use find_ancestor_inside to get right span in CastCheck
This commit is contained in:
Michael Goulet
parent
18f32b73bd
commit
d2b1bb8a9b
3 changed files with 42 additions and 18 deletions
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@ -55,6 +55,7 @@ use rustc_trait_selection::traits::error_reporting::report_object_safety_error;
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pub struct CastCheck<'tcx> {
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expr: &'tcx hir::Expr<'tcx>,
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expr_ty: Ty<'tcx>,
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expr_span: Span,
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cast_ty: Ty<'tcx>,
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cast_span: Span,
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span: Span,
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@ -207,7 +208,8 @@ impl<'a, 'tcx> CastCheck<'tcx> {
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cast_span: Span,
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span: Span,
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) -> Result<CastCheck<'tcx>, ErrorGuaranteed> {
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let check = CastCheck { expr, expr_ty, cast_ty, cast_span, span };
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let expr_span = expr.span.find_ancestor_inside(span).unwrap_or(expr.span);
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let check = CastCheck { expr, expr_ty, expr_span, cast_ty, cast_span, span };
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// For better error messages, check for some obviously unsized
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// cases now. We do a more thorough check at the end, once
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@ -240,15 +242,15 @@ impl<'a, 'tcx> CastCheck<'tcx> {
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error_span,
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format!("cannot cast `{}` as `{}`", fcx.ty_to_string(self.expr_ty), cast_ty),
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);
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if let Ok(snippet) = fcx.sess().source_map().span_to_snippet(self.expr.span) {
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if let Ok(snippet) = fcx.sess().source_map().span_to_snippet(self.expr_span) {
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err.span_suggestion(
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self.expr.span,
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self.expr_span,
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"dereference the expression",
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format!("*{}", snippet),
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Applicability::MaybeIncorrect,
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);
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} else {
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err.span_help(self.expr.span, "dereference the expression with `*`");
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err.span_help(self.expr_span, "dereference the expression with `*`");
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}
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err.emit();
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}
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@ -315,7 +317,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
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struct_span_err!(fcx.tcx.sess, self.span, E0054, "cannot cast as `bool`");
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if self.expr_ty.is_numeric() {
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match fcx.tcx.sess.source_map().span_to_snippet(self.expr.span) {
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match fcx.tcx.sess.source_map().span_to_snippet(self.expr_span) {
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Ok(snippet) => {
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err.span_suggestion(
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self.span,
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@ -440,7 +442,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
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}
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if sugg_mutref {
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err.span_label(self.span, "invalid cast");
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err.span_note(self.expr.span, "this reference is immutable");
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err.span_note(self.expr_span, "this reference is immutable");
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err.span_note(self.cast_span, "trying to cast to a mutable reference type");
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} else if let Some((sugg, remove_cast)) = sugg {
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err.span_label(self.span, "invalid cast");
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@ -449,7 +451,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
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.tcx
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.sess
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.source_map()
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.span_to_snippet(self.expr.span)
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.span_to_snippet(self.expr_span)
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.map_or(false, |snip| snip.starts_with('('));
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// Very crude check to see whether the expression must be wrapped
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@ -458,14 +460,14 @@ impl<'a, 'tcx> CastCheck<'tcx> {
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let needs_parens =
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!has_parens && matches!(self.expr.kind, hir::ExprKind::Cast(..));
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let mut suggestion = vec![(self.expr.span.shrink_to_lo(), sugg)];
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let mut suggestion = vec![(self.expr_span.shrink_to_lo(), sugg)];
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if needs_parens {
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suggestion[0].1 += "(";
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suggestion.push((self.expr.span.shrink_to_hi(), ")".to_string()));
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suggestion.push((self.expr_span.shrink_to_hi(), ")".to_string()));
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}
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if remove_cast {
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suggestion.push((
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self.expr.span.shrink_to_hi().to(self.cast_span),
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self.expr_span.shrink_to_hi().to(self.cast_span),
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String::new(),
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));
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}
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@ -481,7 +483,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
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) {
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let mut label = true;
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// Check `impl From<self.expr_ty> for self.cast_ty {}` for accurate suggestion:
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if let Ok(snippet) = fcx.tcx.sess.source_map().span_to_snippet(self.expr.span) {
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if let Ok(snippet) = fcx.tcx.sess.source_map().span_to_snippet(self.expr_span) {
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if let Some(from_trait) = fcx.tcx.get_diagnostic_item(sym::From) {
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let ty = fcx.resolve_vars_if_possible(self.cast_ty);
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// Erase regions to avoid panic in `prove_value` when calling
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@ -550,7 +552,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
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if fcx.tcx.sess.is_nightly_build() {
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err.span_label(
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self.expr.span,
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self.expr_span,
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"consider casting this expression to `*const ()`, \
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then using `core::ptr::from_raw_parts`",
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);
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@ -651,7 +653,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
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}
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}
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_ => {
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err.span_help(self.expr.span, "consider using a box or reference as appropriate");
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err.span_help(self.expr_span, "consider using a box or reference as appropriate");
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}
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}
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err.emit()
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@ -685,7 +687,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
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#[instrument(skip(fcx), level = "debug")]
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pub fn check(mut self, fcx: &FnCtxt<'a, 'tcx>) {
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self.expr_ty = fcx.structurally_resolved_type(self.expr.span, self.expr_ty);
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self.expr_ty = fcx.structurally_resolved_type(self.expr_span, self.expr_ty);
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self.cast_ty = fcx.structurally_resolved_type(self.cast_span, self.cast_ty);
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debug!("check_cast({}, {:?} as {:?})", self.expr.hir_id, self.expr_ty, self.cast_ty);
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@ -741,7 +743,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
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ty::FnDef(..) => {
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// Attempt a coercion to a fn pointer type.
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let f = fcx.normalize_associated_types_in(
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self.expr.span,
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self.expr_span,
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self.expr_ty.fn_sig(fcx.tcx),
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);
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let res = fcx.try_coerce(
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@ -997,7 +999,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
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));
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let msg = "use `.addr()` to obtain the address of a pointer";
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if let Ok(snippet) = fcx.tcx.sess.source_map().span_to_snippet(self.expr.span) {
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if let Ok(snippet) = fcx.tcx.sess.source_map().span_to_snippet(self.expr_span) {
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let scalar_cast = match t_c {
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ty::cast::IntTy::U(ty::UintTy::Usize) => String::new(),
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_ => format!(" as {}", self.cast_ty),
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@ -1027,13 +1029,12 @@ impl<'a, 'tcx> CastCheck<'tcx> {
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self.expr.hir_id,
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self.span,
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|err| {
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let mut err = err.build(&format!(
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"strict provenance disallows casting integer `{}` to pointer `{}`",
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self.expr_ty, self.cast_ty
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));
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let msg = "use `.with_addr()` to adjust a valid pointer in the same allocation, to this address";
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if let Ok(snippet) = fcx.tcx.sess.source_map().span_to_snippet(self.expr.span) {
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if let Ok(snippet) = fcx.tcx.sess.source_map().span_to_snippet(self.expr_span) {
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err.span_suggestion(
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self.span,
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msg,
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12
src/test/ui/cast/cast-macro-lhs.rs
Normal file
12
src/test/ui/cast/cast-macro-lhs.rs
Normal file
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@ -0,0 +1,12 @@
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// Test to make sure we suggest "consider casting" on the right span
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macro_rules! foo {
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() => { 0 }
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}
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fn main() {
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let x = foo!() as *const [u8];
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//~^ ERROR cannot cast `usize` to a pointer that is wide
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//~| NOTE creating a `*const [u8]` requires both an address and a length
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//~| NOTE consider casting this expression to `*const ()`, then using `core::ptr::from_raw_parts`
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}
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11
src/test/ui/cast/cast-macro-lhs.stderr
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11
src/test/ui/cast/cast-macro-lhs.stderr
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@ -0,0 +1,11 @@
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error[E0606]: cannot cast `usize` to a pointer that is wide
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--> $DIR/cast-macro-lhs.rs:8:23
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LL | let x = foo!() as *const [u8];
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| ------ ^^^^^^^^^^^ creating a `*const [u8]` requires both an address and a length
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| |
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| consider casting this expression to `*const ()`, then using `core::ptr::from_raw_parts`
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error: aborting due to previous error
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For more information about this error, try `rustc --explain E0606`.
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