rust/src/libsyntax/feature_gate/mod.rs

65 lines
1.9 KiB
Rust
Raw Normal View History

//! # Feature gating
//!
2015-04-16 02:18:29 -05:00
//! This module implements the gating necessary for preventing certain compiler
//! features from being used by default. This module will crawl a pre-expanded
//! AST to ensure that there are no features which are used that are not
//! enabled.
//!
//! Features are enabled in programs via the crate-level attributes of
//! `#![feature(...)]` with a comma-separated list of features.
//!
//! For the purpose of future feature-tracking, once code for detection of feature
//! gate usage is added, *do not remove it again* even once the feature
//! becomes stable.
2015-02-03 16:31:06 -06:00
mod accepted;
mod removed;
mod active;
2019-08-22 11:32:31 -05:00
mod builtin_attrs;
2019-08-22 16:48:08 -05:00
mod check;
use std::fmt;
use crate::{edition::Edition, symbol::Symbol};
use syntax_pos::Span;
#[derive(Clone, Copy)]
pub enum State {
Accepted,
Active { set: fn(&mut Features, Span) },
Removed { reason: Option<&'static str> },
Stabilized { reason: Option<&'static str> },
}
impl fmt::Debug for State {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
State::Accepted { .. } => write!(f, "accepted"),
State::Active { .. } => write!(f, "active"),
State::Removed { .. } => write!(f, "removed"),
State::Stabilized { .. } => write!(f, "stabilized"),
}
}
}
#[derive(Debug, Clone)]
pub struct Feature {
state: State,
name: Symbol,
since: &'static str,
issue: Option<u32>,
edition: Option<Edition>,
description: &'static str,
}
2019-08-22 16:48:08 -05:00
pub use active::{Features, INCOMPLETE_FEATURES};
2019-08-22 11:32:31 -05:00
pub use builtin_attrs::{
AttributeGate, AttributeType, GatedCfg,
BuiltinAttribute, BUILTIN_ATTRIBUTES, BUILTIN_ATTRIBUTE_MAP,
deprecated_attributes, is_builtin_attr, is_builtin_attr_name,
};
2019-08-22 16:48:08 -05:00
pub use check::{
check_crate, check_attribute, get_features, feature_err, emit_feature_err,
2019-08-22 16:48:08 -05:00
Stability, GateIssue, UnstableFeatures,
EXPLAIN_STMT_ATTR_SYNTAX, EXPLAIN_UNSIZED_TUPLE_COERCION,
2019-03-21 13:40:00 -05:00
};