Rollup merge of rust-lang#103531 - chenyukang:yukang/fix-103474, r=es…

…tebank

Suggest calling the instance method of the same name when method not found

Fixes rust-lang#103474

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -219,26 +219,26 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
  let (mod_prefix, mod_str, suggestion) = if path.len() == 1 {
  debug!(?self.diagnostic_metadata.current_impl_items);
  debug!(?self.diagnostic_metadata.current_function);
- let suggestion = if let Some(items) = self.diagnostic_metadata.current_impl_items
+ let suggestion = if self.current_trait_ref.is_none()
  && let Some((fn_kind, _)) = self.diagnostic_metadata.current_function
- && self.current_trait_ref.is_none()
  && let Some(FnCtxt::Assoc(_)) = fn_kind.ctxt()
+ && let Some(items) = self.diagnostic_metadata.current_impl_items
  && let Some(item) = items.iter().find(|i| {
- if let AssocItemKind::Fn(fn_) = &i.kind
- && !fn_.sig.decl.has_self()
- && i.ident.name == item_str.name
+ if let AssocItemKind::Fn(_) = &i.kind && i.ident.name == item_str.name
  {
  debug!(?item_str.name);
- debug!(?fn_.sig.decl.inputs);
  return true
  }
  false
  })
+ && let AssocItemKind::Fn(fn_) = &item.kind
  {
+ debug!(?fn_);
+ let self_sugg = if fn_.sig.decl.has_self() { "self." } else { "Self::" };
  Some((
- item_span,
+ item_span.shrink_to_lo(),
  "consider using the associated function",
- format!("Self::{}", item.ident)
+ self_sugg.to_string()
  ))
  } else {
  None
@@ -396,11 +396,13 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
  }
 
  fn suggest_self_or_self_ref(&mut self, err: &mut Diagnostic, path: &[Segment], span: Span) {
- let is_assoc_fn = self.self_type_is_available();
+ if !self.self_type_is_available() {
+ return;
+ }
  let Some(path_last_segment) = path.last() else { return };
  let item_str = path_last_segment.ident;
  // Emit help message for fake-self from other languages (e.g., `this` in Javascript).
- if ["this", "my"].contains(&item_str.as_str()) && is_assoc_fn {
+ if ["this", "my"].contains(&item_str.as_str()) {
  err.span_suggestion_short(
  span,
  "you might have meant to use `self` here instead",
@@ -451,7 +453,6 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
  let is_enum_variant = &|res| matches!(res, Res::Def(DefKind::Variant, _));
  let path_str = Segment::names_to_string(path);
  let ident_span = path.last().map_or(span, |ident| ident.ident.span);
-
  let mut candidates = self
  .r
  .lookup_import_candidates(ident, ns, &self.parent_scope, is_expected)
@@ -1542,7 +1543,6 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
  _ => None,
  }
  }
-
  // Fields are generally expected in the same contexts as locals.
  if filter_fn(Res::Local(ast::DUMMY_NODE_ID)) {
  if let Some(node_id) =

src/test/ui/resolve/issue-103474.rs

@@ -0,0 +1,28 @@
+struct S {}
+impl S {
+ fn first(&self) {}
+
+ fn second(&self) {
+ first()
+ //~^ ERROR cannot find function `first` in this scope
+ }
+
+ fn third(&self) {
+ no_method_err()
+ //~^ ERROR cannot find function `no_method_err` in this scope
+ }
+}
+
+// https://github.com/rust-lang/rust/pull/103531#discussion_r1004728080
+struct Foo {
+ i: i32,
+}
+
+impl Foo {
+ fn needs_self() {
+ this.i
+ //~^ ERROR cannot find value `this` in this scope
+ }
+}
+
+fn main() {}

src/test/ui/resolve/issue-103474.stderr

@@ -0,0 +1,35 @@
+error[E0425]: cannot find value `this` in this scope
+ --> $DIR/issue-103474.rs:23:9
+ |
+LL | this.i
+ | ^^^^ not found in this scope
+ |
+help: you might have meant to use `self` here instead
+ |
+LL | self.i
+ | ~~~~
+help: if you meant to use `self`, you are also missing a `self` receiver argument
+ |
+LL | fn needs_self(&self) {
+ | +++++
+
+error[E0425]: cannot find function `first` in this scope
+ --> $DIR/issue-103474.rs:6:9
+ |
+LL | first()
+ | ^^^^^ not found in this scope
+ |
+help: consider using the associated function
+ |
+LL | self.first()
+ | +++++
+
+error[E0425]: cannot find function `no_method_err` in this scope
+ --> $DIR/issue-103474.rs:11:9
+ |
+LL | no_method_err()
+ | ^^^^^^^^^^^^^ not found in this scope
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0425`.

src/test/ui/resolve/issue-2356.stderr

@@ -85,7 +85,7 @@ LL | static_method();
 help: consider using the associated function
  |
 LL | Self::static_method();
- | ~~~~~~~~~~~~~~~~~~~
+ | ++++++
 
 error[E0425]: cannot find function `purr` in this scope
  --> $DIR/issue-2356.rs:54:9
@@ -114,7 +114,7 @@ LL | grow_older();
 help: consider using the associated function
  |
 LL | Self::grow_older();
- | ~~~~~~~~~~~~~~~~
+ | ++++++
 
 error[E0425]: cannot find function `shave` in this scope
  --> $DIR/issue-2356.rs:74:5

src/test/ui/self/class-missing-self.stderr

@@ -10,6 +10,10 @@ error[E0425]: cannot find function `sleep` in this scope
 LL | sleep();
  | ^^^^^ not found in this scope
  |
+help: consider using the associated function
+ |
+LL | self.sleep();
+ | +++++
 help: consider importing this function
  |
 LL | use std::thread::sleep;

src/test/ui/suggestions/assoc_fn_without_self.stderr

@@ -7,13 +7,18 @@ LL | foo();
 help: consider using the associated function
  |
 LL | Self::foo();
- | ~~~~~~~~~
+ | ++++++
 
 error[E0425]: cannot find function `bar` in this scope
  --> $DIR/assoc_fn_without_self.rs:17:9
  |
 LL | bar();
  | ^^^ not found in this scope
+ |
+help: consider using the associated function
+ |
+LL | self.bar();
+ | +++++
 
 error[E0425]: cannot find function `baz` in this scope
  --> $DIR/assoc_fn_without_self.rs:18:9
@@ -24,7 +29,7 @@ LL | baz(2, 3);
 help: consider using the associated function
  |
 LL | Self::baz(2, 3);
- | ~~~~~~~~~
+ | ++++++
 
 error[E0425]: cannot find function `foo` in this scope
  --> $DIR/assoc_fn_without_self.rs:14:13