rustc: Fix for-range loops that can use iterators

Transform range loops that can be regular iterator loops.

src/compiletest/runtest.rs

@@ -413,8 +413,8 @@ fn check_expected_errors(expected_errors: ~[errors::ExpectedError],
         }
     }
 
-    for i in range(0u, found_flags.len()) {
+    for (i, &flag) in found_flags.iter().enumerate() {
-        if !found_flags[i] {
+        if !flag {
             let ee = &expected_errors[i];
             fatal_ProcRes(fmt!("expected %s on line %u not found: %s",
                                ee.kind, ee.line, ee.msg), ProcRes);

src/librustc/middle/borrowck/check_loans.rs

@@ -159,10 +159,10 @@ impl<'self> CheckLoanCtxt<'self> {
             true
         };
 
-        for i in range(0u, new_loan_indices.len()) {
+        for (i, &x) in new_loan_indices.iter().enumerate() {
-            let old_loan = &self.all_loans[new_loan_indices[i]];
+            let old_loan = &self.all_loans[x];
-            for j in range(i+1, new_loan_indices.len()) {
+            for &y in new_loan_indices.slice_from(i+1).iter() {
-                let new_loan = &self.all_loans[new_loan_indices[j]];
+                let new_loan = &self.all_loans[y];
                 self.report_error_if_loans_conflict(old_loan, new_loan);
             }
         }

src/librustc/middle/dataflow.rs

@@ -983,10 +983,10 @@ fn bitwise(out_vec: &mut [uint],
            op: &fn(uint, uint) -> uint) -> bool {
     assert_eq!(out_vec.len(), in_vec.len());
     let mut changed = false;
-    for i in range(0u, out_vec.len()) {
+    for (out_elt, in_elt) in out_vec.mut_iter().zip(in_vec.iter()) {
-        let old_val = out_vec[i];
+        let old_val = *out_elt;
-        let new_val = op(old_val, in_vec[i]);
+        let new_val = op(old_val, *in_elt);
-        out_vec[i] = new_val;
+        *out_elt = new_val;
         changed |= (old_val != new_val);
     }
     changed

src/librustc/middle/trans/base.rs

@@ -1742,8 +1742,7 @@ pub fn copy_args_to_allocas(fcx: @mut FunctionContext,
         _ => {}
     }
 
-    for arg_n in range(0u, arg_tys.len()) {
+    for (arg_n, &arg_ty) in arg_tys.iter().enumerate() {
-        let arg_ty = arg_tys[arg_n];
         let raw_llarg = raw_llargs[arg_n];
 
         // For certain mode/type combinations, the raw llarg values are passed

src/librustc/middle/trans/cabi_x86_64.rs

@@ -145,8 +145,8 @@ fn classify_ty(ty: Type) -> ~[RegClass] {
     }
 
     fn all_mem(cls: &mut [RegClass]) {
-        for i in range(0u, cls.len()) {
+        for elt in cls.mut_iter() {
-            cls[i] = Memory;
+            *elt = Memory;
         }
     }
 

src/librustc/middle/trans/type_use.rs

@@ -205,15 +205,8 @@ pub fn type_uses_for(ccx: @mut CrateContext, fn_id: def_id, n_tps: uint)
 
 pub fn type_needs(cx: &Context, use_: uint, ty: ty::t) {
     // Optimization -- don't descend type if all params already have this use
-    let len = {
+    if cx.uses.iter().any(|&elt| elt & use_ != use_) {
-        let uses = &*cx.uses;
-        uses.len()
-    };
-    for i in range(0u, len) {
-        if cx.uses[i] & use_ != use_ {
         type_needs_inner(cx, use_, ty, @Nil);
-            return;
-        }
     }
 }
 

src/librustc/middle/typeck/check/method.rs

@@ -772,8 +772,8 @@ impl<'self> LookupContext<'self> {
             self.tcx().sess.span_err(
                 self.expr.span,
                 "multiple applicable methods in scope");
-            for idx in range(0u, relevant_candidates.len()) {
+            for (idx, candidate) in relevant_candidates.iter().enumerate() {
-                self.report_candidate(idx, &relevant_candidates[idx].origin);
+                self.report_candidate(idx, &candidate.origin);
             }
         }
 

src/librustc/middle/typeck/coherence.rs

@@ -554,8 +554,8 @@ impl CoherenceChecker {
 
         let mut provided_names = HashSet::new();
         // Implemented methods
-        for i in range(0u, all_methods.len()) {
+        for elt in all_methods.iter() {
-            provided_names.insert(all_methods[i].ident);
+            provided_names.insert(elt.ident);
         }
 
         let r = ty::trait_methods(tcx, trait_did);

src/librustc/middle/typeck/infer/region_inference/mod.rs

@@ -374,8 +374,8 @@ impl RegionVarBindings {
     pub fn vars_created_since_snapshot(&mut self, snapshot: uint)
                                        -> ~[RegionVid] {
         do vec::build |push| {
-            for i in range(snapshot, self.undo_log.len()) {
+            for &elt in self.undo_log.slice_from(snapshot).iter() {
-                match self.undo_log[i] {
+                match elt {
                     AddVar(vid) => push(vid),
                     _ => ()
                 }