add an internal lint that catches misordered paths

Author: oli-obk

clippy_lints/src/lib.rs

@@ -169,6 +169,7 @@ pub fn register_plugins(reg: &mut rustc_plugin::Registry) {
     // end deprecated lints, do not remove this comment, it’s used in `update_lints`
 
     reg.register_late_lint_pass(box serde::Serde);
+    reg.register_early_lint_pass(box utils::internal_lints::Clippy);
     reg.register_late_lint_pass(box types::TypePass);
     reg.register_late_lint_pass(box booleans::NonminimalBool);
     reg.register_late_lint_pass(box misc::TopLevelRefPass);

clippy_lints/src/utils/internal_lints.rs

@@ -0,0 +1,53 @@
+use rustc::lint::*;
+use utils::span_lint;
+use syntax::parse::token::InternedString;
+use syntax::ast::*;
+
+/// **What it does:** This lint checks for various things we like to keep tidy in clippy
+///
+/// **Why is this bad?** ???
+///
+/// **Known problems:** None.
+///
+/// **Example:** wrong ordering of the util::paths constants
+declare_lint! {
+    pub CLIPPY_LINTS_INTERNAL, Allow,
+    "Various things that will negatively affect your clippy experience"
+}
+
+
+#[derive(Copy, Clone)]
+pub struct Clippy;
+
+impl LintPass for Clippy {
+    fn get_lints(&self) -> LintArray {
+        lint_array!(CLIPPY_LINTS_INTERNAL)
+    }
+}
+
+impl EarlyLintPass for Clippy {
+    fn check_crate(&mut self, cx: &EarlyContext, krate: &Crate) {
+        if let Some(utils) = krate.module.items.iter().find(|item| item.ident.name.as_str() == "utils") {
+            if let ItemKind::Mod(ref utils_mod) = utils.node {
+                if let Some(paths) = utils_mod.items.iter().find(|item| item.ident.name.as_str() == "paths") {
+                    if let ItemKind::Mod(ref paths_mod) = paths.node {
+                        let mut last_name: Option<InternedString> = None;
+                        for item in &paths_mod.items {
+                            let name = item.ident.name.as_str();
+                            if let Some(ref last_name) = last_name {
+                                if **last_name > *name {
+                                    span_lint(cx,
+                                              CLIPPY_LINTS_INTERNAL,
+                                              item.span,
+                                              "this constant should be before the previous constant due to lexical ordering",
+                                    );
+                                }
+                            }
+                            last_name = Some(name);
+                        }
+                    }
+                }
+            }
+        }
+    }
+}

clippy_lints/src/utils/mod.rs

@@ -25,6 +25,7 @@ pub mod conf;
 mod hir;
 pub mod paths;
 pub mod sugg;
+pub mod internal_lints;
 pub use self::hir::{SpanlessEq, SpanlessHash};
 
 pub type MethodArgs = HirVec<P<Expr>>;

tests/dogfood.rs

@@ -17,7 +17,7 @@ fn dogfood() {
     let mut s = String::new();
     s.push_str(" -L target/debug/");
     s.push_str(" -L target/debug/deps");
-    s.push_str(" -Zextra-plugins=clippy -Ltarget_recur/debug -Dclippy_pedantic -Dclippy");
+    s.push_str(" -Zextra-plugins=clippy -Ltarget_recur/debug -Dclippy_pedantic -Dclippy -Dclippy_lints_internal");
     config.target_rustcflags = Some(s);
     if let Ok(name) = var("TESTNAME") {
         config.filter = Some(name.to_owned())
@@ -29,6 +29,7 @@ fn dogfood() {
     }
 
     config.mode = cfg_mode;
+    config.verbose = true;
 
     let files = ["src/main.rs", "src/lib.rs", "clippy_lints/src/lib.rs"];
 

util/update_lints.py

@@ -150,11 +150,10 @@ def main(print_only=False, check=False):
         return
 
     # collect all lints from source files
-    for root, _, files in os.walk('clippy_lints/src'):
-        for fn in files:
-            if fn.endswith('.rs'):
-                collect(lints, deprecated_lints, restriction_lints,
-                        os.path.join(root, fn))
+    for fn in os.listdir('clippy_lints/src'):
+        if fn.endswith('.rs'):
+            collect(lints, deprecated_lints, restriction_lints,
+                    os.path.join('clippy_lints', 'src', fn))
 
     # determine version
     with open('Cargo.toml') as fp: