tcx.mk_unit()
}
ExprKind::Break(destination, ref expr_opt) => {
- if let Ok(target_id) = destination.target_id {
- let (e_ty, cause);
- if let Some(ref e) = *expr_opt {
- // If this is a break with a value, we need to type-check
- // the expression. Get an expected type from the loop context.
- let opt_coerce_to = {
- let mut enclosing_breakables = self.enclosing_breakables.borrow_mut();
- enclosing_breakables.find_breakable(target_id)
- .coerce
- .as_ref()
- .map(|coerce| coerce.expected_ty())
- };
-
- // If the loop context is not a `loop { }`, then break with
- // a value is illegal, and `opt_coerce_to` will be `None`.
- // Just set expectation to error in that case.
- let coerce_to = opt_coerce_to.unwrap_or(tcx.types.err);
-
- // Recurse without `enclosing_breakables` borrowed.
- e_ty = self.check_expr_with_hint(e, coerce_to);
- cause = self.misc(e.span);
- } else {
- // Otherwise, this is a break *without* a value. That's
- // always legal, and is equivalent to `break ()`.
- e_ty = tcx.mk_unit();
- cause = self.misc(expr.span);
- }
-
- // Now that we have type-checked `expr_opt`, borrow
- // the `enclosing_loops` field and let's coerce the
- // type of `expr_opt` into what is expected.
- let mut enclosing_breakables = self.enclosing_breakables.borrow_mut();
- let ctxt = enclosing_breakables.find_breakable(target_id);
- if let Some(ref mut coerce) = ctxt.coerce {
- if let Some(ref e) = *expr_opt {
- coerce.coerce(self, &cause, e, e_ty);
- } else {
- assert!(e_ty.is_unit());
- coerce.coerce_forced_unit(self, &cause, &mut |_| (), true);
- }
- } else {
- // If `ctxt.coerce` is `None`, we can just ignore
- // the type of the expresison. This is because
- // either this was a break *without* a value, in
- // which case it is always a legal type (`()`), or
- // else an error would have been flagged by the
- // `loops` pass for using break with an expression
- // where you are not supposed to.
- assert!(expr_opt.is_none() || self.tcx.sess.err_count() > 0);
- }
-
- ctxt.may_break = true;
-
- // the type of a `break` is always `!`, since it diverges
- tcx.types.never
- } else {
- // Otherwise, we failed to find the enclosing loop;
- // this can only happen if the `break` was not
- // inside a loop at all, which is caught by the
- // loop-checking pass.
- if self.tcx.sess.err_count() == 0 {
- self.tcx.sess.delay_span_bug(expr.span,
- "break was outside loop, but no error was emitted");
- }
-
- // We still need to assign a type to the inner expression to
- // prevent the ICE in #43162.
- if let Some(ref e) = *expr_opt {
- self.check_expr_with_hint(e, tcx.types.err);
-
- // ... except when we try to 'break rust;'.
- // ICE this expression in particular (see #43162).
- if let ExprKind::Path(QPath::Resolved(_, ref path)) = e.node {
- if path.segments.len() == 1 &&
- path.segments[0].ident.name == sym::rust {
- fatally_break_rust(self.tcx.sess);
- }
- }
- }
- // There was an error; make type-check fail.
- tcx.types.err
- }
-
+ self.check_expr_break(destination, expr_opt.deref(), expr)
}
ExprKind::Continue(destination) => {
if destination.target_id.is_ok() {
ty
}
+
+ fn check_expr_break(
+ &self,
+ destination: hir::Destination,
+ expr_opt: Option<&'tcx hir::Expr>,
+ expr: &'tcx hir::Expr,
+ ) -> Ty<'tcx> {
+ let tcx = self.tcx;
+ if let Ok(target_id) = destination.target_id {
+ let (e_ty, cause);
+ if let Some(ref e) = expr_opt {
+ // If this is a break with a value, we need to type-check
+ // the expression. Get an expected type from the loop context.
+ let opt_coerce_to = {
+ let mut enclosing_breakables = self.enclosing_breakables.borrow_mut();
+ enclosing_breakables.find_breakable(target_id)
+ .coerce
+ .as_ref()
+ .map(|coerce| coerce.expected_ty())
+ };
+
+ // If the loop context is not a `loop { }`, then break with
+ // a value is illegal, and `opt_coerce_to` will be `None`.
+ // Just set expectation to error in that case.
+ let coerce_to = opt_coerce_to.unwrap_or(tcx.types.err);
+
+ // Recurse without `enclosing_breakables` borrowed.
+ e_ty = self.check_expr_with_hint(e, coerce_to);
+ cause = self.misc(e.span);
+ } else {
+ // Otherwise, this is a break *without* a value. That's
+ // always legal, and is equivalent to `break ()`.
+ e_ty = tcx.mk_unit();
+ cause = self.misc(expr.span);
+ }
+
+ // Now that we have type-checked `expr_opt`, borrow
+ // the `enclosing_loops` field and let's coerce the
+ // type of `expr_opt` into what is expected.
+ let mut enclosing_breakables = self.enclosing_breakables.borrow_mut();
+ let ctxt = enclosing_breakables.find_breakable(target_id);
+ if let Some(ref mut coerce) = ctxt.coerce {
+ if let Some(ref e) = expr_opt {
+ coerce.coerce(self, &cause, e, e_ty);
+ } else {
+ assert!(e_ty.is_unit());
+ coerce.coerce_forced_unit(self, &cause, &mut |_| (), true);
+ }
+ } else {
+ // If `ctxt.coerce` is `None`, we can just ignore
+ // the type of the expresison. This is because
+ // either this was a break *without* a value, in
+ // which case it is always a legal type (`()`), or
+ // else an error would have been flagged by the
+ // `loops` pass for using break with an expression
+ // where you are not supposed to.
+ assert!(expr_opt.is_none() || self.tcx.sess.err_count() > 0);
+ }
+
+ ctxt.may_break = true;
+
+ // the type of a `break` is always `!`, since it diverges
+ tcx.types.never
+ } else {
+ // Otherwise, we failed to find the enclosing loop;
+ // this can only happen if the `break` was not
+ // inside a loop at all, which is caught by the
+ // loop-checking pass.
+ if self.tcx.sess.err_count() == 0 {
+ self.tcx.sess.delay_span_bug(expr.span,
+ "break was outside loop, but no error was emitted");
+ }
+
+ // We still need to assign a type to the inner expression to
+ // prevent the ICE in #43162.
+ if let Some(ref e) = expr_opt {
+ self.check_expr_with_hint(e, tcx.types.err);
+
+ // ... except when we try to 'break rust;'.
+ // ICE this expression in particular (see #43162).
+ if let ExprKind::Path(QPath::Resolved(_, ref path)) = e.node {
+ if path.segments.len() == 1 &&
+ path.segments[0].ident.name == sym::rust {
+ fatally_break_rust(self.tcx.sess);
+ }
+ }
+ }
+ // There was an error; make type-check fail.
+ tcx.types.err
+ }
+ }
}
projects / rust.git / commitdiff