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Auto merge of #14347 - HKalbasi:dev, r=lnicola

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Add storage dead for let bindings without initializer

fix #14344
This commit is contained in:
bors 2023-03-14 09:05:36 +00:00
commit 57803753b0
4 changed files with 79 additions and 44 deletions
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42
crates/hir-def/src/body.rs
View File

@ -24,7 +24,9 @@
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 @@ fn shrink_to_fit(&mut self) {
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 {

37
crates/hir-ty/src/infer/pat.rs
View File

@ -5,10 +5,7 @@
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),
}
}

20
crates/hir-ty/src/mir/lower.rs
View File

@ -1113,7 +1113,7 @@ fn pattern_match(
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 @@ fn is_uninhabited(&self, expr_id: ExprId) -> bool {
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 @@ fn push_storage_live(&mut self, b: BindingId, current: BasicBlockId) -> Result<(
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 @@ fn lower_block_to_place(
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 @@ fn lower_block_to_place(
}
}
}
} else {
self.body.walk_bindings_in_pat(*pat, |b| {
self.push_storage_live(b, current);
});
}
}
hir_def::expr::Statement::Expr { expr, has_semi: _ } => {

24
crates/ide-diagnostics/src/handlers/mutability_errors.rs
View File

@ -505,6 +505,30 @@ 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(