn main() {}

src/test/compile-fail/bad-lint-cap3.rs

@@ -0,0 +1,20 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// compile-flags: --cap-lints warn
+
+#![deny(warnings)]
+#![feature(rustc_attrs)]
+
+use std::option; //~ WARN
+
+#[rustc_error]
+fn main() {} //~ ERROR: compilation successful
+

src/test/run-pass/lint-cap.rs

@@ -0,0 +1,18 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// compile-flags: --cap-lints allow
+
+#![deny(warnings)]
+
+use std::option;
+
+fn main() {}
+