Module syntax::feature_gate

Unstable (rustc_private)

Feature gating

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.

Structs

Features	[Unstable] A set of features to be used by later passes.
GatedCfg	[Unstable]

Enums

AttributeGate	[Unstable]
AttributeType	[Unstable]
GateIssue	[Unstable]
GatedCfgAttr	[Unstable]
UnstableFeatures	[Unstable]

Constants

EXPLAIN_ALLOW_INTERNAL_UNSTABLE	[Unstable]
EXPLAIN_ASM	[Unstable]
EXPLAIN_CONCAT_IDENTS	[Unstable]
EXPLAIN_CUSTOM_DERIVE	[Unstable]
EXPLAIN_DERIVE_UNDERSCORE	[Unstable]
EXPLAIN_LOG_SYNTAX	[Unstable]
EXPLAIN_PLACEMENT_IN	[Unstable]
EXPLAIN_TRACE_MACROS	[Unstable]
KNOWN_ATTRIBUTES	[Unstable]

Functions

check_attribute	[Unstable]
check_crate	[Unstable]
emit_feature_err	[Unstable]
get_features	[Unstable]