Module rustc_hir_analysis::check::generator_interior::drop_ranges

Drop range analysis finds the portions of the tree where a value is guaranteed to be dropped (i.e. moved, uninitialized, etc.). This is used to exclude the types of those values from the generator type. See InteriorVisitor::record for where the results of this analysis are used.

There are three phases to this analysis:

1. Use ExprUseVisitor to identify the interesting values that are consumed and borrowed.
2. Use DropRangeVisitor to find where the interesting values are dropped or reinitialized, and also build a control flow graph.
3. Use DropRanges::propagate_to_fixpoint to flow the dropped/reinitialized information through the CFG and find the exact points where we know a value is definitely dropped.

The end result is a data structure that maps the post-order index of each node in the HIR tree to a set of values that are known to be dropped at that location.

Modules

cfg_build 🔒

cfg_propagate 🔒

cfg_visualize 🔒

Implementation of GraphWalk for DropRanges so we can visualize the control flow graph when needed for debugging.

record_consumed_borrow 🔒

Structs

DropRanges

DropRangesBuilder 🔒

Tracks information needed to compute drop ranges.

NodeInfo 🔒

PostOrderId

TrackedValueIndex

Enums

TrackedValue 🔒

Identifies a value whose drop state we need to track.

TrackedValueConversionError 🔒

Represents a reason why we might not be able to convert a HirId or Place into a tracked value.

Functions

compute_drop_ranges

for_each_consumable 🔒

Applies f to consumable node in the HIR subtree pointed to by place.