Diagnose incorrect continue expressions

This commit is contained in:
Lukas Wirth 2022-09-01 14:30:57 +02:00
parent d6fc4a9ea6
commit 1e66a5a8ce
5 changed files with 48 additions and 31 deletions

View file

@ -182,7 +182,7 @@ pub(crate) type InferResult<T> = Result<InferOk<T>, TypeError>;
#[derive(Debug, PartialEq, Eq, Clone)]
pub enum InferenceDiagnostic {
NoSuchField { expr: ExprId },
BreakOutsideOfLoop { expr: ExprId },
BreakOutsideOfLoop { expr: ExprId, is_break: bool },
MismatchedArgCount { call_expr: ExprId, expected: usize, found: usize },
}

View file

@ -120,19 +120,16 @@ impl<'a> InferenceContext<'a> {
let ty = match label {
Some(_) => {
let break_ty = self.table.new_type_var();
let (ctx, ty) = self.with_breakable_ctx(break_ty.clone(), *label, |this| {
this.infer_block(
tgt_expr,
statements,
*tail,
&Expectation::has_type(break_ty),
)
});
if ctx.may_break {
ctx.coerce.complete()
} else {
ty
}
let (breaks, ty) =
self.with_breakable_ctx(break_ty.clone(), *label, |this| {
this.infer_block(
tgt_expr,
statements,
*tail,
&Expectation::has_type(break_ty),
)
});
breaks.unwrap_or(ty)
}
None => self.infer_block(tgt_expr, statements, *tail, expected),
};
@ -164,15 +161,16 @@ impl<'a> InferenceContext<'a> {
}
&Expr::Loop { body, label } => {
let ty = self.table.new_type_var();
let (ctx, ()) = self.with_breakable_ctx(ty, label, |this| {
let (breaks, ()) = self.with_breakable_ctx(ty, label, |this| {
this.infer_expr(body, &Expectation::has_type(TyBuilder::unit()));
});
if ctx.may_break {
self.diverges = Diverges::Maybe;
ctx.coerce.complete()
} else {
TyKind::Never.intern(Interner)
match breaks {
Some(breaks) => {
self.diverges = Diverges::Maybe;
breaks
}
None => TyKind::Never.intern(Interner),
}
}
&Expr::While { condition, body, label } => {
@ -194,7 +192,7 @@ impl<'a> InferenceContext<'a> {
self.resolve_associated_type(iterable_ty, self.resolve_into_iter_item());
self.infer_pat(pat, &pat_ty, BindingMode::default());
let (_ctx, ()) = self.with_breakable_ctx(self.err_ty(), label, |this| {
self.with_breakable_ctx(self.err_ty(), label, |this| {
this.infer_expr(body, &Expectation::has_type(TyBuilder::unit()));
});
@ -356,7 +354,15 @@ impl<'a> InferenceContext<'a> {
let resolver = resolver_for_expr(self.db.upcast(), self.owner, tgt_expr);
self.infer_path(&resolver, p, tgt_expr.into()).unwrap_or_else(|| self.err_ty())
}
Expr::Continue { .. } => TyKind::Never.intern(Interner),
Expr::Continue { label } => {
if let None = find_breakable(&mut self.breakables, label.as_ref()) {
self.push_diagnostic(InferenceDiagnostic::BreakOutsideOfLoop {
expr: tgt_expr,
is_break: false,
});
};
TyKind::Never.intern(Interner)
}
Expr::Break { expr, label } => {
let mut coerce = match find_breakable(&mut self.breakables, label.as_ref()) {
Some(ctxt) => {
@ -384,6 +390,7 @@ impl<'a> InferenceContext<'a> {
} else {
self.push_diagnostic(InferenceDiagnostic::BreakOutsideOfLoop {
expr: tgt_expr,
is_break: true,
});
};
@ -1462,13 +1469,13 @@ impl<'a> InferenceContext<'a> {
ty: Ty,
label: Option<LabelId>,
cb: impl FnOnce(&mut Self) -> T,
) -> (BreakableContext, T) {
) -> (Option<Ty>, T) {
self.breakables.push({
let label = label.map(|label| self.body[label].name.clone());
BreakableContext { may_break: false, coerce: CoerceMany::new(ty), label }
});
let res = cb(self);
let ctx = self.breakables.pop().expect("breakable stack broken");
(ctx, res)
(ctx.may_break.then(|| ctx.coerce.complete()), res)
}
}

View file

@ -124,6 +124,7 @@ pub struct NoSuchField {
#[derive(Debug)]
pub struct BreakOutsideOfLoop {
pub expr: InFile<AstPtr<ast::Expr>>,
pub is_break: bool,
}
#[derive(Debug)]

View file

@ -1216,11 +1216,11 @@ impl DefWithBody {
let field = source_map.field_syntax(*expr);
acc.push(NoSuchField { field }.into())
}
hir_ty::InferenceDiagnostic::BreakOutsideOfLoop { expr } => {
&hir_ty::InferenceDiagnostic::BreakOutsideOfLoop { expr, is_break } => {
let expr = source_map
.expr_syntax(*expr)
.expr_syntax(expr)
.expect("break outside of loop in synthetic syntax");
acc.push(BreakOutsideOfLoop { expr }.into())
acc.push(BreakOutsideOfLoop { expr, is_break }.into())
}
hir_ty::InferenceDiagnostic::MismatchedArgCount { call_expr, expected, found } => {
match source_map.expr_syntax(*call_expr) {

View file

@ -7,9 +7,10 @@ pub(crate) fn break_outside_of_loop(
ctx: &DiagnosticsContext<'_>,
d: &hir::BreakOutsideOfLoop,
) -> Diagnostic {
let construct = if d.is_break { "break" } else { "continue" };
Diagnostic::new(
"break-outside-of-loop",
"break outside of loop",
format!("{construct} outside of loop"),
ctx.sema.diagnostics_display_range(d.expr.clone().map(|it| it.into())).range,
)
}
@ -19,11 +20,19 @@ mod tests {
use crate::tests::check_diagnostics;
#[test]
fn break_outside_of_loop() {
fn outside_of_loop() {
check_diagnostics(
r#"
fn foo() { break; }
//^^^^^ error: break outside of loop
fn foo() {
break;
//^^^^^ error: break outside of loop
break 'a;
//^^^^^^^^ error: break outside of loop
continue;
//^^^^^^^^ error: continue outside of loop
continue 'a;
//^^^^^^^^^^^ error: continue outside of loop
}
"#,
);
}