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Rollup merge of #49734 - alexcrichton:generalize-token-stream, r=nikomatsakis

proc_macro: Generalize `FromIterator` impl

While never intended to be stable we forgot that trait impls are insta-stable!
This construction of `FromIterator` wasn't our first choice of how to stabilize
the impl but our hands are tied at this point, so revert back to the original
definition of `FromIterator` before #49597

Closes #49725
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kennytm 2018-04-12 03:37:12 +08:00
commit 574c0502f1
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@ -140,9 +140,16 @@ impl From<TokenTree> for TokenStream {
#[unstable(feature = "proc_macro", issue = "38356")]
impl iter::FromIterator<TokenTree> for TokenStream {
fn from_iter<I: IntoIterator<Item = TokenTree>>(trees: I) -> Self {
trees.into_iter().map(TokenStream::from).collect()
}
}
#[unstable(feature = "proc_macro", issue = "38356")]
impl iter::FromIterator<TokenStream> for TokenStream {
fn from_iter<I: IntoIterator<Item = TokenStream>>(streams: I) -> Self {
let mut builder = tokenstream::TokenStreamBuilder::new();
for tree in trees {
builder.push(tree.to_internal());
for stream in streams {
builder.push(stream.0);
}
TokenStream(builder.build())
}