Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/hir-ty/src/mir/lower/pattern_matching.rs')
| -rw-r--r-- | crates/hir-ty/src/mir/lower/pattern_matching.rs | 98 |
1 files changed, 76 insertions, 22 deletions
diff --git a/crates/hir-ty/src/mir/lower/pattern_matching.rs b/crates/hir-ty/src/mir/lower/pattern_matching.rs index b1c0d1f2b3..2ffea34c85 100644 --- a/crates/hir-ty/src/mir/lower/pattern_matching.rs +++ b/crates/hir-ty/src/mir/lower/pattern_matching.rs @@ -1,6 +1,6 @@ //! MIR lowering for patterns -use hir_def::{hir::LiteralOrConst, resolver::HasResolver, AssocItemId}; +use hir_def::{hir::LiteralOrConst, AssocItemId}; use crate::{ mir::{ @@ -46,6 +46,8 @@ enum MatchingMode { Check, /// Assume that this pattern matches, fill bindings Bind, + /// Assume that this pattern matches, assign to existing variables. + Assign, } impl MirLowerCtx<'_> { @@ -82,6 +84,17 @@ impl MirLowerCtx<'_> { Ok((current, current_else)) } + pub(super) fn pattern_match_assignment( + &mut self, + current: BasicBlockId, + value: Place, + pattern: PatId, + ) -> Result<BasicBlockId> { + let (current, _) = + self.pattern_match_inner(current, None, value, pattern, MatchingMode::Assign)?; + Ok(current) + } + pub(super) fn match_self_param( &mut self, id: BindingId, @@ -155,14 +168,8 @@ impl MirLowerCtx<'_> { *pat, MatchingMode::Check, )?; - if mode == MatchingMode::Bind { - (next, _) = self.pattern_match_inner( - next, - None, - cond_place, - *pat, - MatchingMode::Bind, - )?; + if mode != MatchingMode::Check { + (next, _) = self.pattern_match_inner(next, None, cond_place, *pat, mode)?; } self.set_goto(next, then_target, pattern.into()); match next_else { @@ -176,11 +183,11 @@ impl MirLowerCtx<'_> { } } if !finished { - if mode == MatchingMode::Bind { - self.set_terminator(current, TerminatorKind::Unreachable, pattern.into()); - } else { + if mode == MatchingMode::Check { let ce = *current_else.get_or_insert_with(|| self.new_basic_block()); self.set_goto(current, ce, pattern.into()); + } else { + self.set_terminator(current, TerminatorKind::Unreachable, pattern.into()); } } (then_target, current_else) @@ -300,7 +307,7 @@ impl MirLowerCtx<'_> { self.pattern_match_inner(current, current_else, next_place, pat, mode)?; } if let &Some(slice) = slice { - if mode == MatchingMode::Bind { + if mode != MatchingMode::Check { if let Pat::Bind { id, subpat: _ } = self.body[slice] { let next_place = cond_place.project( ProjectionElem::Subslice { @@ -342,17 +349,36 @@ impl MirLowerCtx<'_> { mode, )?, None => { - // The path is not a variant, so it is a const + let unresolved_name = || { + MirLowerError::unresolved_path(self.db, p, self.edition(), &self.body.types) + }; + let hygiene = self.body.pat_path_hygiene(pattern); + let pr = self + .resolver + .resolve_path_in_value_ns(self.db.upcast(), p, hygiene) + .ok_or_else(unresolved_name)?; + + if let ( + MatchingMode::Assign, + ResolveValueResult::ValueNs(ValueNs::LocalBinding(binding), _), + ) = (mode, &pr) + { + let local = self.binding_local(*binding)?; + self.push_match_assignment( + current, + local, + BindingMode::Move, + cond_place, + pattern.into(), + ); + return Ok((current, current_else)); + } + + // The path is not a variant or a local, so it is a const if mode != MatchingMode::Check { // A const don't bind anything. Only needs check. return Ok((current, current_else)); } - let unresolved_name = - || MirLowerError::unresolved_path(self.db, p, self.edition()); - let resolver = self.owner.resolver(self.db.upcast()); - let pr = resolver - .resolve_path_in_value_ns(self.db.upcast(), p) - .ok_or_else(unresolved_name)?; let (c, subst) = 'b: { if let Some(x) = self.infer.assoc_resolutions_for_pat(pattern) { if let AssocItemId::ConstId(c) = x.0 { @@ -415,7 +441,7 @@ impl MirLowerCtx<'_> { (current, current_else) = self.pattern_match_inner(current, current_else, cond_place, *subpat, mode)? } - if mode == MatchingMode::Bind { + if mode != MatchingMode::Check { let mode = self.infer.binding_modes[pattern]; self.pattern_match_binding( *id, @@ -448,6 +474,23 @@ impl MirLowerCtx<'_> { cond_place.project(ProjectionElem::Deref, &mut self.result.projection_store); self.pattern_match_inner(current, current_else, cond_place, *pat, mode)? } + &Pat::Expr(expr) => { + stdx::always!( + mode == MatchingMode::Assign, + "Pat::Expr can only come in destructuring assignments" + ); + let Some((lhs_place, current)) = self.lower_expr_as_place(current, expr, false)? + else { + return Ok((current, current_else)); + }; + self.push_assignment( + current, + lhs_place, + Operand::Copy(cond_place).into(), + expr.into(), + ); + (current, current_else) + } Pat::Box { .. } => not_supported!("box pattern"), Pat::ConstBlock(_) => not_supported!("const block pattern"), }) @@ -464,6 +507,18 @@ impl MirLowerCtx<'_> { ) -> Result<(BasicBlockId, Option<BasicBlockId>)> { let target_place = self.binding_local(id)?; self.push_storage_live(id, current)?; + self.push_match_assignment(current, target_place, mode, cond_place, span); + Ok((current, current_else)) + } + + fn push_match_assignment( + &mut self, + current: BasicBlockId, + target_place: LocalId, + mode: BindingMode, + cond_place: Place, + span: MirSpan, + ) { self.push_assignment( current, target_place.into(), @@ -476,7 +531,6 @@ impl MirLowerCtx<'_> { }, span, ); - Ok((current, current_else)) } fn pattern_match_const( |