Update range errors to agree on the numbers.

runtime/lib/array.cc

 // 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.
 
 #include "platform/assert.h"
 #include "vm/bootstrap_natives.h"
 #include "vm/assembler.h"
 #include "vm/exceptions.h"
 #include "vm/native_entry.h"
 #include "vm/object.h"
 
 namespace dart {
 
 DEFINE_NATIVE_ENTRY(List_allocate, 2) {
   // Implemented in FlowGraphBuilder::VisitNativeBody.
   UNREACHABLE();
   return Object::null();
 }
 
 
 DEFINE_NATIVE_ENTRY(List_getIndexed, 2) {
   const Array& array = Array::CheckedHandle(arguments->NativeArgAt(0));
   GET_NON_NULL_NATIVE_ARGUMENT(Smi, index, arguments->NativeArgAt(1));
   if ((index.Value() < 0) || (index.Value() >= array.Length())) {
-    Exceptions::ThrowRangeError("index", index, 0, array.Length());
+    Exceptions::ThrowRangeError("index", index, 0, array.Length() - 1);
   }
   return array.At(index.Value());
 }
 
 
 DEFINE_NATIVE_ENTRY(List_setIndexed, 3) {
   const Array& array = Array::CheckedHandle(arguments->NativeArgAt(0));
   GET_NON_NULL_NATIVE_ARGUMENT(Smi, index, arguments->NativeArgAt(1));
   const Instance& value = Instance::CheckedHandle(arguments->NativeArgAt(2));
   if ((index.Value() < 0) || (index.Value() >= array.Length())) {
-    Exceptions::ThrowRangeError("index", index, 0, array.Length());
+    Exceptions::ThrowRangeError("index", index, 0, array.Length() - 1);
   }
   array.SetAt(index.Value(), value);
   return Object::null();
 }
 
 
 DEFINE_NATIVE_ENTRY(List_getLength, 1) {
   const Array& array = Array::CheckedHandle(arguments->NativeArgAt(0));
   return Smi::New(array.Length());
 }
 
 
 // ObjectArray src, int start, int count, bool needTypeArgument.
 DEFINE_NATIVE_ENTRY(List_slice, 4) {
   const Array& src = Array::CheckedHandle(arguments->NativeArgAt(0));
   GET_NON_NULL_NATIVE_ARGUMENT(Smi, start, arguments->NativeArgAt(1));
   GET_NON_NULL_NATIVE_ARGUMENT(Smi, count, arguments->NativeArgAt(2));
   GET_NON_NULL_NATIVE_ARGUMENT(Bool, needs_type_arg, arguments->NativeArgAt(3));
+  intptr_t istart = start.Value();
+  if ((istart < 0) || (istart > src.Length())) {
+    Exceptions::ThrowRangeError(
+        "start",
+        Smi::Handle(Smi::New(istart)),

[Ivan Posva, 2015/09/11 09:12:50]

start

+        0,
+        src.Length());
+  }
   intptr_t icount = count.Value();
   // Zero count should be handled outside already.
   if ((icount <= 0) || (icount > src.Length())) {
     Exceptions::ThrowRangeError(
         "count",
         Smi::Handle(Smi::New(icount)),

[Ivan Posva, 2015/09/11 09:12:50]

count

-        1,
-        src.Length() + 1);
-  }
-  intptr_t istart = start.Value();
-  if ((istart < 0) || ((istart + icount) > src.Length())) {
-    Exceptions::ThrowRangeError(
-        "start",
-        Smi::Handle(Smi::New(istart)),
-        0,
-        src.Length() - icount + 1);
+        0,                        // This is the limit the user sees.
+        src.Length() - istart);

[srdjan, 2015/09/25 20:32:17]

Shouldn't this be "src.Length()" only.

[Lasse Reichstein Nielsen, 2015/09/25 23:28:22]

Probably. Maybe it would be simpler to pass `end` instead of `count` if that is
what the user is providing.

[Lasse Reichstein Nielsen, 2015/09/25 23:29:15]

... but that would mean changing "count" above to "end".
With the name "count", then this is the limit.

   }
 
   return src.Slice(istart, icount, needs_type_arg.value());
 }
 
 
 // Private factory, expects correct arguments.
 DEFINE_NATIVE_ENTRY(ImmutableList_from, 4) {
   // Ignore first argument of a thsi factory (type argument).
   const Array& from_array = Array::CheckedHandle(arguments->NativeArgAt(1));
   const Smi& smi_offset = Smi::CheckedHandle(arguments->NativeArgAt(2));
   const Smi& smi_length = Smi::CheckedHandle(arguments->NativeArgAt(3));
   const intptr_t length = smi_length.Value();
   const intptr_t offset = smi_offset.Value();
   const Array& result = Array::Handle(Array::New(length));
   Object& temp = Object::Handle();
   for (intptr_t i = 0; i < length; i++) {
     temp = from_array.At(i + offset);
     result.SetAt(i, temp);
   }
   result.MakeImmutable();
   return result.raw();
 }
 
 }  // namespace dart