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On recursive ADT, provide indirection structured suggestion
1 parent bb86748 commit c29b3fa

27 files changed

+315
-66
lines changed

‎src/librustc_errors/diagnostic.rs‎

Lines changed: 23 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -296,6 +296,29 @@ impl Diagnostic {
296296
self
297297
}
298298

299+
pub fn multipart_suggestions(
300+
&mut self,
301+
msg: &str,
302+
suggestions: Vec<Vec<(Span, String)>>,
303+
applicability: Applicability,
304+
) -> &mut Self {
305+
self.suggestions.push(CodeSuggestion {
306+
substitutions: suggestions
307+
.into_iter()
308+
.map(|suggestion| Substitution {
309+
parts: suggestion
310+
.into_iter()
311+
.map(|(span, snippet)| SubstitutionPart { snippet, span })
312+
.collect(),
313+
})
314+
.collect(),
315+
msg: msg.to_owned(),
316+
style: SuggestionStyle::ShowCode,
317+
applicability,
318+
});
319+
self
320+
}
321+
299322
/// Prints out a message with for a multipart suggestion without showing the suggested code.
300323
///
301324
/// This is intended to be used for suggestions that are obvious in what the changes need to

‎src/librustc_errors/diagnostic_builder.rs‎

Lines changed: 13 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -260,6 +260,19 @@ impl<'a> DiagnosticBuilder<'a> {
260260
self
261261
}
262262

263+
pub fn multipart_suggestions(
264+
&mut self,
265+
msg: &str,
266+
suggestions: Vec<Vec<(Span, String)>>,
267+
applicability: Applicability,
268+
) -> &mut Self {
269+
if !self.0.allow_suggestions {
270+
return self;
271+
}
272+
self.0.diagnostic.multipart_suggestions(msg, suggestions, applicability);
273+
self
274+
}
275+
263276
pub fn tool_only_multipart_suggestion(
264277
&mut self,
265278
msg: &str,

‎src/librustc_middle/ty/util.rs‎

Lines changed: 9 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -827,7 +827,15 @@ impl<'tcx> ty::TyS<'tcx> {
827827
// Find non representable fields with their spans
828828
fold_repr(def.all_fields().map(|field| {
829829
let ty = field.ty(tcx, substs);
830-
let span = tcx.hir().span_if_local(field.did).unwrap_or(sp);
830+
let span = match field
831+
.did
832+
.as_local()
833+
.map(|id| tcx.hir().as_local_hir_id(id))
834+
.and_then(|id| tcx.hir().find(id))
835+
{
836+
Some(hir::Node::Field(field)) => field.ty.span,
837+
_ => sp,
838+
};
831839
match is_type_structurally_recursive(
832840
tcx,
833841
span,

‎src/librustc_trait_selection/traits/error_reporting/mod.rs‎

Lines changed: 52 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -1747,24 +1747,62 @@ impl<'a, 'tcx> InferCtxtPrivExt<'tcx> for InferCtxt<'a, 'tcx> {
17471747
pub fn recursive_type_with_infinite_size_error(
17481748
tcx: TyCtxt<'tcx>,
17491749
type_def_id: DefId,
1750-
) -> DiagnosticBuilder<'tcx> {
1750+
spans: Vec<Span>,
1751+
) {
17511752
assert!(type_def_id.is_local());
17521753
let span = tcx.hir().span_if_local(type_def_id).unwrap();
17531754
let span = tcx.sess.source_map().guess_head_span(span);
1754-
let mut err = struct_span_err!(
1755-
tcx.sess,
1756-
span,
1757-
E0072,
1758-
"recursive type `{}` has infinite size",
1759-
tcx.def_path_str(type_def_id)
1760-
);
1755+
let path = tcx.def_path_str(type_def_id);
1756+
let mut err =
1757+
struct_span_err!(tcx.sess, span, E0072, "recursive type `{}` has infinite size", path);
17611758
err.span_label(span, "recursive type has infinite size");
1762-
err.help(&format!(
1763-
"insert indirection (e.g., a `Box`, `Rc`, or `&`) \
1764-
at some point to make `{}` representable",
1765-
tcx.def_path_str(type_def_id)
1766-
));
1767-
err
1759+
for &span in &spans {
1760+
err.span_label(span, "recursive without indirection");
1761+
}
1762+
let short_msg = format!("insert some indirection to make `{}` representable", path);
1763+
let msg = format!(
1764+
"insert some indirection (e.g., a `Box`, `Rc`, or `&`) to make `{}` representable",
1765+
path,
1766+
);
1767+
match &spans[..] {
1768+
[span] => {
1769+
err.multipart_suggestions(
1770+
&short_msg,
1771+
vec![
1772+
vec![
1773+
(span.shrink_to_lo(), "Box<".to_string()),
1774+
(span.shrink_to_hi(), ">".to_string()),
1775+
],
1776+
vec![
1777+
(span.shrink_to_lo(), "Rc<".to_string()),
1778+
(span.shrink_to_hi(), ">".to_string()),
1779+
],
1780+
vec![(span.shrink_to_lo(), "&".to_string())],
1781+
],
1782+
Applicability::HasPlaceholders,
1783+
);
1784+
}
1785+
_ if spans.len() <= 4 => {
1786+
err.multipart_suggestion(
1787+
&msg,
1788+
spans
1789+
.iter()
1790+
.flat_map(|&span| {
1791+
vec![
1792+
(span.shrink_to_lo(), "Box<".to_string()),
1793+
(span.shrink_to_hi(), ">".to_string()),
1794+
]
1795+
.into_iter()
1796+
})
1797+
.collect(),
1798+
Applicability::HasPlaceholders,
1799+
);
1800+
}
1801+
_ => {
1802+
err.help(&msg);
1803+
}
1804+
}
1805+
err.emit();
17681806
}
17691807

17701808
/// Summarizes information

‎src/librustc_typeck/check/mod.rs‎

Lines changed: 1 addition & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -2390,11 +2390,7 @@ fn check_representable(tcx: TyCtxt<'_>, sp: Span, item_def_id: LocalDefId) -> bo
23902390
// caught by case 1.
23912391
match rty.is_representable(tcx, sp) {
23922392
Representability::SelfRecursive(spans) => {
2393-
let mut err = recursive_type_with_infinite_size_error(tcx, item_def_id.to_def_id());
2394-
for span in spans {
2395-
err.span_label(span, "recursive without indirection");
2396-
}
2397-
err.emit();
2393+
recursive_type_with_infinite_size_error(tcx, item_def_id.to_def_id(), spans);
23982394
return false;
23992395
}
24002396
Representability::Representable | Representability::ContainsRecursive => (),

‎src/test/ui/infinite/infinite-tag-type-recursion.stderr‎

Lines changed: 8 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -6,7 +6,14 @@ LL | enum MList { Cons(isize, MList), Nil }
66
| |
77
| recursive type has infinite size
88
|
9-
= help: insert indirection (e.g., a `Box`, `Rc`, or `&`) at some point to make `MList` representable
9+
help: insert some indirection to make `MList` representable
10+
|
11+
LL | enum MList { Cons(isize, Box<MList>), Nil }
12+
| ^^^^ ^
13+
LL | enum MList { Cons(isize, Rc<MList>), Nil }
14+
| ^^^ ^
15+
LL | enum MList { Cons(isize, &MList), Nil }
16+
| ^
1017

1118
error[E0391]: cycle detected when computing drop-check constraints for `MList`
1219
--> $DIR/infinite-tag-type-recursion.rs:1:1

‎src/test/ui/issues/issue-17431-1.stderr‎

Lines changed: 9 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -2,11 +2,18 @@ error[E0072]: recursive type `Foo` has infinite size
22
--> $DIR/issue-17431-1.rs:1:1
33
|
44
LL | struct Foo { foo: Option<Option<Foo>> }
5-
| ^^^^^^^^^^ ------------------------ recursive without indirection
5+
| ^^^^^^^^^^ ------------------- recursive without indirection
66
| |
77
| recursive type has infinite size
88
|
9-
= help: insert indirection (e.g., a `Box`, `Rc`, or `&`) at some point to make `Foo` representable
9+
help: insert some indirection to make `Foo` representable
10+
|
11+
LL | struct Foo { foo: Box<Option<Option<Foo>>> }
12+
| ^^^^ ^
13+
LL | struct Foo { foo: Rc<Option<Option<Foo>>> }
14+
| ^^^ ^
15+
LL | struct Foo { foo: &Option<Option<Foo>> }
16+
| ^
1017

1118
error: aborting due to previous error
1219

‎src/test/ui/issues/issue-17431-2.stderr‎

Lines changed: 18 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -2,21 +2,35 @@ error[E0072]: recursive type `Baz` has infinite size
22
--> $DIR/issue-17431-2.rs:1:1
33
|
44
LL | struct Baz { q: Option<Foo> }
5-
| ^^^^^^^^^^ -------------- recursive without indirection
5+
| ^^^^^^^^^^ ----------- recursive without indirection
66
| |
77
| recursive type has infinite size
88
|
9-
= help: insert indirection (e.g., a `Box`, `Rc`, or `&`) at some point to make `Baz` representable
9+
help: insert some indirection to make `Baz` representable
10+
|
11+
LL | struct Baz { q: Box<Option<Foo>> }
12+
| ^^^^ ^
13+
LL | struct Baz { q: Rc<Option<Foo>> }
14+
| ^^^ ^
15+
LL | struct Baz { q: &Option<Foo> }
16+
| ^
1017

1118
error[E0072]: recursive type `Foo` has infinite size
1219
--> $DIR/issue-17431-2.rs:4:1
1320
|
1421
LL | struct Foo { q: Option<Baz> }
15-
| ^^^^^^^^^^ -------------- recursive without indirection
22+
| ^^^^^^^^^^ ----------- recursive without indirection
1623
| |
1724
| recursive type has infinite size
1825
|
19-
= help: insert indirection (e.g., a `Box`, `Rc`, or `&`) at some point to make `Foo` representable
26+
help: insert some indirection to make `Foo` representable
27+
|
28+
LL | struct Foo { q: Box<Option<Baz>> }
29+
| ^^^^ ^
30+
LL | struct Foo { q: Rc<Option<Baz>> }
31+
| ^^^ ^
32+
LL | struct Foo { q: &Option<Baz> }
33+
| ^
2034

2135
error: aborting due to 2 previous errors
2236

‎src/test/ui/issues/issue-17431-3.stderr‎

Lines changed: 9 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -2,11 +2,18 @@ error[E0072]: recursive type `Foo` has infinite size
22
--> $DIR/issue-17431-3.rs:3:1
33
|
44
LL | struct Foo { foo: Mutex<Option<Foo>> }
5-
| ^^^^^^^^^^ ----------------------- recursive without indirection
5+
| ^^^^^^^^^^ ------------------ recursive without indirection
66
| |
77
| recursive type has infinite size
88
|
9-
= help: insert indirection (e.g., a `Box`, `Rc`, or `&`) at some point to make `Foo` representable
9+
help: insert some indirection to make `Foo` representable
10+
|
11+
LL | struct Foo { foo: Box<Mutex<Option<Foo>>> }
12+
| ^^^^ ^
13+
LL | struct Foo { foo: Rc<Mutex<Option<Foo>>> }
14+
| ^^^ ^
15+
LL | struct Foo { foo: &Mutex<Option<Foo>> }
16+
| ^
1017

1118
error: aborting due to previous error
1219

‎src/test/ui/issues/issue-17431-4.stderr‎

Lines changed: 9 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -2,11 +2,18 @@ error[E0072]: recursive type `Foo` has infinite size
22
--> $DIR/issue-17431-4.rs:3:1
33
|
44
LL | struct Foo<T> { foo: Option<Option<Foo<T>>>, marker: marker::PhantomData<T> }
5-
| ^^^^^^^^^^^^^ --------------------------- recursive without indirection
5+
| ^^^^^^^^^^^^^ ---------------------- recursive without indirection
66
| |
77
| recursive type has infinite size
88
|
9-
= help: insert indirection (e.g., a `Box`, `Rc`, or `&`) at some point to make `Foo` representable
9+
help: insert some indirection to make `Foo` representable
10+
|
11+
LL | struct Foo<T> { foo: Box<Option<Option<Foo<T>>>>, marker: marker::PhantomData<T> }
12+
| ^^^^ ^
13+
LL | struct Foo<T> { foo: Rc<Option<Option<Foo<T>>>>, marker: marker::PhantomData<T> }
14+
| ^^^ ^
15+
LL | struct Foo<T> { foo: &Option<Option<Foo<T>>>, marker: marker::PhantomData<T> }
16+
| ^
1017

1118
error: aborting due to previous error
1219

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