@@ -19,39 +19,53 @@ use std::str;
1919/// Collected spans during parsing for places where a certain feature was
2020/// used and should be feature gated accordingly in `check_crate`.
2121#[ derive( Default ) ]
22- crate struct GatedSpans {
23- /// Spans collected for gating `let_chains`, e.g. `if a && let b = c {}`.
24- crate let_chains : Lock < Vec < Span > > ,
25- /// Spans collected for gating `async_closure`, e.g. `async || ..`.
26- crate async_closure : Lock < Vec < Span > > ,
27- /// Spans collected for gating `yield e?` expressions (`generators` gate).
28- crate yields : Lock < Vec < Span > > ,
29- /// Spans collected for gating `or_patterns`, e.g. `Some(Foo | Bar)`.
30- crate or_patterns : Lock < Vec < Span > > ,
31- /// Spans collected for gating `const_extern_fn`, e.g. `const extern fn foo`.
32- crate const_extern_fn : Lock < Vec < Span > > ,
33- /// Spans collected for gating `trait_alias`, e.g. `trait Foo = Ord + Eq;`.
34- pub trait_alias : Lock < Vec < Span > > ,
35- /// Spans collected for gating `associated_type_bounds`, e.g. `Iterator<Item: Ord>`.
36- pub associated_type_bounds : Lock < Vec < Span > > ,
37- /// Spans collected for gating `crate_visibility_modifier`, e.g. `crate fn`.
38- pub crate_visibility_modifier : Lock < Vec < Span > > ,
39- /// Spans collected for gating `const_generics`, e.g. `const N: usize`.
40- pub const_generics : Lock < Vec < Span > > ,
41- /// Spans collected for gating `decl_macro`, e.g. `macro m() {}`.
42- pub decl_macro : Lock < Vec < Span > > ,
43- /// Spans collected for gating `box_patterns`, e.g. `box 0`.
44- pub box_patterns : Lock < Vec < Span > > ,
45- /// Spans collected for gating `exclusive_range_pattern`, e.g. `0..2`.
46- pub exclusive_range_pattern : Lock < Vec < Span > > ,
47- /// Spans collected for gating `try_blocks`, e.g. `try { a? + b? }`.
48- pub try_blocks : Lock < Vec < Span > > ,
49- /// Spans collected for gating `label_break_value`, e.g. `'label: { ... }`.
50- pub label_break_value : Lock < Vec < Span > > ,
51- /// Spans collected for gating `box_syntax`, e.g. `box $expr`.
52- pub box_syntax : Lock < Vec < Span > > ,
53- /// Spans collected for gating `type_ascription`, e.g. `42: usize`.
54- pub type_ascription : Lock < Vec < Span > > ,
22+ pub struct GatedSpans {
23+ pub spans : Lock < FxHashMap < Symbol , Vec < Span > > > ,
24+ }
25+
26+ impl GatedSpans {
27+ /// Feature gate the given `span` under the given `feature`
28+ /// which is same `Symbol` used in `active.rs`.
29+ pub fn gate ( & self , feature : Symbol , span : Span ) {
30+ self . spans
31+ . borrow_mut ( )
32+ . entry ( feature)
33+ . or_default ( )
34+ . push ( span) ;
35+ }
36+
37+ /// Ungate the last span under the given `feature`.
38+ /// Panics if the given `span` wasn't the last one.
39+ ///
40+ /// Using this is discouraged unless you have a really good reason to.
41+ pub fn ungate_last ( & self , feature : Symbol , span : Span ) {
42+ let removed_span = self . spans
43+ . borrow_mut ( )
44+ . entry ( feature)
45+ . or_default ( )
46+ . pop ( )
47+ . unwrap ( ) ;
48+ debug_assert_eq ! ( span, removed_span) ;
49+ }
50+
51+ /// Is the provided `feature` gate ungated currently?
52+ ///
53+ /// Using this is discouraged unless you have a really good reason to.
54+ pub fn is_ungated ( & self , feature : Symbol ) -> bool {
55+ self . spans
56+ . borrow ( )
57+ . get ( & feature)
58+ . map_or ( true , |spans| spans. is_empty ( ) )
59+ }
60+
61+ /// Prepend the given set of `spans` onto the set in `self`.
62+ pub fn merge ( & self , mut spans : FxHashMap < Symbol , Vec < Span > > ) {
63+ let mut inner = self . spans . borrow_mut ( ) ;
64+ for ( gate, mut gate_spans) in inner. drain ( ) {
65+ spans. entry ( gate) . or_default ( ) . append ( & mut gate_spans) ;
66+ }
67+ * inner = spans;
68+ }
5569}
5670
5771/// Info about a parsing session.
@@ -72,7 +86,7 @@ pub struct ParseSess {
7286/// analysis.
7387pub ambiguous_block_expr_parse : Lock < FxHashMap < Span , Span > > ,
7488 pub injected_crate_name : Once < Symbol > ,
75- crate gated_spans : GatedSpans ,
89+ pub gated_spans : GatedSpans ,
7690 /// The parser has reached `Eof` due to an unclosed brace. Used to silence unnecessary errors.
7791pub reached_eof : Lock < bool > ,
7892}
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