bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/hir-def/src/body/lower.rs')
-rw-r--r--crates/hir-def/src/body/lower.rs87
1 files changed, 74 insertions, 13 deletions
diff --git a/crates/hir-def/src/body/lower.rs b/crates/hir-def/src/body/lower.rs
index 448821d384..a93fcb3b1d 100644
--- a/crates/hir-def/src/body/lower.rs
+++ b/crates/hir-def/src/body/lower.rs
@@ -19,7 +19,7 @@ use rustc_hash::FxHashMap;
use smallvec::SmallVec;
use syntax::{
ast::{
- self, ArrayExprKind, AstChildren, HasArgList, HasLoopBody, HasName, LiteralKind,
+ self, ArrayExprKind, AstChildren, BlockExpr, HasArgList, HasLoopBody, HasName, LiteralKind,
SlicePatComponents,
},
AstNode, AstPtr, SyntaxNodePtr,
@@ -100,6 +100,7 @@ pub(super) fn lower(
_c: Count::new(),
},
expander,
+ current_try_block: None,
is_lowering_assignee_expr: false,
is_lowering_generator: false,
}
@@ -113,6 +114,7 @@ struct ExprCollector<'a> {
body: Body,
krate: CrateId,
source_map: BodySourceMap,
+ current_try_block: Option<LabelId>,
is_lowering_assignee_expr: bool,
is_lowering_generator: bool,
}
@@ -222,6 +224,10 @@ impl ExprCollector<'_> {
self.source_map.label_map.insert(src, id);
id
}
+ // FIXME: desugared labels don't have ptr, that's wrong and should be fixed somehow.
+ fn alloc_label_desugared(&mut self, label: Label) -> LabelId {
+ self.body.labels.alloc(label)
+ }
fn make_label(&mut self, label: Label, src: LabelSource) -> LabelId {
let id = self.body.labels.alloc(label);
self.source_map.label_map_back.insert(id, src);
@@ -259,13 +265,7 @@ impl ExprCollector<'_> {
self.alloc_expr(Expr::Let { pat, expr }, syntax_ptr)
}
ast::Expr::BlockExpr(e) => match e.modifier() {
- Some(ast::BlockModifier::Try(_)) => {
- self.collect_block_(e, |id, statements, tail| Expr::TryBlock {
- id,
- statements,
- tail,
- })
- }
+ Some(ast::BlockModifier::Try(_)) => self.collect_try_block(e),
Some(ast::BlockModifier::Unsafe(_)) => {
self.collect_block_(e, |id, statements, tail| Expr::Unsafe {
id,
@@ -606,6 +606,59 @@ impl ExprCollector<'_> {
})
}
+ /// Desugar `try { <stmts>; <expr> }` into `'<new_label>: { <stmts>; ::std::ops::Try::from_output(<expr>) }`,
+ /// `try { <stmts>; }` into `'<new_label>: { <stmts>; ::std::ops::Try::from_output(()) }`
+ /// and save the `<new_label>` to use it as a break target for desugaring of the `?` operator.
+ fn collect_try_block(&mut self, e: BlockExpr) -> ExprId {
+ let Some(try_from_output) = LangItem::TryTraitFromOutput.path(self.db, self.krate) else {
+ return self.alloc_expr_desugared(Expr::Missing);
+ };
+ let prev_try_block = self.current_try_block.take();
+ self.current_try_block =
+ Some(self.alloc_label_desugared(Label { name: Name::generate_new_name() }));
+ let expr_id = self.collect_block(e);
+ let callee = self.alloc_expr_desugared(Expr::Path(try_from_output));
+ let Expr::Block { label, tail, .. } = &mut self.body.exprs[expr_id] else {
+ unreachable!("It is the output of collect block");
+ };
+ *label = self.current_try_block;
+ let next_tail = match *tail {
+ Some(tail) => self.alloc_expr_desugared(Expr::Call {
+ callee,
+ args: Box::new([tail]),
+ is_assignee_expr: false,
+ }),
+ None => {
+ let unit = self.alloc_expr_desugared(Expr::Tuple {
+ exprs: Box::new([]),
+ is_assignee_expr: false,
+ });
+ self.alloc_expr_desugared(Expr::Call {
+ callee,
+ args: Box::new([unit]),
+ is_assignee_expr: false,
+ })
+ }
+ };
+ let Expr::Block { tail, .. } = &mut self.body.exprs[expr_id] else {
+ unreachable!("It is the output of collect block");
+ };
+ *tail = Some(next_tail);
+ self.current_try_block = prev_try_block;
+ expr_id
+ }
+
+ /// Desugar `ast::TryExpr` from: `<expr>?` into:
+ /// ```ignore (pseudo-rust)
+ /// match Try::branch(<expr>) {
+ /// ControlFlow::Continue(val) => val,
+ /// ControlFlow::Break(residual) =>
+ /// // If there is an enclosing `try {...}`:
+ /// break 'catch_target Try::from_residual(residual),
+ /// // Otherwise:
+ /// return Try::from_residual(residual),
+ /// }
+ /// ```
fn collect_try_operator(&mut self, syntax_ptr: AstPtr<ast::Expr>, e: ast::TryExpr) -> ExprId {
let (try_branch, cf_continue, cf_break, try_from_residual) = 'if_chain: {
if let Some(try_branch) = LangItem::TryTraitBranch.path(self.db, self.krate) {
@@ -628,7 +681,9 @@ impl ExprCollector<'_> {
Expr::Call { callee: try_branch, args: Box::new([operand]), is_assignee_expr: false },
syntax_ptr.clone(),
);
- let continue_binding = self.alloc_binding(name![v1], BindingAnnotation::Unannotated);
+ let continue_name = Name::generate_new_name();
+ let continue_binding =
+ self.alloc_binding(continue_name.clone(), BindingAnnotation::Unannotated);
let continue_bpat =
self.alloc_pat_desugared(Pat::Bind { id: continue_binding, subpat: None });
self.add_definition_to_binding(continue_binding, continue_bpat);
@@ -639,9 +694,10 @@ impl ExprCollector<'_> {
ellipsis: None,
}),
guard: None,
- expr: self.alloc_expr(Expr::Path(Path::from(name![v1])), syntax_ptr.clone()),
+ expr: self.alloc_expr(Expr::Path(Path::from(continue_name)), syntax_ptr.clone()),
};
- let break_binding = self.alloc_binding(name![v1], BindingAnnotation::Unannotated);
+ let break_name = Name::generate_new_name();
+ let break_binding = self.alloc_binding(break_name.clone(), BindingAnnotation::Unannotated);
let break_bpat = self.alloc_pat_desugared(Pat::Bind { id: break_binding, subpat: None });
self.add_definition_to_binding(break_binding, break_bpat);
let break_arm = MatchArm {
@@ -652,13 +708,18 @@ impl ExprCollector<'_> {
}),
guard: None,
expr: {
- let x = self.alloc_expr(Expr::Path(Path::from(name![v1])), syntax_ptr.clone());
+ let x = self.alloc_expr(Expr::Path(Path::from(break_name)), syntax_ptr.clone());
let callee = self.alloc_expr(Expr::Path(try_from_residual), syntax_ptr.clone());
let result = self.alloc_expr(
Expr::Call { callee, args: Box::new([x]), is_assignee_expr: false },
syntax_ptr.clone(),
);
- self.alloc_expr(Expr::Return { expr: Some(result) }, syntax_ptr.clone())
+ if let Some(label) = self.current_try_block {
+ let label = Some(self.body.labels[label].name.clone());
+ self.alloc_expr(Expr::Break { expr: Some(result), label }, syntax_ptr.clone())
+ } else {
+ self.alloc_expr(Expr::Return { expr: Some(result) }, syntax_ptr.clone())
+ }
},
};
let arms = Box::new([continue_arm, break_arm]);