Struct rustc_type_ir::search_graph::NestedGoals

struct NestedGoals<X: Cx> {
    nested_goals: HashMap<X::Input, UsageKind>,
}

The nested goals of each stack entry and the path from the stack entry to that nested goal.

We only start tracking nested goals once we’ve either encountered overflow or a solver cycle. This is a performance optimization to avoid tracking nested goals on the happy path.

We use nested goals for two reasons:

• when rebasing provisional cache entries
• when checking whether we have to ignore a global cache entry as reevaluating it would encounter a cycle or use a provisional cache entry.

We need to disable the global cache if using it would hide a cycle, as cycles can impact behavior. The cycle ABA may have different final results from a the cycle BAB depending on the cycle root.

Fields

nested_goals: HashMap<X::Input, UsageKind>

Implementations

impl<X: Cx> NestedGoals<X>

fn is_empty(&self) -> bool

fn insert(&mut self, input: X::Input, path_from_entry: UsageKind)

fn merge(&mut self, nested_goals: &NestedGoals<X>)

fn extend_from_child( &mut self, step_kind: PathKind, nested_goals: &NestedGoals<X>, )

Adds the nested goals of a nested goal, given that the path step_kind from this goal to the parent goal.

If the path from this goal to the nested goal is inductive, the paths from this goal to all nested goals of that nested goal are also inductive. Otherwise the paths are the same as for the child.

fn iter(&self) -> impl Iterator<Item = (X::Input, UsageKind)> + '_

fn get(&self, input: X::Input) -> Option<UsageKind>

fn contains(&self, input: X::Input) -> bool

Trait Implementations

impl<X> Debug for NestedGoals<X>

where X: Cx,

fn fmt(&self, __f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<X> Default for NestedGoals<X>

where X: Cx,

fn default() -> Self

Returns the “default value” for a type.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 32 bytes