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code review fixes

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This commit is contained in:
Saleem Jaffer 2019-04-17 17:58:33 +05:30
parent d0c0815f01
commit 999ee0190f
1 changed files with 24 additions and 25 deletions
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49
src/librustc_mir/hair/cx/expr.rs
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@ -68,6 +68,26 @@ impl<'tcx> Mirror<'tcx> for &'tcx hir::Expr {
}
}
/// Adjust the span from the block, to the last expression of the
/// block. This is a better span when returning a mutable reference
/// with too short a lifetime. The error message will use the span
/// from the assignment to the return place, which should only point
/// at the returned value, not the entire function body.
///
/// fn return_short_lived<'a>(x: &'a mut i32) -> &'static mut i32 {
/// x
/// // ^ error message points at this expression.
/// }
fn adjust_span<'tcx>(expr: &mut Expr<'tcx>) -> Span {
if let ExprKind::Block { body } = expr.kind {
if let Some(ref last_expr) = body.expr {
expr.span = last_expr.span;
}
}
expr.span
}
fn apply_adjustment<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
hir_expr: &'tcx hir::Expr,
mut expr: Expr<'tcx>,
@ -76,12 +96,7 @@ fn apply_adjustment<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
let Expr { temp_lifetime, mut span, .. } = expr;
let kind = match adjustment.kind {
Adjust::Pointer(PointerCast::Unsize) => {
if let ExprKind::Block { body } = expr.kind {
if let Some(ref last_expr) = body.expr {
span = last_expr.span;
expr.span = span;
}
}
span = adjust_span(&mut expr);
ExprKind::Pointer { cast: PointerCast::Unsize, source: expr.to_ref() }
}
Adjust::Pointer(cast) => {
@ -91,28 +106,12 @@ fn apply_adjustment<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
ExprKind::NeverToAny { source: expr.to_ref() }
}
Adjust::Deref(None) => {
// Adjust the span from the block, to the last expression of the
// block. This is a better span when returning a mutable reference
// with too short a lifetime. The error message will use the span
// from the assignment to the return place, which should only point
// at the returned value, not the entire function body.
//
// fn return_short_lived<'a>(x: &'a mut i32) -> &'static mut i32 {
// x
// // ^ error message points at this expression.
// }
//
// We don't need to do this adjustment in the next match arm since
// deref coercions always start with a built-in deref.
if let ExprKind::Block { body } = expr.kind {
if let Some(ref last_expr) = body.expr {
span = last_expr.span;
expr.span = span;
}
}
span = adjust_span(&mut expr);
ExprKind::Deref { arg: expr.to_ref() }
}
Adjust::Deref(Some(deref)) => {
// We don't need to do call adjust_span here since
// deref coercions always start with a built-in deref.
let call = deref.method_call(cx.tcx(), expr.ty);
expr = Expr {