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Rollup merge of #73320 - estebank:type-param-sugg-more, r=davidtwco

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Make new type param suggestion more targetted

Do not suggest new type param when encountering a missing type in an ADT
field with generic parameters.

Fix #72640.
This commit is contained in:
Manish Goregaokar 2020-06-18 15:20:55 -07:00 committed by GitHub
commit f4b5f581a9
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GPG Key ID: 4AEE18F83AFDEB23
6 changed files with 80 additions and 15 deletions
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1
src/librustc_resolve/build_reduced_graph.rs
View File

@ -485,6 +485,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
module_path.push(Segment {
ident: Ident { name: kw::PathRoot, span: source.ident.span },
id: Some(self.r.next_node_id()),
has_generic_args: false,
});
source.ident.name = crate_name;
}

43
src/librustc_resolve/late/diagnostics.rs
View File

@ -920,20 +920,47 @@ impl<'a> LateResolutionVisitor<'a, '_, '_> {
&self,
path: &[Segment],
) -> Option<(Span, &'static str, String, Applicability)> {
let ident = match path {
[segment] => segment.ident,
let (ident, span) = match path {
[segment] if !segment.has_generic_args => {
(segment.ident.to_string(), segment.ident.span)
}
_ => return None,
};
match (
self.diagnostic_metadata.current_item,
self.diagnostic_metadata.currently_processing_generics,
) {
(Some(Item { kind: ItemKind::Fn(..), ident, .. }), true) if ident.name == sym::main => {
let mut iter = ident.chars().map(|c| c.is_uppercase());
let single_uppercase_char =
matches!(iter.next(), Some(true)) && matches!(iter.next(), None);
if !self.diagnostic_metadata.currently_processing_generics && !single_uppercase_char {
return None;
}
match (self.diagnostic_metadata.current_item, single_uppercase_char) {
(Some(Item { kind: ItemKind::Fn(..), ident, .. }), _) if ident.name == sym::main => {
// Ignore `fn main()` as we don't want to suggest `fn main<T>()`
}
(Some(Item { kind, .. }), true) => {
(
Some(Item {
kind:
kind @ ItemKind::Fn(..)
| kind @ ItemKind::Enum(..)
| kind @ ItemKind::Struct(..)
| kind @ ItemKind::Union(..),
..
}),
true,
)
| (Some(Item { kind, .. }), false) => {
// Likely missing type parameter.
if let Some(generics) = kind.generics() {
if span.overlaps(generics.span) {
// Avoid the following:
// error[E0405]: cannot find trait `A` in this scope
// --> $DIR/typo-suggestion-named-underscore.rs:CC:LL
// |
// L | fn foo<T: A>(x: T) {} // Shouldn't suggest underscore
// | ^- help: you might be missing a type parameter: `, A`
// | |
// | not found in this scope
return None;
}
let msg = "you might be missing a type parameter";
let (span, sugg) = if let [.., param] = &generics.params[..] {
let span = if let [.., bound] = &param.bounds[..] {

14
src/librustc_resolve/lib.rs
View File

@ -225,13 +225,15 @@ enum VisResolutionError<'a> {
ModuleOnly(Span),
}
// A minimal representation of a path segment. We use this in resolve because
// we synthesize 'path segments' which don't have the rest of an AST or HIR
// `PathSegment`.
/// A minimal representation of a path segment. We use this in resolve because we synthesize 'path
/// segments' which don't have the rest of an AST or HIR `PathSegment`.
#[derive(Clone, Copy, Debug)]
pub struct Segment {
ident: Ident,
id: Option<NodeId>,
/// Signals whether this `PathSegment` has generic arguments. Used to avoid providing
/// nonsensical suggestions.
has_generic_args: bool,
}
impl Segment {
@ -240,7 +242,7 @@ impl Segment {
}
fn from_ident(ident: Ident) -> Segment {
Segment { ident, id: None }
Segment { ident, id: None, has_generic_args: false }
}
fn names_to_string(segments: &[Segment]) -> String {
@ -250,7 +252,7 @@ impl Segment {
impl<'a> From<&'a ast::PathSegment> for Segment {
fn from(seg: &'a ast::PathSegment) -> Segment {
Segment { ident: seg.ident, id: Some(seg.id) }
Segment { ident: seg.ident, id: Some(seg.id), has_generic_args: seg.args.is_some() }
}
}
@ -2017,7 +2019,7 @@ impl<'a> Resolver<'a> {
path, opt_ns, record_used, path_span, crate_lint,
);
for (i, &Segment { ident, id }) in path.iter().enumerate() {
for (i, &Segment { ident, id, has_generic_args: _ }) in path.iter().enumerate() {
debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
let record_segment_res = |this: &mut Self, res| {
if record_used {

11
src/test/ui/associated-types/associated-types-eq-1.stderr
View File

@ -4,7 +4,16 @@ error[E0412]: cannot find type `A` in this scope
LL | fn foo2<I: Foo>(x: I) {
| - similarly named type parameter `I` defined here
LL | let _: A = x.boo();
| ^ help: a type parameter with a similar name exists: `I`
| ^
|
help: a type parameter with a similar name exists
|
LL | let _: I = x.boo();
| ^
help: you might be missing a type parameter
|
LL | fn foo2<I: Foo, A>(x: I) {
| ^^^
error: aborting due to previous error

9
src/test/ui/suggestions/type-not-found-in-adt-field.rs Normal file
View File

@ -0,0 +1,9 @@
struct Struct {
m: Vec<Someunknownname<String, ()>>, //~ ERROR cannot find type `Someunknownname` in this scope
//~^ NOTE not found in this scope
}
struct OtherStruct { //~ HELP you might be missing a type parameter
m: K, //~ ERROR cannot find type `K` in this scope
//~^ NOTE not found in this scope
}
fn main() {}

17
src/test/ui/suggestions/type-not-found-in-adt-field.stderr Normal file
View File

@ -0,0 +1,17 @@
error[E0412]: cannot find type `Someunknownname` in this scope
--> $DIR/type-not-found-in-adt-field.rs:2:12
|
LL | m: Vec<Someunknownname<String, ()>>,
| ^^^^^^^^^^^^^^^ not found in this scope
error[E0412]: cannot find type `K` in this scope
--> $DIR/type-not-found-in-adt-field.rs:6:8
|
LL | struct OtherStruct {
| - help: you might be missing a type parameter: `<K>`
LL | m: K,
| ^ not found in this scope
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0412`.