800 lines
31 KiB
Rust
800 lines
31 KiB
Rust
//! Validation of patterns/matches.
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mod check_match;
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mod const_to_pat;
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mod deconstruct_pat;
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mod usefulness;
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pub(crate) use self::check_match::check_match;
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use crate::thir::util::UserAnnotatedTyHelpers;
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use rustc_errors::struct_span_err;
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use rustc_hir as hir;
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use rustc_hir::def::{CtorOf, DefKind, Res};
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use rustc_hir::pat_util::EnumerateAndAdjustIterator;
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use rustc_hir::RangeEnd;
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use rustc_index::vec::Idx;
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use rustc_middle::mir::interpret::{get_slice_bytes, ConstValue};
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use rustc_middle::mir::interpret::{ErrorHandled, LitToConstError, LitToConstInput};
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use rustc_middle::mir::UserTypeProjection;
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use rustc_middle::mir::{BorrowKind, Field, Mutability};
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use rustc_middle::thir::{Ascription, BindingMode, FieldPat, Pat, PatKind, PatRange, PatTyProj};
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use rustc_middle::ty::subst::{GenericArg, SubstsRef};
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use rustc_middle::ty::{self, AdtDef, ConstKind, DefIdTree, Region, Ty, TyCtxt, UserType};
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use rustc_span::{Span, Symbol};
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use std::cmp::Ordering;
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#[derive(Clone, Debug)]
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crate enum PatternError {
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AssocConstInPattern(Span),
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ConstParamInPattern(Span),
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StaticInPattern(Span),
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NonConstPath(Span),
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}
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crate struct PatCtxt<'a, 'tcx> {
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crate tcx: TyCtxt<'tcx>,
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crate param_env: ty::ParamEnv<'tcx>,
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crate typeck_results: &'a ty::TypeckResults<'tcx>,
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crate errors: Vec<PatternError>,
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include_lint_checks: bool,
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}
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crate fn pat_from_hir<'a, 'tcx>(
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tcx: TyCtxt<'tcx>,
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param_env: ty::ParamEnv<'tcx>,
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typeck_results: &'a ty::TypeckResults<'tcx>,
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pat: &'tcx hir::Pat<'tcx>,
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) -> Pat<'tcx> {
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let mut pcx = PatCtxt::new(tcx, param_env, typeck_results);
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let result = pcx.lower_pattern(pat);
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if !pcx.errors.is_empty() {
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let msg = format!("encountered errors lowering pattern: {:?}", pcx.errors);
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tcx.sess.delay_span_bug(pat.span, &msg);
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}
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debug!("pat_from_hir({:?}) = {:?}", pat, result);
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result
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}
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impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
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crate fn new(
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tcx: TyCtxt<'tcx>,
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param_env: ty::ParamEnv<'tcx>,
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typeck_results: &'a ty::TypeckResults<'tcx>,
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) -> Self {
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PatCtxt { tcx, param_env, typeck_results, errors: vec![], include_lint_checks: false }
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}
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crate fn include_lint_checks(&mut self) -> &mut Self {
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self.include_lint_checks = true;
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self
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}
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crate fn lower_pattern(&mut self, pat: &'tcx hir::Pat<'tcx>) -> Pat<'tcx> {
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// When implicit dereferences have been inserted in this pattern, the unadjusted lowered
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// pattern has the type that results *after* dereferencing. For example, in this code:
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//
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// ```
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// match &&Some(0i32) {
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// Some(n) => { ... },
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// _ => { ... },
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// }
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// ```
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//
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// the type assigned to `Some(n)` in `unadjusted_pat` would be `Option<i32>` (this is
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// determined in rustc_typeck::check::match). The adjustments would be
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//
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// `vec![&&Option<i32>, &Option<i32>]`.
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//
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// Applying the adjustments, we want to instead output `&&Some(n)` (as a THIR pattern). So
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// we wrap the unadjusted pattern in `PatKind::Deref` repeatedly, consuming the
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// adjustments in *reverse order* (last-in-first-out, so that the last `Deref` inserted
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// gets the least-dereferenced type).
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let unadjusted_pat = self.lower_pattern_unadjusted(pat);
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self.typeck_results.pat_adjustments().get(pat.hir_id).unwrap_or(&vec![]).iter().rev().fold(
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unadjusted_pat,
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|pat, ref_ty| {
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debug!("{:?}: wrapping pattern with type {:?}", pat, ref_ty);
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Pat {
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span: pat.span,
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ty: *ref_ty,
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kind: Box::new(PatKind::Deref { subpattern: pat }),
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}
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},
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)
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}
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fn lower_range_expr(
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&mut self,
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expr: &'tcx hir::Expr<'tcx>,
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) -> (PatKind<'tcx>, Option<Ascription<'tcx>>) {
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match self.lower_lit(expr) {
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PatKind::AscribeUserType { ascription, subpattern: Pat { kind: box kind, .. } } => {
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(kind, Some(ascription))
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}
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kind => (kind, None),
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}
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}
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fn lower_pattern_range(
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&mut self,
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ty: Ty<'tcx>,
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lo: ty::Const<'tcx>,
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hi: ty::Const<'tcx>,
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end: RangeEnd,
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span: Span,
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) -> PatKind<'tcx> {
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assert_eq!(lo.ty(), ty);
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assert_eq!(hi.ty(), ty);
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let cmp = compare_const_vals(self.tcx, lo, hi, self.param_env, ty);
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match (end, cmp) {
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// `x..y` where `x < y`.
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// Non-empty because the range includes at least `x`.
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(RangeEnd::Excluded, Some(Ordering::Less)) => PatKind::Range(PatRange { lo, hi, end }),
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// `x..y` where `x >= y`. The range is empty => error.
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(RangeEnd::Excluded, _) => {
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struct_span_err!(
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self.tcx.sess,
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span,
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E0579,
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"lower range bound must be less than upper"
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)
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.emit();
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PatKind::Wild
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}
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// `x..=y` where `x == y`.
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(RangeEnd::Included, Some(Ordering::Equal)) => PatKind::Constant { value: lo },
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// `x..=y` where `x < y`.
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(RangeEnd::Included, Some(Ordering::Less)) => PatKind::Range(PatRange { lo, hi, end }),
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// `x..=y` where `x > y` hence the range is empty => error.
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(RangeEnd::Included, _) => {
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let mut err = struct_span_err!(
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self.tcx.sess,
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span,
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E0030,
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"lower range bound must be less than or equal to upper"
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);
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err.span_label(span, "lower bound larger than upper bound");
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if self.tcx.sess.teach(&err.get_code().unwrap()) {
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err.note(
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"When matching against a range, the compiler \
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verifies that the range is non-empty. Range \
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patterns include both end-points, so this is \
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equivalent to requiring the start of the range \
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to be less than or equal to the end of the range.",
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);
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}
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err.emit();
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PatKind::Wild
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}
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}
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}
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fn normalize_range_pattern_ends(
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&self,
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ty: Ty<'tcx>,
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lo: Option<&PatKind<'tcx>>,
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hi: Option<&PatKind<'tcx>>,
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) -> Option<(ty::Const<'tcx>, ty::Const<'tcx>)> {
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match (lo, hi) {
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(Some(PatKind::Constant { value: lo }), Some(PatKind::Constant { value: hi })) => {
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Some((*lo, *hi))
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}
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(Some(PatKind::Constant { value: lo }), None) => {
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Some((*lo, ty.numeric_max_val(self.tcx)?))
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}
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(None, Some(PatKind::Constant { value: hi })) => {
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Some((ty.numeric_min_val(self.tcx)?, *hi))
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}
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_ => None,
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}
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}
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fn lower_pattern_unadjusted(&mut self, pat: &'tcx hir::Pat<'tcx>) -> Pat<'tcx> {
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let mut ty = self.typeck_results.node_type(pat.hir_id);
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let kind = match pat.kind {
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hir::PatKind::Wild => PatKind::Wild,
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hir::PatKind::Lit(value) => self.lower_lit(value),
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hir::PatKind::Range(ref lo_expr, ref hi_expr, end) => {
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let (lo_expr, hi_expr) = (lo_expr.as_deref(), hi_expr.as_deref());
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let lo_span = lo_expr.map_or(pat.span, |e| e.span);
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let lo = lo_expr.map(|e| self.lower_range_expr(e));
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let hi = hi_expr.map(|e| self.lower_range_expr(e));
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let (lp, hp) = (lo.as_ref().map(|x| &x.0), hi.as_ref().map(|x| &x.0));
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let mut kind = match self.normalize_range_pattern_ends(ty, lp, hp) {
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Some((lc, hc)) => self.lower_pattern_range(ty, lc, hc, end, lo_span),
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None => {
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let msg = &format!(
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"found bad range pattern `{:?}` outside of error recovery",
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(&lo, &hi),
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);
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self.tcx.sess.delay_span_bug(pat.span, msg);
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PatKind::Wild
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}
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};
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// If we are handling a range with associated constants (e.g.
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// `Foo::<'a>::A..=Foo::B`), we need to put the ascriptions for the associated
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// constants somewhere. Have them on the range pattern.
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for end in &[lo, hi] {
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if let Some((_, Some(ascription))) = end {
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let subpattern = Pat { span: pat.span, ty, kind: Box::new(kind) };
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kind = PatKind::AscribeUserType { ascription: *ascription, subpattern };
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}
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}
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kind
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}
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hir::PatKind::Path(ref qpath) => {
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return self.lower_path(qpath, pat.hir_id, pat.span);
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}
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hir::PatKind::Ref(ref subpattern, _) | hir::PatKind::Box(ref subpattern) => {
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PatKind::Deref { subpattern: self.lower_pattern(subpattern) }
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}
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hir::PatKind::Slice(ref prefix, ref slice, ref suffix) => {
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self.slice_or_array_pattern(pat.span, ty, prefix, slice, suffix)
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}
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hir::PatKind::Tuple(ref pats, ddpos) => {
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let ty::Tuple(ref tys) = ty.kind() else {
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span_bug!(pat.span, "unexpected type for tuple pattern: {:?}", ty);
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};
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let subpatterns = self.lower_tuple_subpats(pats, tys.len(), ddpos);
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PatKind::Leaf { subpatterns }
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}
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hir::PatKind::Binding(_, id, ident, ref sub) => {
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let bm = *self
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.typeck_results
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.pat_binding_modes()
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.get(pat.hir_id)
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.expect("missing binding mode");
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let (mutability, mode) = match bm {
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ty::BindByValue(mutbl) => (mutbl, BindingMode::ByValue),
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ty::BindByReference(hir::Mutability::Mut) => (
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Mutability::Not,
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BindingMode::ByRef(BorrowKind::Mut { allow_two_phase_borrow: false }),
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),
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ty::BindByReference(hir::Mutability::Not) => {
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(Mutability::Not, BindingMode::ByRef(BorrowKind::Shared))
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}
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};
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// A ref x pattern is the same node used for x, and as such it has
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// x's type, which is &T, where we want T (the type being matched).
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let var_ty = ty;
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if let ty::BindByReference(_) = bm {
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if let ty::Ref(_, rty, _) = ty.kind() {
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ty = *rty;
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} else {
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bug!("`ref {}` has wrong type {}", ident, ty);
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}
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};
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PatKind::Binding {
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mutability,
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mode,
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name: ident.name,
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var: id,
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ty: var_ty,
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subpattern: self.lower_opt_pattern(sub),
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is_primary: id == pat.hir_id,
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}
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}
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hir::PatKind::TupleStruct(ref qpath, ref pats, ddpos) => {
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let res = self.typeck_results.qpath_res(qpath, pat.hir_id);
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let ty::Adt(adt_def, _) = ty.kind() else {
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span_bug!(pat.span, "tuple struct pattern not applied to an ADT {:?}", ty);
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};
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let variant_def = adt_def.variant_of_res(res);
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let subpatterns = self.lower_tuple_subpats(pats, variant_def.fields.len(), ddpos);
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self.lower_variant_or_leaf(res, pat.hir_id, pat.span, ty, subpatterns)
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}
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hir::PatKind::Struct(ref qpath, ref fields, _) => {
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let res = self.typeck_results.qpath_res(qpath, pat.hir_id);
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let subpatterns = fields
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.iter()
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.map(|field| FieldPat {
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field: Field::new(self.tcx.field_index(field.hir_id, self.typeck_results)),
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pattern: self.lower_pattern(&field.pat),
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})
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.collect();
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self.lower_variant_or_leaf(res, pat.hir_id, pat.span, ty, subpatterns)
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}
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hir::PatKind::Or(ref pats) => PatKind::Or { pats: self.lower_patterns(pats) },
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};
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Pat { span: pat.span, ty, kind: Box::new(kind) }
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}
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fn lower_tuple_subpats(
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&mut self,
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pats: &'tcx [hir::Pat<'tcx>],
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expected_len: usize,
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gap_pos: Option<usize>,
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) -> Vec<FieldPat<'tcx>> {
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pats.iter()
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.enumerate_and_adjust(expected_len, gap_pos)
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.map(|(i, subpattern)| FieldPat {
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field: Field::new(i),
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pattern: self.lower_pattern(subpattern),
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})
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.collect()
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}
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fn lower_patterns(&mut self, pats: &'tcx [hir::Pat<'tcx>]) -> Vec<Pat<'tcx>> {
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pats.iter().map(|p| self.lower_pattern(p)).collect()
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}
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fn lower_opt_pattern(&mut self, pat: &'tcx Option<&'tcx hir::Pat<'tcx>>) -> Option<Pat<'tcx>> {
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pat.as_ref().map(|p| self.lower_pattern(p))
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}
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fn slice_or_array_pattern(
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&mut self,
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span: Span,
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ty: Ty<'tcx>,
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prefix: &'tcx [hir::Pat<'tcx>],
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slice: &'tcx Option<&'tcx hir::Pat<'tcx>>,
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suffix: &'tcx [hir::Pat<'tcx>],
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) -> PatKind<'tcx> {
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let prefix = self.lower_patterns(prefix);
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let slice = self.lower_opt_pattern(slice);
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let suffix = self.lower_patterns(suffix);
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match ty.kind() {
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// Matching a slice, `[T]`.
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ty::Slice(..) => PatKind::Slice { prefix, slice, suffix },
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// Fixed-length array, `[T; len]`.
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ty::Array(_, len) => {
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let len = len.eval_usize(self.tcx, self.param_env);
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assert!(len >= prefix.len() as u64 + suffix.len() as u64);
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PatKind::Array { prefix, slice, suffix }
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}
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_ => span_bug!(span, "bad slice pattern type {:?}", ty),
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}
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}
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fn lower_variant_or_leaf(
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&mut self,
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res: Res,
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hir_id: hir::HirId,
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span: Span,
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ty: Ty<'tcx>,
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subpatterns: Vec<FieldPat<'tcx>>,
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) -> PatKind<'tcx> {
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let res = match res {
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Res::Def(DefKind::Ctor(CtorOf::Variant, ..), variant_ctor_id) => {
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let variant_id = self.tcx.parent(variant_ctor_id).unwrap();
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Res::Def(DefKind::Variant, variant_id)
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}
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res => res,
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};
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let mut kind = match res {
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Res::Def(DefKind::Variant, variant_id) => {
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let enum_id = self.tcx.parent(variant_id).unwrap();
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let adt_def = self.tcx.adt_def(enum_id);
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if adt_def.is_enum() {
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let substs = match ty.kind() {
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ty::Adt(_, substs) | ty::FnDef(_, substs) => substs,
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ty::Error(_) => {
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// Avoid ICE (#50585)
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return PatKind::Wild;
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}
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_ => bug!("inappropriate type for def: {:?}", ty),
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};
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PatKind::Variant {
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adt_def,
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substs,
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variant_index: adt_def.variant_index_with_id(variant_id),
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subpatterns,
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}
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} else {
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PatKind::Leaf { subpatterns }
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}
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}
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Res::Def(
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DefKind::Struct
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| DefKind::Ctor(CtorOf::Struct, ..)
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| DefKind::Union
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| DefKind::TyAlias
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| DefKind::AssocTy,
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_,
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)
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| Res::SelfTy { .. }
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| Res::SelfCtor(..) => PatKind::Leaf { subpatterns },
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_ => {
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let pattern_error = match res {
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Res::Def(DefKind::ConstParam, _) => PatternError::ConstParamInPattern(span),
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Res::Def(DefKind::Static(_), _) => PatternError::StaticInPattern(span),
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_ => PatternError::NonConstPath(span),
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};
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self.errors.push(pattern_error);
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PatKind::Wild
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}
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};
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if let Some(user_ty) = self.user_substs_applied_to_ty_of_hir_id(hir_id) {
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debug!("lower_variant_or_leaf: kind={:?} user_ty={:?} span={:?}", kind, user_ty, span);
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kind = PatKind::AscribeUserType {
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subpattern: Pat { span, ty, kind: Box::new(kind) },
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ascription: Ascription {
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user_ty: PatTyProj::from_user_type(user_ty),
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user_ty_span: span,
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variance: ty::Variance::Covariant,
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},
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};
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}
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kind
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}
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/// Takes a HIR Path. If the path is a constant, evaluates it and feeds
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/// it to `const_to_pat`. Any other path (like enum variants without fields)
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/// is converted to the corresponding pattern via `lower_variant_or_leaf`.
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fn lower_path(&mut self, qpath: &hir::QPath<'_>, id: hir::HirId, span: Span) -> Pat<'tcx> {
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let ty = self.typeck_results.node_type(id);
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let res = self.typeck_results.qpath_res(qpath, id);
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let pat_from_kind = |kind| Pat { span, ty, kind: Box::new(kind) };
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let (def_id, is_associated_const) = match res {
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Res::Def(DefKind::Const, def_id) => (def_id, false),
|
|
Res::Def(DefKind::AssocConst, def_id) => (def_id, true),
|
|
|
|
_ => return pat_from_kind(self.lower_variant_or_leaf(res, id, span, ty, vec![])),
|
|
};
|
|
|
|
// Use `Reveal::All` here because patterns are always monomorphic even if their function
|
|
// isn't.
|
|
let param_env_reveal_all = self.param_env.with_reveal_all_normalized(self.tcx);
|
|
let substs = self.typeck_results.node_substs(id);
|
|
let instance = match ty::Instance::resolve(self.tcx, param_env_reveal_all, def_id, substs) {
|
|
Ok(Some(i)) => i,
|
|
Ok(None) => {
|
|
// It should be assoc consts if there's no error but we cannot resolve it.
|
|
debug_assert!(is_associated_const);
|
|
|
|
self.errors.push(PatternError::AssocConstInPattern(span));
|
|
|
|
return pat_from_kind(PatKind::Wild);
|
|
}
|
|
|
|
Err(_) => {
|
|
self.tcx.sess.span_err(span, "could not evaluate constant pattern");
|
|
return pat_from_kind(PatKind::Wild);
|
|
}
|
|
};
|
|
|
|
// `mir_const_qualif` must be called with the `DefId` of the item where the const is
|
|
// defined, not where it is declared. The difference is significant for associated
|
|
// constants.
|
|
let mir_structural_match_violation = self.tcx.mir_const_qualif(instance.def_id()).custom_eq;
|
|
debug!("mir_structural_match_violation({:?}) -> {}", qpath, mir_structural_match_violation);
|
|
|
|
match self.tcx.const_eval_instance(param_env_reveal_all, instance, Some(span)) {
|
|
Ok(value) => {
|
|
let const_ = ty::Const::from_value(self.tcx, value, ty);
|
|
let pattern = self.const_to_pat(const_, id, span, mir_structural_match_violation);
|
|
|
|
if !is_associated_const {
|
|
return pattern;
|
|
}
|
|
|
|
let user_provided_types = self.typeck_results().user_provided_types();
|
|
if let Some(u_ty) = user_provided_types.get(id) {
|
|
let user_ty = PatTyProj::from_user_type(*u_ty);
|
|
Pat {
|
|
span,
|
|
kind: Box::new(PatKind::AscribeUserType {
|
|
subpattern: pattern,
|
|
ascription: Ascription {
|
|
/// Note that use `Contravariant` here. See the
|
|
/// `variance` field documentation for details.
|
|
variance: ty::Variance::Contravariant,
|
|
user_ty,
|
|
user_ty_span: span,
|
|
},
|
|
}),
|
|
ty: const_.ty(),
|
|
}
|
|
} else {
|
|
pattern
|
|
}
|
|
}
|
|
Err(ErrorHandled::TooGeneric) => {
|
|
// While `Reported | Linted` cases will have diagnostics emitted already
|
|
// it is not true for TooGeneric case, so we need to give user more information.
|
|
self.tcx.sess.span_err(span, "constant pattern depends on a generic parameter");
|
|
pat_from_kind(PatKind::Wild)
|
|
}
|
|
Err(_) => {
|
|
self.tcx.sess.span_err(span, "could not evaluate constant pattern");
|
|
pat_from_kind(PatKind::Wild)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Converts inline const patterns.
|
|
fn lower_inline_const(
|
|
&mut self,
|
|
anon_const: &'tcx hir::AnonConst,
|
|
id: hir::HirId,
|
|
span: Span,
|
|
) -> PatKind<'tcx> {
|
|
let anon_const_def_id = self.tcx.hir().local_def_id(anon_const.hir_id);
|
|
let value = ty::Const::from_inline_const(self.tcx, anon_const_def_id);
|
|
|
|
// Evaluate early like we do in `lower_path`.
|
|
let value = value.eval(self.tcx, self.param_env);
|
|
|
|
match value.val() {
|
|
ConstKind::Param(_) => {
|
|
self.errors.push(PatternError::ConstParamInPattern(span));
|
|
return PatKind::Wild;
|
|
}
|
|
ConstKind::Unevaluated(_) => {
|
|
// If we land here it means the const can't be evaluated because it's `TooGeneric`.
|
|
self.tcx.sess.span_err(span, "constant pattern depends on a generic parameter");
|
|
return PatKind::Wild;
|
|
}
|
|
_ => (),
|
|
}
|
|
|
|
*self.const_to_pat(value, id, span, false).kind
|
|
}
|
|
|
|
/// Converts literals, paths and negation of literals to patterns.
|
|
/// The special case for negation exists to allow things like `-128_i8`
|
|
/// which would overflow if we tried to evaluate `128_i8` and then negate
|
|
/// afterwards.
|
|
fn lower_lit(&mut self, expr: &'tcx hir::Expr<'tcx>) -> PatKind<'tcx> {
|
|
let (lit, neg) = match expr.kind {
|
|
hir::ExprKind::Path(ref qpath) => {
|
|
return *self.lower_path(qpath, expr.hir_id, expr.span).kind;
|
|
}
|
|
hir::ExprKind::ConstBlock(ref anon_const) => {
|
|
return self.lower_inline_const(anon_const, expr.hir_id, expr.span);
|
|
}
|
|
hir::ExprKind::Lit(ref lit) => (lit, false),
|
|
hir::ExprKind::Unary(hir::UnOp::Neg, ref expr) => {
|
|
let hir::ExprKind::Lit(ref lit) = expr.kind else {
|
|
span_bug!(expr.span, "not a literal: {:?}", expr);
|
|
};
|
|
(lit, true)
|
|
}
|
|
_ => span_bug!(expr.span, "not a literal: {:?}", expr),
|
|
};
|
|
|
|
let lit_input =
|
|
LitToConstInput { lit: &lit.node, ty: self.typeck_results.expr_ty(expr), neg };
|
|
match self.tcx.at(expr.span).lit_to_const(lit_input) {
|
|
Ok(constant) => *self.const_to_pat(constant, expr.hir_id, lit.span, false).kind,
|
|
Err(LitToConstError::Reported) => PatKind::Wild,
|
|
Err(LitToConstError::TypeError) => bug!("lower_lit: had type error"),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'tcx> UserAnnotatedTyHelpers<'tcx> for PatCtxt<'_, 'tcx> {
|
|
fn tcx(&self) -> TyCtxt<'tcx> {
|
|
self.tcx
|
|
}
|
|
|
|
fn typeck_results(&self) -> &ty::TypeckResults<'tcx> {
|
|
self.typeck_results
|
|
}
|
|
}
|
|
|
|
crate trait PatternFoldable<'tcx>: Sized {
|
|
fn fold_with<F: PatternFolder<'tcx>>(&self, folder: &mut F) -> Self {
|
|
self.super_fold_with(folder)
|
|
}
|
|
|
|
fn super_fold_with<F: PatternFolder<'tcx>>(&self, folder: &mut F) -> Self;
|
|
}
|
|
|
|
crate trait PatternFolder<'tcx>: Sized {
|
|
fn fold_pattern(&mut self, pattern: &Pat<'tcx>) -> Pat<'tcx> {
|
|
pattern.super_fold_with(self)
|
|
}
|
|
|
|
fn fold_pattern_kind(&mut self, kind: &PatKind<'tcx>) -> PatKind<'tcx> {
|
|
kind.super_fold_with(self)
|
|
}
|
|
}
|
|
|
|
impl<'tcx, T: PatternFoldable<'tcx>> PatternFoldable<'tcx> for Box<T> {
|
|
fn super_fold_with<F: PatternFolder<'tcx>>(&self, folder: &mut F) -> Self {
|
|
let content: T = (**self).fold_with(folder);
|
|
Box::new(content)
|
|
}
|
|
}
|
|
|
|
impl<'tcx, T: PatternFoldable<'tcx>> PatternFoldable<'tcx> for Vec<T> {
|
|
fn super_fold_with<F: PatternFolder<'tcx>>(&self, folder: &mut F) -> Self {
|
|
self.iter().map(|t| t.fold_with(folder)).collect()
|
|
}
|
|
}
|
|
|
|
impl<'tcx, T: PatternFoldable<'tcx>> PatternFoldable<'tcx> for Option<T> {
|
|
fn super_fold_with<F: PatternFolder<'tcx>>(&self, folder: &mut F) -> Self {
|
|
self.as_ref().map(|t| t.fold_with(folder))
|
|
}
|
|
}
|
|
|
|
macro_rules! CloneImpls {
|
|
(<$lt_tcx:tt> $($ty:ty),+) => {
|
|
$(
|
|
impl<$lt_tcx> PatternFoldable<$lt_tcx> for $ty {
|
|
fn super_fold_with<F: PatternFolder<$lt_tcx>>(&self, _: &mut F) -> Self {
|
|
Clone::clone(self)
|
|
}
|
|
}
|
|
)+
|
|
}
|
|
}
|
|
|
|
CloneImpls! { <'tcx>
|
|
Span, Field, Mutability, Symbol, hir::HirId, usize, ty::Const<'tcx>,
|
|
Region<'tcx>, Ty<'tcx>, BindingMode, AdtDef<'tcx>,
|
|
SubstsRef<'tcx>, &'tcx GenericArg<'tcx>, UserType<'tcx>,
|
|
UserTypeProjection, PatTyProj<'tcx>
|
|
}
|
|
|
|
impl<'tcx> PatternFoldable<'tcx> for FieldPat<'tcx> {
|
|
fn super_fold_with<F: PatternFolder<'tcx>>(&self, folder: &mut F) -> Self {
|
|
FieldPat { field: self.field.fold_with(folder), pattern: self.pattern.fold_with(folder) }
|
|
}
|
|
}
|
|
|
|
impl<'tcx> PatternFoldable<'tcx> for Pat<'tcx> {
|
|
fn fold_with<F: PatternFolder<'tcx>>(&self, folder: &mut F) -> Self {
|
|
folder.fold_pattern(self)
|
|
}
|
|
|
|
fn super_fold_with<F: PatternFolder<'tcx>>(&self, folder: &mut F) -> Self {
|
|
Pat {
|
|
ty: self.ty.fold_with(folder),
|
|
span: self.span.fold_with(folder),
|
|
kind: self.kind.fold_with(folder),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'tcx> PatternFoldable<'tcx> for PatKind<'tcx> {
|
|
fn fold_with<F: PatternFolder<'tcx>>(&self, folder: &mut F) -> Self {
|
|
folder.fold_pattern_kind(self)
|
|
}
|
|
|
|
fn super_fold_with<F: PatternFolder<'tcx>>(&self, folder: &mut F) -> Self {
|
|
match *self {
|
|
PatKind::Wild => PatKind::Wild,
|
|
PatKind::AscribeUserType {
|
|
ref subpattern,
|
|
ascription: Ascription { variance, ref user_ty, user_ty_span },
|
|
} => PatKind::AscribeUserType {
|
|
subpattern: subpattern.fold_with(folder),
|
|
ascription: Ascription {
|
|
user_ty: user_ty.fold_with(folder),
|
|
variance,
|
|
user_ty_span,
|
|
},
|
|
},
|
|
PatKind::Binding { mutability, name, mode, var, ty, ref subpattern, is_primary } => {
|
|
PatKind::Binding {
|
|
mutability: mutability.fold_with(folder),
|
|
name: name.fold_with(folder),
|
|
mode: mode.fold_with(folder),
|
|
var: var.fold_with(folder),
|
|
ty: ty.fold_with(folder),
|
|
subpattern: subpattern.fold_with(folder),
|
|
is_primary,
|
|
}
|
|
}
|
|
PatKind::Variant { adt_def, substs, variant_index, ref subpatterns } => {
|
|
PatKind::Variant {
|
|
adt_def: adt_def.fold_with(folder),
|
|
substs: substs.fold_with(folder),
|
|
variant_index,
|
|
subpatterns: subpatterns.fold_with(folder),
|
|
}
|
|
}
|
|
PatKind::Leaf { ref subpatterns } => {
|
|
PatKind::Leaf { subpatterns: subpatterns.fold_with(folder) }
|
|
}
|
|
PatKind::Deref { ref subpattern } => {
|
|
PatKind::Deref { subpattern: subpattern.fold_with(folder) }
|
|
}
|
|
PatKind::Constant { value } => PatKind::Constant { value },
|
|
PatKind::Range(range) => PatKind::Range(range),
|
|
PatKind::Slice { ref prefix, ref slice, ref suffix } => PatKind::Slice {
|
|
prefix: prefix.fold_with(folder),
|
|
slice: slice.fold_with(folder),
|
|
suffix: suffix.fold_with(folder),
|
|
},
|
|
PatKind::Array { ref prefix, ref slice, ref suffix } => PatKind::Array {
|
|
prefix: prefix.fold_with(folder),
|
|
slice: slice.fold_with(folder),
|
|
suffix: suffix.fold_with(folder),
|
|
},
|
|
PatKind::Or { ref pats } => PatKind::Or { pats: pats.fold_with(folder) },
|
|
}
|
|
}
|
|
}
|
|
|
|
#[instrument(skip(tcx), level = "debug")]
|
|
crate fn compare_const_vals<'tcx>(
|
|
tcx: TyCtxt<'tcx>,
|
|
a: ty::Const<'tcx>,
|
|
b: ty::Const<'tcx>,
|
|
param_env: ty::ParamEnv<'tcx>,
|
|
ty: Ty<'tcx>,
|
|
) -> Option<Ordering> {
|
|
let from_bool = |v: bool| v.then_some(Ordering::Equal);
|
|
|
|
let fallback = || from_bool(a == b);
|
|
|
|
// Use the fallback if any type differs
|
|
if a.ty() != b.ty() || a.ty() != ty {
|
|
return fallback();
|
|
}
|
|
|
|
// Early return for equal constants (so e.g. references to ZSTs can be compared, even if they
|
|
// are just integer addresses).
|
|
if a.val() == b.val() {
|
|
return from_bool(true);
|
|
}
|
|
|
|
let a_bits = a.try_eval_bits(tcx, param_env, ty);
|
|
let b_bits = b.try_eval_bits(tcx, param_env, ty);
|
|
|
|
if let (Some(a), Some(b)) = (a_bits, b_bits) {
|
|
use rustc_apfloat::Float;
|
|
return match *ty.kind() {
|
|
ty::Float(ty::FloatTy::F32) => {
|
|
let l = rustc_apfloat::ieee::Single::from_bits(a);
|
|
let r = rustc_apfloat::ieee::Single::from_bits(b);
|
|
l.partial_cmp(&r)
|
|
}
|
|
ty::Float(ty::FloatTy::F64) => {
|
|
let l = rustc_apfloat::ieee::Double::from_bits(a);
|
|
let r = rustc_apfloat::ieee::Double::from_bits(b);
|
|
l.partial_cmp(&r)
|
|
}
|
|
ty::Int(ity) => {
|
|
use rustc_middle::ty::layout::IntegerExt;
|
|
let size = rustc_target::abi::Integer::from_int_ty(&tcx, ity).size();
|
|
let a = size.sign_extend(a);
|
|
let b = size.sign_extend(b);
|
|
Some((a as i128).cmp(&(b as i128)))
|
|
}
|
|
_ => Some(a.cmp(&b)),
|
|
};
|
|
}
|
|
|
|
if let ty::Str = ty.kind() && let (
|
|
ty::ConstKind::Value(a_val @ ConstValue::Slice { .. }),
|
|
ty::ConstKind::Value(b_val @ ConstValue::Slice { .. }),
|
|
) = (a.val(), b.val())
|
|
{
|
|
let a_bytes = get_slice_bytes(&tcx, a_val);
|
|
let b_bytes = get_slice_bytes(&tcx, b_val);
|
|
return from_bool(a_bytes == b_bytes);
|
|
}
|
|
fallback()
|
|
}
|