automated whitespace fixes
xfail run-pass/auto-encode.rs
auto merge of #7116 : thestinger/rust/whitespace, r=luqmana
Add caches for method and impl metadata

The lookups for these items in external crates currently cause repeated
decoding of the EBML metadata, which is pretty slow. Adding caches to
avoid the repeated decoding reduces the time required for the type
checking of librustc by about 25%.
add IteratorUtil to the prelude
rm ExtendedMutableIter

replaced with `xs.mut_iter().enumerate()`
rm MutableIter

replaced with mutable implementations of Iterator
rm CopyableNonstrictIter

copies can just be done explicitly: `xs.transform(|x|x.clone())`
auto merge of #7144 : dotdash/rust/caches, r=graydon

The lookups for these items in external crates currently cause repeated
decoding of the EBML metadata, which is pretty slow. Adding caches to
avoid the repeated decoding reduces the time required for the type
checking of librustc by about 25%.
auto merge of #7110 : thestinger/rust/iterator, r=brson
rustc: Don't continue to resolve if there's an error in lang_items

This confused me when it happened.