Struct rustc_mir_build::thir::pattern::usefulness::PatternColumn

struct PatternColumn<'p, 'tcx> {
    patterns: Vec<&'p DeconstructedPat<'p, 'tcx>>,
}

A column of patterns in the matrix, where a column is the intuitive notion of “subpatterns that inspect the same subvalue”. This is used to traverse patterns column-by-column for lints. Despite similarities with is_useful, this is a different traversal. Notably this is linear in the depth of patterns, whereas is_useful is worst-case exponential (exhaustiveness is NP-complete).

Fields

patterns: Vec<&'p DeconstructedPat<'p, 'tcx>>

Implementations

impl<'p, 'tcx> PatternColumn<'p, 'tcx>

fn new(patterns: Vec<&'p DeconstructedPat<'p, 'tcx>>) -> Self

fn is_empty(&self) -> bool

fn head_ty(&self) -> Option<Ty<'tcx>>

fn analyze_ctors( &self, pcx: &PatCtxt<'_, 'p, 'tcx> ) -> SplitConstructorSet<'tcx>

fn iter<'a>( &'a self ) -> impl Iterator<Item = &'p DeconstructedPat<'p, 'tcx>> + Captures<'a>

fn specialize( &self, pcx: &PatCtxt<'_, 'p, 'tcx>, ctor: &Constructor<'tcx> ) -> Vec<Self>

Does specialization: given a constructor, this takes the patterns from the column that match the constructor, and outputs their fields. This returns one column per field of the constructor. The normally all have the same length (the number of patterns in self that matched ctor), except that we expand or-patterns which may change the lengths.

Trait Implementations

impl<'p, 'tcx> Debug for PatternColumn<'p, 'tcx>

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

Formats the value using the given formatter.

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: 24 bytes