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typeck/expr.rs: move check_expr_assign here.

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This commit is contained in:
Mazdak Farrokhzad 2019-06-15 02:10:56 +02:00
parent 7a41cc1715
commit af800c7873
2 changed files with 46 additions and 46 deletions
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47
src/librustc_typeck/check/expr.rs
View file

@ -90,7 +90,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
self.check_expr_return(expr_opt.deref(), expr)
}
ExprKind::Assign(ref lhs, ref rhs) => {
self.check_assign(expr, expected, lhs, rhs)
self.check_expr_assign(expr, expected, lhs, rhs)
}
ExprKind::While(ref cond, ref body, _) => {
let ctxt = BreakableCtxt {
@ -742,4 +742,49 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
}
self.tcx.types.never
}
/// Type check assignment expression `expr` of form `lhs = rhs`.
/// The expected type is `()` and is passsed to the function for the purposes of diagnostics.
fn check_expr_assign(
&self,
expr: &'tcx hir::Expr,
expected: Expectation<'tcx>,
lhs: &'tcx hir::Expr,
rhs: &'tcx hir::Expr,
) -> Ty<'tcx> {
let lhs_ty = self.check_expr_with_needs(&lhs, Needs::MutPlace);
let rhs_ty = self.check_expr_coercable_to_type(&rhs, lhs_ty);
let expected_ty = expected.coercion_target_type(self, expr.span);
if expected_ty == self.tcx.types.bool {
// The expected type is `bool` but this will result in `()` so we can reasonably
// say that the user intended to write `lhs == rhs` instead of `lhs = rhs`.
// The likely cause of this is `if foo = bar { .. }`.
let actual_ty = self.tcx.mk_unit();
let mut err = self.demand_suptype_diag(expr.span, expected_ty, actual_ty).unwrap();
let msg = "try comparing for equality";
let left = self.tcx.sess.source_map().span_to_snippet(lhs.span);
let right = self.tcx.sess.source_map().span_to_snippet(rhs.span);
if let (Ok(left), Ok(right)) = (left, right) {
let help = format!("{} == {}", left, right);
err.span_suggestion(expr.span, msg, help, Applicability::MaybeIncorrect);
} else {
err.help(msg);
}
err.emit();
} else if !lhs.is_place_expr() {
struct_span_err!(self.tcx.sess, expr.span, E0070,
"invalid left-hand side expression")
.span_label(expr.span, "left-hand of expression not valid")
.emit();
}
self.require_type_is_sized(lhs_ty, lhs.span, traits::AssignmentLhsSized);
if lhs_ty.references_error() || rhs_ty.references_error() {
self.tcx.types.err
} else {
self.tcx.mk_unit()
}
}
}

45
src/librustc_typeck/check/mod.rs
View file

@ -3983,51 +3983,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
ty
}
/// Type check assignment expression `expr` of form `lhs = rhs`.
/// The expected type is `()` and is passsed to the function for the purposes of diagnostics.
fn check_assign(
&self,
expr: &'tcx hir::Expr,
expected: Expectation<'tcx>,
lhs: &'tcx hir::Expr,
rhs: &'tcx hir::Expr,
) -> Ty<'tcx> {
let lhs_ty = self.check_expr_with_needs(&lhs, Needs::MutPlace);
let rhs_ty = self.check_expr_coercable_to_type(&rhs, lhs_ty);
let expected_ty = expected.coercion_target_type(self, expr.span);
if expected_ty == self.tcx.types.bool {
// The expected type is `bool` but this will result in `()` so we can reasonably
// say that the user intended to write `lhs == rhs` instead of `lhs = rhs`.
// The likely cause of this is `if foo = bar { .. }`.
let actual_ty = self.tcx.mk_unit();
let mut err = self.demand_suptype_diag(expr.span, expected_ty, actual_ty).unwrap();
let msg = "try comparing for equality";
let left = self.tcx.sess.source_map().span_to_snippet(lhs.span);
let right = self.tcx.sess.source_map().span_to_snippet(rhs.span);
if let (Ok(left), Ok(right)) = (left, right) {
let help = format!("{} == {}", left, right);
err.span_suggestion(expr.span, msg, help, Applicability::MaybeIncorrect);
} else {
err.help(msg);
}
err.emit();
} else if !lhs.is_place_expr() {
struct_span_err!(self.tcx.sess, expr.span, E0070,
"invalid left-hand side expression")
.span_label(expr.span, "left-hand of expression not valid")
.emit();
}
self.require_type_is_sized(lhs_ty, lhs.span, traits::AssignmentLhsSized);
if lhs_ty.references_error() || rhs_ty.references_error() {
self.tcx.types.err
} else {
self.tcx.mk_unit()
}
}
// Finish resolving a path in a struct expression or pattern `S::A { .. }` if necessary.
// The newly resolved definition is written into `type_dependent_defs`.
fn finish_resolving_struct_path(&self,