Unify error messages for iterables and lists.

sdk/lib/collection/iterable.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart.collection;
 
 /**
  * This [Iterable] mixin implements all [Iterable] members except `iterator`.
  *
  * All other methods are implemented in terms of `iterator`.
@@ skipping 13 matching lines @@
     return false;
   }
 
   void forEach(void f(E element)) {
     for (E element in this) f(element);
   }
 
   E reduce(E combine(E value, E element)) {
     Iterator<E> iterator = this.iterator;
     if (!iterator.moveNext()) {
-      throw new StateError("No elements");
+      throw IterableElementError.noElement();
     }
     E value = iterator.current;
     while (iterator.moveNext()) {
       value = combine(value, iterator.current);
     }
     return value;
   }
 
   dynamic fold(var initialValue,
                dynamic combine(var previousValue, E element)) {
@@ skipping 65 matching lines @@
     return new SkipIterable<E>(this, n);
   }
 
   Iterable<E> skipWhile(bool test(E value)) {
     return new SkipWhileIterable<E>(this, test);
   }
 
   E get first {
     Iterator it = iterator;
     if (!it.moveNext()) {
-      throw new StateError("No elements");
+      throw IterableElementError.noElement();
     }
     return it.current;
   }
 
   E get last {
     Iterator it = iterator;
     if (!it.moveNext()) {
-      throw new StateError("No elements");
+      throw IterableElementError.noElement();
     }
     E result;
     do {
       result = it.current;
     } while(it.moveNext());
     return result;
   }
 
   E get single {
     Iterator it = iterator;
-    if (!it.moveNext()) throw new StateError("No elements");
+    if (!it.moveNext()) throw IterableElementError.noElement();
     E result = it.current;
-    if (it.moveNext()) throw new StateError("More than one element");
+    if (it.moveNext()) throw IterableElementError.tooMany();
     return result;
   }
 
   dynamic firstWhere(bool test(E value), { Object orElse() }) {
     for (E element in this) {
       if (test(element)) return element;
     }
     if (orElse != null) return orElse();
-    throw new StateError("No matching element");
+    throw IterableElementError.noElement();
   }
 
   dynamic lastWhere(bool test(E value), { Object orElse() }) {
     E result = null;
     bool foundMatching = false;
     for (E element in this) {
       if (test(element)) {
         result = element;
         foundMatching = true;
       }
     }
     if (foundMatching) return result;
     if (orElse != null) return orElse();
-    throw new StateError("No matching element");
+    throw IterableElementError.noElement();
   }
 
   E singleWhere(bool test(E value)) {
     E result = null;
     bool foundMatching = false;
     for (E element in this) {
       if (test(element)) {
         if (foundMatching) {
-          throw new StateError("More than one matching element");
+          throw IterableElementError.tooMany();
         }
         result = element;
         foundMatching = true;
       }
     }
     if (foundMatching) return result;
-    throw new StateError("No matching element");
+    throw IterableElementError.noElement();
   }
 
   E elementAt(int index) {
     if (index is! int || index < 0) throw new RangeError.value(index);
     int remaining = index;
     for (E element in this) {
       if (remaining == 0) return element;
       remaining--;
     }
     throw new RangeError.value(index);
@@ skipping 27 matching lines @@
     return false;
   }
 
   void forEach(void f(E element)) {
     for (E element in this) f(element);
   }
 
   E reduce(E combine(E value, E element)) {
     Iterator<E> iterator = this.iterator;
     if (!iterator.moveNext()) {
-      throw new StateError("No elements");
+      throw IterableElementError.noElement();
     }
     E value = iterator.current;
     while (iterator.moveNext()) {
       value = combine(value, iterator.current);
     }
     return value;
   }
 
   dynamic fold(var initialValue,
                dynamic combine(var previousValue, E element)) {
@@ skipping 65 matching lines @@
     return new SkipIterable<E>(this, n);
   }
 
   Iterable<E> skipWhile(bool test(E value)) {
     return new SkipWhileIterable<E>(this, test);
   }
 
   E get first {
     Iterator it = iterator;
     if (!it.moveNext()) {
-      throw new StateError("No elements");
+      throw IterableElementError.noElement();
     }
     return it.current;
   }
 
   E get last {
     Iterator it = iterator;
     if (!it.moveNext()) {
-      throw new StateError("No elements");
+      throw IterableElementError.noElement();
     }
     E result;
     do {
       result = it.current;
     } while(it.moveNext());
     return result;
   }
 
   E get single {
     Iterator it = iterator;
-    if (!it.moveNext()) throw new StateError("No elements");
+    if (!it.moveNext()) throw IterableElementError.noElement();
     E result = it.current;
-    if (it.moveNext()) throw new StateError("More than one element");
+    if (it.moveNext()) throw IterableElementError.tooMany();
     return result;
   }
 
   dynamic firstWhere(bool test(E value), { Object orElse() }) {
     for (E element in this) {
       if (test(element)) return element;
     }
     if (orElse != null) return orElse();
-    throw new StateError("No matching element");
+    throw IterableElementError.noElement();
   }
 
   dynamic lastWhere(bool test(E value), { Object orElse() }) {
     E result = null;
     bool foundMatching = false;
     for (E element in this) {
       if (test(element)) {
         result = element;
         foundMatching = true;
       }
     }
     if (foundMatching) return result;
     if (orElse != null) return orElse();
-    throw new StateError("No matching element");
+    throw IterableElementError.noElement();
   }
 
   E singleWhere(bool test(E value)) {
     E result = null;
     bool foundMatching = false;
     for (E element in this) {
       if (test(element)) {
         if (foundMatching) {
-          throw new StateError("More than one matching element");
+          throw IterableElementError.tooMany();
         }
         result = element;
         foundMatching = true;
       }
     }
     if (foundMatching) return result;
-    throw new StateError("No matching element");
+    throw IterableElementError.noElement();
   }
 
   E elementAt(int index) {
     if (index is! int || index < 0) throw new RangeError.value(index);
     int remaining = index;
     for (E element in this) {
       if (remaining == 0) return element;
       remaining--;
     }
     throw new RangeError.value(index);
@@ skipping 131 matching lines @@
       elision = "...";
       length += ELLIPSIS_SIZE + OVERHEAD;
     }
   }
   if (elision != null) {
     parts.add(elision);
   }
   parts.add(penultimateString);
   parts.add(ultimateString);
 }