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2 - Make more use of let_chains
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Continuation of #94376.

cc #53667
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c410-f3r committed Feb 26, 2022
1 parent 6f681a8 commit ef5601b
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Showing 5 changed files with 53 additions and 59 deletions.
11 changes: 5 additions & 6 deletions compiler/rustc_ast/src/attr/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -75,12 +75,11 @@ impl NestedMetaItem {
pub fn name_value_literal(&self) -> Option<(Symbol, &Lit)> {
self.meta_item().and_then(|meta_item| {
meta_item.meta_item_list().and_then(|meta_item_list| {
if meta_item_list.len() == 1 {
if let Some(ident) = meta_item.ident() {
if let Some(lit) = meta_item_list[0].literal() {
return Some((ident.name, lit));
}
}
if meta_item_list.len() == 1
&& let Some(ident) = meta_item.ident()
&& let Some(lit) = meta_item_list[0].literal()
{
return Some((ident.name, lit));
}
None
})
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5 changes: 3 additions & 2 deletions compiler/rustc_ast/src/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -12,11 +12,12 @@
#![feature(crate_visibility_modifier)]
#![feature(if_let_guard)]
#![feature(label_break_value)]
#![feature(nll)]
#![feature(let_chains)]
#![feature(min_specialization)]
#![recursion_limit = "256"]
#![feature(nll)]
#![feature(slice_internals)]
#![feature(stmt_expr_attributes)]
#![recursion_limit = "256"]

#[macro_use]
extern crate rustc_macros;
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20 changes: 8 additions & 12 deletions compiler/rustc_ast/src/token.rs
Original file line number Diff line number Diff line change
Expand Up @@ -504,10 +504,8 @@ impl Token {

/// Returns `true` if the token is an interpolated path.
fn is_path(&self) -> bool {
if let Interpolated(ref nt) = self.kind {
if let NtPath(..) = **nt {
return true;
}
if let Interpolated(ref nt) = self.kind && let NtPath(..) = **nt {
return true;
}
false
}
Expand All @@ -516,21 +514,19 @@ impl Token {
/// That is, is this a pre-parsed expression dropped into the token stream
/// (which happens while parsing the result of macro expansion)?
pub fn is_whole_expr(&self) -> bool {
if let Interpolated(ref nt) = self.kind {
if let NtExpr(_) | NtLiteral(_) | NtPath(_) | NtIdent(..) | NtBlock(_) = **nt {
return true;
}
if let Interpolated(ref nt) = self.kind
&& let NtExpr(_) | NtLiteral(_) | NtPath(_) | NtIdent(..) | NtBlock(_) = **nt
{
return true;
}

false
}

// Is the token an interpolated block (`$b:block`)?
pub fn is_whole_block(&self) -> bool {
if let Interpolated(ref nt) = self.kind {
if let NtBlock(..) = **nt {
return true;
}
if let Interpolated(ref nt) = self.kind && let NtBlock(..) = **nt {
return true;
}
false
}
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68 changes: 33 additions & 35 deletions compiler/rustc_ast/src/tokenstream.rs
Original file line number Diff line number Diff line change
Expand Up @@ -497,42 +497,40 @@ impl TokenStreamBuilder {

// If `self` is not empty and the last tree within the last stream is a
// token tree marked with `Joint`...
if let Some(TokenStream(ref mut last_stream_lrc)) = self.0.last_mut() {
if let Some((TokenTree::Token(last_token), Spacing::Joint)) = last_stream_lrc.last() {
// ...and `stream` is not empty and the first tree within it is
// a token tree...
let TokenStream(ref mut stream_lrc) = stream;
if let Some((TokenTree::Token(token), spacing)) = stream_lrc.first() {
// ...and the two tokens can be glued together...
if let Some(glued_tok) = last_token.glue(&token) {
// ...then do so, by overwriting the last token
// tree in `self` and removing the first token tree
// from `stream`. This requires using `make_mut()`
// on the last stream in `self` and on `stream`,
// and in practice this doesn't cause cloning 99.9%
// of the time.

// Overwrite the last token tree with the merged
// token.
let last_vec_mut = Lrc::make_mut(last_stream_lrc);
*last_vec_mut.last_mut().unwrap() = (TokenTree::Token(glued_tok), *spacing);

// Remove the first token tree from `stream`. (This
// is almost always the only tree in `stream`.)
let stream_vec_mut = Lrc::make_mut(stream_lrc);
stream_vec_mut.remove(0);

// Don't push `stream` if it's empty -- that could
// block subsequent token gluing, by getting
// between two token trees that should be glued
// together.
if !stream.is_empty() {
self.0.push(stream);
}
return;
}
}
if let Some(TokenStream(ref mut last_stream_lrc)) = self.0.last_mut()
&& let Some((TokenTree::Token(last_token), Spacing::Joint)) = last_stream_lrc.last()
// ...and `stream` is not empty and the first tree within it is
// a token tree...
&& let TokenStream(ref mut stream_lrc) = stream
&& let Some((TokenTree::Token(token), spacing)) = stream_lrc.first()
// ...and the two tokens can be glued together...
&& let Some(glued_tok) = last_token.glue(&token)
{
// ...then do so, by overwriting the last token
// tree in `self` and removing the first token tree
// from `stream`. This requires using `make_mut()`
// on the last stream in `self` and on `stream`,
// and in practice this doesn't cause cloning 99.9%
// of the time.

// Overwrite the last token tree with the merged
// token.
let last_vec_mut = Lrc::make_mut(last_stream_lrc);
*last_vec_mut.last_mut().unwrap() = (TokenTree::Token(glued_tok), *spacing);

// Remove the first token tree from `stream`. (This
// is almost always the only tree in `stream`.)
let stream_vec_mut = Lrc::make_mut(stream_lrc);
stream_vec_mut.remove(0);

// Don't push `stream` if it's empty -- that could
// block subsequent token gluing, by getting
// between two token trees that should be glued
// together.
if !stream.is_empty() {
self.0.push(stream);
}
return;
}
self.0.push(stream);
}
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8 changes: 4 additions & 4 deletions compiler/rustc_ast/src/util/literal.rs
Original file line number Diff line number Diff line change
Expand Up @@ -222,10 +222,10 @@ impl Lit {
}
token::Literal(lit) => lit,
token::Interpolated(ref nt) => {
if let token::NtExpr(expr) | token::NtLiteral(expr) = &**nt {
if let ast::ExprKind::Lit(lit) = &expr.kind {
return Ok(lit.clone());
}
if let token::NtExpr(expr) | token::NtLiteral(expr) = &**nt
&& let ast::ExprKind::Lit(lit) = &expr.kind
{
return Ok(lit.clone());
}
return Err(LitError::NotLiteral);
}
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