Some fixes from dogfooding clippy

src/eq_op.rs

@@ -1,3 +1,4 @@
+#![allow(redundant_closure)] // FIXME (#116)
 use rustc::lint::*;
 use syntax::ast::*;
 use syntax::ast_util as ast_util;

src/lib.rs

@@ -1,6 +1,6 @@
 #![feature(plugin_registrar, box_syntax)]
 #![feature(rustc_private, collections)]
-#![allow(unused_imports)]
+#![allow(unused_imports, unknown_lints)]
 
 #[macro_use]
 extern crate syntax;

src/lifetimes.rs

@@ -103,7 +103,7 @@ fn could_use_elision(kind: FnKind, func: &FnDecl) -> bool {
 }
 
 /// Number of unique lifetimes in the given vector.
-fn unique_lifetimes(lts: &Vec<RefLt>) -> usize {
+fn unique_lifetimes(lts: &[RefLt]) -> usize {
     lts.iter().collect::<HashSet<_>>().len()
 }
 

src/loops.rs

@@ -31,7 +31,7 @@ impl LintPass for LoopsPass {
                     walk_expr(&mut visitor, body);
                     // linting condition: we only indexed one variable
                     if visitor.indexed.len() == 1 {
-                        let indexed = visitor.indexed.into_iter().next().unwrap();
+                        let indexed = visitor.indexed.into_iter().next().expect("Len was nonzero, but no contents found");
                         if visitor.nonindex {
                             span_lint(cx, NEEDLESS_RANGE_LOOP, expr.span, &format!(
                                 "the loop variable `{}` is used to index `{}`. Consider using \
@@ -72,7 +72,7 @@ impl LintPass for LoopsPass {
 
 /// Recover the essential nodes of a desugared for loop:
 /// `for pat in arg { body }` becomes `(pat, arg, body)`.
-fn recover_for_loop<'a>(expr: &'a Expr) -> Option<(&'a Pat, &'a Expr, &'a Expr)> {
+fn recover_for_loop<'a>(expr: &Expr) -> Option<(&Pat, &Expr, &Expr)> {
     if_let_chain! {
         [
             let ExprMatch(ref iterexpr, ref arms, _) = expr.node,

src/utils.rs

@@ -86,7 +86,7 @@ pub fn span_help_and_lint(cx: &Context, lint: &'static Lint, span: Span,
 }
 
 /// return the base type for references and raw pointers
-pub fn walk_ptrs_ty<'t>(ty: ty::Ty<'t>) -> ty::Ty<'t> {
+pub fn walk_ptrs_ty(ty: ty::Ty) -> ty::Ty {
     match ty.sty {
         ty::TyRef(_, ref tm) | ty::TyRawPtr(ref tm) => walk_ptrs_ty(tm.ty),
         _ => ty