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Add storage dead for let bindings without initializer
| -rw-r--r-- | crates/hir-def/src/body.rs | 42 | ||||
| -rw-r--r-- | crates/hir-ty/src/infer/pat.rs | 37 | ||||
| -rw-r--r-- | crates/hir-ty/src/mir/lower.rs | 20 | ||||
| -rw-r--r-- | crates/ide-diagnostics/src/handlers/mutability_errors.rs | 24 |
4 files changed, 79 insertions, 44 deletions
diff --git a/crates/hir-def/src/body.rs b/crates/hir-def/src/body.rs index 3be477d487..b70e658efd 100644 --- a/crates/hir-def/src/body.rs +++ b/crates/hir-def/src/body.rs @@ -24,7 +24,9 @@ use syntax::{ast, AstPtr, SyntaxNode, SyntaxNodePtr}; use crate::{ attr::Attrs, db::DefDatabase, - expr::{dummy_expr_id, Binding, BindingId, Expr, ExprId, Label, LabelId, Pat, PatId}, + expr::{ + dummy_expr_id, Binding, BindingId, Expr, ExprId, Label, LabelId, Pat, PatId, RecordFieldPat, + }, item_scope::BuiltinShadowMode, macro_id_to_def_id, nameres::DefMap, @@ -432,6 +434,44 @@ impl Body { pats.shrink_to_fit(); bindings.shrink_to_fit(); } + + pub fn walk_bindings_in_pat(&self, pat_id: PatId, mut f: impl FnMut(BindingId)) { + self.walk_pats(pat_id, &mut |pat| { + if let Pat::Bind { id, .. } = pat { + f(*id); + } + }); + } + + pub fn walk_pats(&self, pat_id: PatId, f: &mut impl FnMut(&Pat)) { + let pat = &self[pat_id]; + f(pat); + match pat { + Pat::Range { .. } + | Pat::Lit(..) + | Pat::Path(..) + | Pat::ConstBlock(..) + | Pat::Wild + | Pat::Missing => {} + &Pat::Bind { subpat, .. } => { + if let Some(subpat) = subpat { + self.walk_pats(subpat, f); + } + } + Pat::Or(args) | Pat::Tuple { args, .. } | Pat::TupleStruct { args, .. } => { + args.iter().copied().for_each(|p| self.walk_pats(p, f)); + } + Pat::Ref { pat, .. } => self.walk_pats(*pat, f), + Pat::Slice { prefix, slice, suffix } => { + let total_iter = prefix.iter().chain(slice.iter()).chain(suffix.iter()); + total_iter.copied().for_each(|p| self.walk_pats(p, f)); + } + Pat::Record { args, .. } => { + args.iter().for_each(|RecordFieldPat { pat, .. }| self.walk_pats(*pat, f)); + } + Pat::Box { inner } => self.walk_pats(*inner, f), + } + } } impl Default for Body { diff --git a/crates/hir-ty/src/infer/pat.rs b/crates/hir-ty/src/infer/pat.rs index 0f49e83788..5f839fc307 100644 --- a/crates/hir-ty/src/infer/pat.rs +++ b/crates/hir-ty/src/infer/pat.rs @@ -5,10 +5,7 @@ use std::iter::repeat_with; use chalk_ir::Mutability; use hir_def::{ body::Body, - expr::{ - Binding, BindingAnnotation, BindingId, Expr, ExprId, ExprOrPatId, Literal, Pat, PatId, - RecordFieldPat, - }, + expr::{Binding, BindingAnnotation, BindingId, Expr, ExprId, ExprOrPatId, Literal, Pat, PatId}, path::Path, }; use hir_expand::name::Name; @@ -439,38 +436,8 @@ fn is_non_ref_pat(body: &hir_def::body::Body, pat: PatId) -> bool { pub(super) fn contains_explicit_ref_binding(body: &Body, pat_id: PatId) -> bool { let mut res = false; - walk_pats(body, pat_id, &mut |pat| { + body.walk_pats(pat_id, &mut |pat| { res |= matches!(pat, Pat::Bind { id, .. } if body.bindings[*id].mode == BindingAnnotation::Ref); }); res } - -fn walk_pats(body: &Body, pat_id: PatId, f: &mut impl FnMut(&Pat)) { - let pat = &body[pat_id]; - f(pat); - match pat { - Pat::Range { .. } - | Pat::Lit(..) - | Pat::Path(..) - | Pat::ConstBlock(..) - | Pat::Wild - | Pat::Missing => {} - &Pat::Bind { subpat, .. } => { - if let Some(subpat) = subpat { - walk_pats(body, subpat, f); - } - } - Pat::Or(args) | Pat::Tuple { args, .. } | Pat::TupleStruct { args, .. } => { - args.iter().copied().for_each(|p| walk_pats(body, p, f)); - } - Pat::Ref { pat, .. } => walk_pats(body, *pat, f), - Pat::Slice { prefix, slice, suffix } => { - let total_iter = prefix.iter().chain(slice.iter()).chain(suffix.iter()); - total_iter.copied().for_each(|p| walk_pats(body, p, f)); - } - Pat::Record { args, .. } => { - args.iter().for_each(|RecordFieldPat { pat, .. }| walk_pats(body, *pat, f)); - } - Pat::Box { inner } => walk_pats(body, *inner, f), - } -} diff --git a/crates/hir-ty/src/mir/lower.rs b/crates/hir-ty/src/mir/lower.rs index 435a914088..c4dd7c0ace 100644 --- a/crates/hir-ty/src/mir/lower.rs +++ b/crates/hir-ty/src/mir/lower.rs @@ -1113,7 +1113,7 @@ impl MirLowerCtx<'_> { if matches!(mode, BindingAnnotation::Ref | BindingAnnotation::RefMut) { binding_mode = mode; } - self.push_storage_live(*id, current)?; + self.push_storage_live(*id, current); self.push_assignment( current, target_place.into(), @@ -1327,8 +1327,9 @@ impl MirLowerCtx<'_> { is_ty_uninhabited_from(&self.infer[expr_id], self.owner.module(self.db.upcast()), self.db) } - /// This function push `StorageLive` statements for each binding in the pattern. - fn push_storage_live(&mut self, b: BindingId, current: BasicBlockId) -> Result<()> { + /// This function push `StorageLive` statement for the binding, and applies changes to add `StorageDead` in + /// the appropriated places. + fn push_storage_live(&mut self, b: BindingId, current: BasicBlockId) { // Current implementation is wrong. It adds no `StorageDead` at the end of scope, and before each break // and continue. It just add a `StorageDead` before the `StorageLive`, which is not wrong, but unneeeded in // the proper implementation. Due this limitation, implementing a borrow checker on top of this mir will falsely @@ -1356,7 +1357,6 @@ impl MirLowerCtx<'_> { let l = self.result.binding_locals[b]; self.push_statement(current, StatementKind::StorageDead(l).with_span(span)); self.push_statement(current, StatementKind::StorageLive(l).with_span(span)); - Ok(()) } fn resolve_lang_item(&self, item: LangItem) -> Result<LangItemTarget> { @@ -1381,10 +1381,10 @@ impl MirLowerCtx<'_> { if let Some(expr_id) = initializer { let else_block; let Some((init_place, c)) = - self.lower_expr_as_place(current, *expr_id, true)? - else { - return Ok(None); - }; + self.lower_expr_as_place(current, *expr_id, true)? + else { + return Ok(None); + }; current = c; (current, else_block) = self.pattern_match( current, @@ -1407,6 +1407,10 @@ impl MirLowerCtx<'_> { } } } + } else { + self.body.walk_bindings_in_pat(*pat, |b| { + self.push_storage_live(b, current); + }); } } hir_def::expr::Statement::Expr { expr, has_semi: _ } => { diff --git a/crates/ide-diagnostics/src/handlers/mutability_errors.rs b/crates/ide-diagnostics/src/handlers/mutability_errors.rs index 84189a5d56..96470265d1 100644 --- a/crates/ide-diagnostics/src/handlers/mutability_errors.rs +++ b/crates/ide-diagnostics/src/handlers/mutability_errors.rs @@ -506,6 +506,30 @@ fn main() { } #[test] + fn initialization_is_not_mutation_in_loop() { + check_diagnostics( + r#" +fn main() { + let a; + loop { + let c @ ( + mut b, + //^^^^^ 💡 weak: variable does not need to be mutable + mut d + //^^^^^ 💡 weak: variable does not need to be mutable + ); + a = 1; + //^^^^^ 💡 error: cannot mutate immutable variable `a` + b = 1; + c = (2, 3); + d = 3; + } +} +"#, + ); + } + + #[test] fn function_arguments_are_initialized() { check_diagnostics( r#" |