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Diagnose value breaks in incorrect breakables

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This commit is contained in:
Lukas Wirth 2023-03-03 17:28:57 +01:00
parent 02eb2d758e
commit 41f234df09
5 changed files with 70 additions and 37 deletions
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5
crates/hir-ty/src/infer.rs
View file

@ -167,7 +167,8 @@ pub enum InferenceDiagnostic {
NoSuchField { expr: ExprId },
PrivateField { expr: ExprId, field: FieldId },
PrivateAssocItem { id: ExprOrPatId, item: AssocItemId },
BreakOutsideOfLoop { expr: ExprId, is_break: bool },
// FIXME: Make this proper
BreakOutsideOfLoop { expr: ExprId, is_break: bool, bad_value_break: bool },
MismatchedArgCount { call_expr: ExprId, expected: usize, found: usize },
}
@ -411,7 +412,7 @@ struct BreakableContext {
/// Whether this context contains at least one break expression.
may_break: bool,
/// The coercion target of the context.
coerce: CoerceMany,
coerce: Option<CoerceMany>,
/// The optional label of the context.
label: Option<name::Name>,
kind: BreakableKind,

60
crates/hir-ty/src/infer/expr.rs
View file

@ -133,7 +133,7 @@ impl<'a> InferenceContext<'a> {
let break_ty = self.table.new_type_var();
let (breaks, ty) = self.with_breakable_ctx(
BreakableKind::Block,
break_ty.clone(),
Some(break_ty.clone()),
*label,
|this| {
this.infer_block(
@ -153,7 +153,7 @@ impl<'a> InferenceContext<'a> {
}
Expr::Unsafe { body } => self.infer_expr(*body, expected),
Expr::Const { body } => {
self.with_breakable_ctx(BreakableKind::Border, self.err_ty(), None, |this| {
self.with_breakable_ctx(BreakableKind::Border, None, None, |this| {
this.infer_expr(*body, expected)
})
.1
@ -169,7 +169,7 @@ impl<'a> InferenceContext<'a> {
let ok_ty =
self.resolve_associated_type(try_ty.clone(), self.resolve_ops_try_output());
self.with_breakable_ctx(BreakableKind::Block, ok_ty.clone(), None, |this| {
self.with_breakable_ctx(BreakableKind::Block, Some(ok_ty.clone()), None, |this| {
this.infer_expr(*body, &Expectation::has_type(ok_ty));
});
@ -183,7 +183,7 @@ impl<'a> InferenceContext<'a> {
mem::replace(&mut self.return_coercion, Some(CoerceMany::new(ret_ty.clone())));
let (_, inner_ty) =
self.with_breakable_ctx(BreakableKind::Border, self.err_ty(), None, |this| {
self.with_breakable_ctx(BreakableKind::Border, None, None, |this| {
this.infer_expr_coerce(*body, &Expectation::has_type(ret_ty))
});
@ -203,7 +203,7 @@ impl<'a> InferenceContext<'a> {
// let ty = expected.coercion_target_type(&mut self.table);
let ty = self.table.new_type_var();
let (breaks, ()) =
self.with_breakable_ctx(BreakableKind::Loop, ty, label, |this| {
self.with_breakable_ctx(BreakableKind::Loop, Some(ty), label, |this| {
this.infer_expr(body, &Expectation::HasType(TyBuilder::unit()));
});
@ -216,7 +216,7 @@ impl<'a> InferenceContext<'a> {
}
}
&Expr::While { condition, body, label } => {
self.with_breakable_ctx(BreakableKind::Loop, self.err_ty(), label, |this| {
self.with_breakable_ctx(BreakableKind::Loop, None, label, |this| {
this.infer_expr(
condition,
&Expectation::HasType(this.result.standard_types.bool_.clone()),
@ -236,7 +236,7 @@ impl<'a> InferenceContext<'a> {
self.resolve_associated_type(into_iter_ty, self.resolve_iterator_item());
self.infer_top_pat(pat, &pat_ty);
self.with_breakable_ctx(BreakableKind::Loop, self.err_ty(), label, |this| {
self.with_breakable_ctx(BreakableKind::Loop, None, label, |this| {
this.infer_expr(body, &Expectation::HasType(TyBuilder::unit()));
});
@ -321,7 +321,7 @@ impl<'a> InferenceContext<'a> {
let prev_resume_yield_tys =
mem::replace(&mut self.resume_yield_tys, resume_yield_tys);
self.with_breakable_ctx(BreakableKind::Border, self.err_ty(), None, |this| {
self.with_breakable_ctx(BreakableKind::Border, None, None, |this| {
this.infer_return(*body);
});
@ -439,42 +439,50 @@ impl<'a> InferenceContext<'a> {
self.push_diagnostic(InferenceDiagnostic::BreakOutsideOfLoop {
expr: tgt_expr,
is_break: false,
bad_value_break: false,
});
};
self.result.standard_types.never.clone()
}
Expr::Break { expr, label } => {
let val_ty = if let Some(expr) = *expr {
let opt_coerce_to = find_breakable(&mut self.breakables, label.as_ref())
.map(|ctxt| ctxt.coerce.expected_ty());
self.infer_expr_inner(
expr,
&Expectation::HasType(opt_coerce_to.unwrap_or_else(|| self.err_ty())),
)
let opt_coerce_to = match find_breakable(&mut self.breakables, label.as_ref()) {
Some(ctxt) => match &ctxt.coerce {
Some(coerce) => coerce.expected_ty(),
None => {
self.push_diagnostic(InferenceDiagnostic::BreakOutsideOfLoop {
expr: tgt_expr,
is_break: true,
bad_value_break: true,
});
self.err_ty()
}
},
None => self.err_ty(),
};
self.infer_expr_inner(expr, &Expectation::HasType(opt_coerce_to))
} else {
TyBuilder::unit()
};
match find_breakable(&mut self.breakables, label.as_ref()) {
Some(ctxt) => {
// avoiding the borrowck
let mut coerce = mem::replace(
&mut ctxt.coerce,
CoerceMany::new(expected.coercion_target_type(&mut self.table)),
);
// FIXME: create a synthetic `()` during lowering so we have something to refer to here?
Some(ctxt) => match ctxt.coerce.take() {
Some(mut coerce) => {
coerce.coerce(self, *expr, &val_ty);
// Avoiding borrowck
let ctxt = find_breakable(&mut self.breakables, label.as_ref())
.expect("breakable stack changed during coercion");
ctxt.coerce = coerce;
ctxt.may_break = true;
ctxt.coerce = Some(coerce);
}
None => ctxt.may_break = true,
},
None => {
self.push_diagnostic(InferenceDiagnostic::BreakOutsideOfLoop {
expr: tgt_expr,
is_break: true,
bad_value_break: false,
});
}
}
@ -1712,16 +1720,16 @@ impl<'a> InferenceContext<'a> {
fn with_breakable_ctx<T>(
&mut self,
kind: BreakableKind,
ty: Ty,
ty: Option<Ty>,
label: Option<LabelId>,
cb: impl FnOnce(&mut Self) -> T,
) -> (Option<Ty>, T) {
self.breakables.push({
let label = label.map(|label| self.body[label].name.clone());
BreakableContext { kind, may_break: false, coerce: CoerceMany::new(ty), label }
BreakableContext { kind, may_break: false, coerce: ty.map(CoerceMany::new), label }
});
let res = cb(self);
let ctx = self.breakables.pop().expect("breakable stack broken");
(ctx.may_break.then(|| ctx.coerce.complete(self)), res)
(if ctx.may_break { ctx.coerce.map(|ctx| ctx.complete(self)) } else { None }, res)
}
}

1
crates/hir/src/diagnostics.rs
View file

@ -140,6 +140,7 @@ pub struct PrivateField {
pub struct BreakOutsideOfLoop {
pub expr: InFile<AstPtr<ast::Expr>>,
pub is_break: bool,
pub bad_value_break: bool,
}
#[derive(Debug)]

8
crates/hir/src/lib.rs
View file

@ -1373,11 +1373,15 @@ impl DefWithBody {
let field = source_map.field_syntax(*expr);
acc.push(NoSuchField { field }.into())
}
&hir_ty::InferenceDiagnostic::BreakOutsideOfLoop { expr, is_break } => {
&hir_ty::InferenceDiagnostic::BreakOutsideOfLoop {
expr,
is_break,
bad_value_break,
} => {
let expr = source_map
.expr_syntax(expr)
.expect("break outside of loop in synthetic syntax");
acc.push(BreakOutsideOfLoop { expr, is_break }.into())
acc.push(BreakOutsideOfLoop { expr, is_break, bad_value_break }.into())
}
hir_ty::InferenceDiagnostic::MismatchedArgCount { call_expr, expected, found } => {
match source_map.expr_syntax(*call_expr) {

21
crates/ide-diagnostics/src/handlers/break_outside_of_loop.rs
View file

@ -7,10 +7,15 @@ pub(crate) fn break_outside_of_loop(
ctx: &DiagnosticsContext<'_>,
d: &hir::BreakOutsideOfLoop,
) -> Diagnostic {
let message = if d.bad_value_break {
"can't break with a value in this position".to_owned()
} else {
let construct = if d.is_break { "break" } else { "continue" };
format!("{construct} outside of loop")
};
Diagnostic::new(
"break-outside-of-loop",
format!("{construct} outside of loop"),
message,
ctx.sema.diagnostics_display_range(d.expr.clone().map(|it| it.into())).range,
)
}
@ -132,6 +137,20 @@ fn foo() {
//^^^^^^^^^^^ error: continue outside of loop
}
}
"#,
);
}
#[test]
fn value_break_in_for_loop() {
check_diagnostics(
r#"
fn test() {
for _ in [()] {
break 3;
// ^^^^^^^ error: can't break with a value in this position
}
}
"#,
);
}