de-closured the item name getter

src/len_zero.rs

@@ -5,7 +5,7 @@ use syntax::codemap::{Span, Spanned};
 use rustc::middle::def_id::DefId;
 use rustc::middle::ty::{self, MethodTraitItemId, ImplOrTraitItemId};
 
-use utils::{snippet, span_lint, walk_ptrs_ty, with_item_name};
+use utils::{get_item_name, snippet, span_lint, walk_ptrs_ty};
 
 declare_lint!(pub LEN_ZERO, Warn,
               "checking `.len() == 0` or `.len() > 0` (or similar) when `.is_empty()` \
@@ -91,8 +91,8 @@ fn is_self_sig(sig: &MethodSig) -> bool {
 
 fn check_cmp(cx: &Context, span: Span, left: &Expr, right: &Expr, op: &str) {    
     // check if we are in an is_empty() method 
-    if let Some(true) = with_item_name(cx, left, |n| n == "is_empty") {
+    if let Some(name) = get_item_name(cx, left) {
-        return;
+        if name == "is_empty" { return; }
     }
     match (&left.node, &right.node) {
         (&ExprLit(ref lit), &ExprMethodCall(ref method, _, ref args)) =>

src/misc.rs

@@ -7,7 +7,7 @@ use syntax::codemap::{Span, Spanned};
 use rustc_front::visit::FnKind;
 use rustc::middle::ty;
 
-use utils::{match_path, snippet, span_lint, walk_ptrs_ty, with_item_name};
+use utils::{get_item_name, match_path, snippet, span_lint, walk_ptrs_ty};
 use consts::constant;
 
 declare_lint!(pub TOPLEVEL_REF_ARG, Warn,
@@ -92,12 +92,13 @@ impl LintPass for FloatCmp {
                         false, |c| c.0.as_float().map_or(false, |f| f == 0.0)) {
                     return;
                 }
-                if let Some(true) = with_item_name(cx, expr, |name|
+                if let Some(name) = get_item_name(cx, expr) {
-                        name == "eq" || name == "ne" ||
+                    if name == "eq" || name == "ne" ||
                             name.as_str().starts_with("eq_") ||
-                        name.as_str().ends_with("_eq")) {
+                            name.as_str().ends_with("_eq") {
                         return;
                     }
+                }
                 span_lint(cx, FLOAT_CMP, expr.span, &format!(
                     "{}-comparison of f32 or f64 detected. Consider changing this to \
                      `abs({} - {}) < epsilon` for some suitable value of epsilon",

src/utils.rs

@@ -100,14 +100,14 @@ pub fn match_path(path: &Path, segments: &[&str]) -> bool {
         |(a, b)| &a.identifier.name == b)
 }
 
-pub fn with_item_name<T, F>(cx: &Context, expr: &Expr, f: F) -> Option<T>
+/// get the name of the item the expression is in, if available
-where F: FnOnce(Name) -> T {
+pub fn get_item_name(cx: &Context, expr: &Expr) -> Option<Name> {
     let parent_id = cx.tcx.map.get_parent(expr.id);
     match cx.tcx.map.find(parent_id) {
         Some(NodeItem(&Item{ ref ident, .. })) |
         Some(NodeTraitItem(&TraitItem{ id: _, ref ident, .. })) |
         Some(NodeImplItem(&ImplItem{ id: _, ref ident, .. })) => {
-            Some(f(ident.name))
+            Some(ident.name)
         },
         _ => None,
     }