Auto merge of rust-lang#98284 - JohnTitor:rollup-7lbs143, r=JohnTitor

Rollup of 5 pull requests

Successful merges:

 - rust-lang#98183 (Fix pretty printing of empty bound lists in where-clause)
 - rust-lang#98268 (Improve `lifetime arguments are not allowed on` error message)
 - rust-lang#98273 (Fix minor documentation typo)
 - rust-lang#98274 (Minor improvements on error for `Self` type in items that don't allow it)
 - rust-lang#98281 (Fix typo in `HashMap::drain` docs)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -814,7 +814,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
     }
 
     fn bounds_to_string(&self, bounds: &[ast::GenericBound]) -> String {
-        Self::to_string(|s| s.print_type_bounds("", bounds))
+        Self::to_string(|s| s.print_type_bounds(bounds))
     }
 
     fn pat_to_string(&self, pat: &ast::Pat) -> String {
@@ -991,7 +991,12 @@ impl<'a> State<'a> {
                     Term::Const(c) => self.print_expr_anon_const(c, &[]),
                 }
             }
-            ast::AssocConstraintKind::Bound { bounds } => self.print_type_bounds(":", &*bounds),
+            ast::AssocConstraintKind::Bound { bounds } => {
+                if !bounds.is_empty() {
+                    self.word_nbsp(":");
+                    self.print_type_bounds(&bounds);
+                }
+            }
         }
     }
 
@@ -1045,11 +1050,14 @@ impl<'a> State<'a> {
             }
             ast::TyKind::Path(Some(ref qself), ref path) => self.print_qpath(path, qself, false),
             ast::TyKind::TraitObject(ref bounds, syntax) => {
-                let prefix = if syntax == ast::TraitObjectSyntax::Dyn { "dyn" } else { "" };
-                self.print_type_bounds(prefix, &bounds);
+                if syntax == ast::TraitObjectSyntax::Dyn {
+                    self.word_nbsp("dyn");
+                }
+                self.print_type_bounds(bounds);
             }
             ast::TyKind::ImplTrait(_, ref bounds) => {
-                self.print_type_bounds("impl", &bounds);
+                self.word_nbsp("impl");
+                self.print_type_bounds(bounds);
             }
             ast::TyKind::Array(ref ty, ref length) => {
                 self.word("[");
@@ -1549,29 +1557,24 @@ impl<'a> State<'a> {
         }
     }
 
-    pub fn print_type_bounds(&mut self, prefix: &'static str, bounds: &[ast::GenericBound]) {
-        if !bounds.is_empty() {
-            self.word(prefix);
-            let mut first = true;
-            for bound in bounds {
-                if !(first && prefix.is_empty()) {
-                    self.nbsp();
-                }
-                if first {
-                    first = false;
-                } else {
-                    self.word_space("+");
-                }
+    pub fn print_type_bounds(&mut self, bounds: &[ast::GenericBound]) {
+        let mut first = true;
+        for bound in bounds {
+            if first {
+                first = false;
+            } else {
+                self.nbsp();
+                self.word_space("+");
+            }
 
-                match bound {
-                    GenericBound::Trait(tref, modifier) => {
-                        if modifier == &TraitBoundModifier::Maybe {
-                            self.word("?");
-                        }
-                        self.print_poly_trait_ref(tref);
+            match bound {
+                GenericBound::Trait(tref, modifier) => {
+                    if modifier == &TraitBoundModifier::Maybe {
+                        self.word("?");
                     }
-                    GenericBound::Outlives(lt) => self.print_lifetime(*lt),
+                    self.print_poly_trait_ref(tref);
                 }
+                GenericBound::Outlives(lt) => self.print_lifetime(*lt),
             }
         }
     }
@@ -1580,22 +1583,14 @@ impl<'a> State<'a> {
         self.print_name(lifetime.ident.name)
     }
 
-    pub(crate) fn print_lifetime_bounds(
-        &mut self,
-        lifetime: ast::Lifetime,
-        bounds: &ast::GenericBounds,
-    ) {
-        self.print_lifetime(lifetime);
-        if !bounds.is_empty() {
-            self.word(": ");
-            for (i, bound) in bounds.iter().enumerate() {
-                if i != 0 {
-                    self.word(" + ");
-                }
-                match bound {
-                    ast::GenericBound::Outlives(lt) => self.print_lifetime(*lt),
-                    _ => panic!(),
-                }
+    pub(crate) fn print_lifetime_bounds(&mut self, bounds: &ast::GenericBounds) {
+        for (i, bound) in bounds.iter().enumerate() {
+            if i != 0 {
+                self.word(" + ");
+            }
+            match bound {
+                ast::GenericBound::Outlives(lt) => self.print_lifetime(*lt),
+                _ => panic!(),
             }
         }
     }
@@ -1613,11 +1608,18 @@ impl<'a> State<'a> {
             match param.kind {
                 ast::GenericParamKind::Lifetime => {
                     let lt = ast::Lifetime { id: param.id, ident: param.ident };
-                    s.print_lifetime_bounds(lt, &param.bounds)
+                    s.print_lifetime(lt);
+                    if !param.bounds.is_empty() {
+                        s.word_nbsp(":");
+                        s.print_lifetime_bounds(&param.bounds)
+                    }
                 }
                 ast::GenericParamKind::Type { ref default } => {
                     s.print_ident(param.ident);
-                    s.print_type_bounds(":", &param.bounds);
+                    if !param.bounds.is_empty() {
+                        s.word_nbsp(":");
+                        s.print_type_bounds(&param.bounds);
+                    }
                     if let Some(ref default) = default {
                         s.space();
                         s.word_space("=");
@@ -1630,7 +1632,10 @@ impl<'a> State<'a> {
                     s.space();
                     s.word_space(":");
                     s.print_type(ty);
-                    s.print_type_bounds(":", &param.bounds);
+                    if !param.bounds.is_empty() {
+                        s.word_nbsp(":");
+                        s.print_type_bounds(&param.bounds);
+                    }
                     if let Some(ref default) = default {
                         s.space();
                         s.word_space("=");

compiler/rustc_ast_pretty/src/pprust/state/item.rs

@@ -114,7 +114,10 @@ impl<'a> State<'a> {
         self.word_space("type");
         self.print_ident(ident);
         self.print_generic_params(&generics.params);
-        self.print_type_bounds(":", bounds);
+        if !bounds.is_empty() {
+            self.word_nbsp(":");
+            self.print_type_bounds(bounds);
+        }
         self.print_where_clause_parts(where_clauses.0.0, before_predicates);
         if let Some(ty) = ty {
             self.space();
@@ -320,7 +323,10 @@ impl<'a> State<'a> {
                         real_bounds.push(b.clone());
                     }
                 }
-                self.print_type_bounds(":", &real_bounds);
+                if !real_bounds.is_empty() {
+                    self.word_nbsp(":");
+                    self.print_type_bounds(&real_bounds);
+                }
                 self.print_where_clause(&generics.where_clause);
                 self.word(" ");
                 self.bopen();
@@ -347,7 +353,10 @@ impl<'a> State<'a> {
                     }
                 }
                 self.nbsp();
-                self.print_type_bounds("=", &real_bounds);
+                if !real_bounds.is_empty() {
+                    self.word_nbsp("=");
+                    self.print_type_bounds(&real_bounds);
+                }
                 self.print_where_clause(&generics.where_clause);
                 self.word(";");
                 self.end(); // end inner head-block
@@ -618,14 +627,23 @@ impl<'a> State<'a> {
             }) => {
                 self.print_formal_generic_params(bound_generic_params);
                 self.print_type(bounded_ty);
-                self.print_type_bounds(":", bounds);
+                self.word(":");
+                if !bounds.is_empty() {
+                    self.nbsp();
+                    self.print_type_bounds(bounds);
+                }
             }
             ast::WherePredicate::RegionPredicate(ast::WhereRegionPredicate {
                 lifetime,
                 bounds,
                 ..
             }) => {
-                self.print_lifetime_bounds(*lifetime, bounds);
+                self.print_lifetime(*lifetime);
+                self.word(":");
+                if !bounds.is_empty() {
+                    self.nbsp();
+                    self.print_lifetime_bounds(bounds);
+                }
             }
             ast::WherePredicate::EqPredicate(ast::WhereEqPredicate { lhs_ty, rhs_ty, .. }) => {
                 self.print_type(lhs_ty);

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -1355,7 +1355,10 @@ impl<'a> Parser<'a> {
                     s.print_mutability(mut_ty.mutbl, false);
                     s.popen();
                     s.print_type(&mut_ty.ty);
-                    s.print_type_bounds(" +", &bounds);
+                    if !bounds.is_empty() {
+                        s.word(" + ");
+                        s.print_type_bounds(&bounds);
+                    }
                     s.pclose()
                 });
 

compiler/rustc_resolve/src/diagnostics.rs

@@ -1914,6 +1914,8 @@ impl<'a> Resolver<'a> {
                 };
             }
             (msg, None)
+        } else if ident.name == kw::SelfUpper {
+            ("`Self` is only available in impls, traits, and type definitions".to_string(), None)
         } else if ident.name.as_str().chars().next().map_or(false, |c| c.is_ascii_uppercase()) {
             // Check whether the name refers to an item in the value namespace.
             let binding = if let Some(ribs) = ribs {

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -332,6 +332,16 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                 span,
                 "`Self` is only available in impls, traits, and type definitions".to_string(),
             );
+            if let Some(item_kind) = self.diagnostic_metadata.current_item {
+                err.span_label(
+                    item_kind.ident.span,
+                    format!(
+                        "`Self` not allowed in {} {}",
+                        item_kind.kind.article(),
+                        item_kind.kind.descr()
+                    ),
+                );
+            }
             return (err, Vec::new());
         }
         if is_self_value(path, ns) {
@@ -389,6 +399,15 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
                         );
                     }
                 }
+            } else if let Some(item_kind) = self.diagnostic_metadata.current_item {
+                err.span_label(
+                    item_kind.ident.span,
+                    format!(
+                        "`self` not allowed in {} {}",
+                        item_kind.kind.article(),
+                        item_kind.kind.descr()
+                    ),
+                );
             }
             return (err, Vec::new());
         }
@@ -1788,7 +1807,7 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
         path: &[Segment],
     ) -> Option<(Span, &'static str, String, Applicability)> {
         let (ident, span) = match path {
-            [segment] if !segment.has_generic_args => {
+            [segment] if !segment.has_generic_args && segment.ident.name != kw::SelfUpper => {
                 (segment.ident.to_string(), segment.ident.span)
             }
             _ => return None,

compiler/rustc_trait_selection/src/lib.rs

@@ -1,4 +1,4 @@
-//! This crates defines the trait resolution method.
+//! This crate defines the trait resolution method.
 //!
 //! - **Traits.** Trait resolution is implemented in the `traits` module.
 //!

compiler/rustc_typeck/src/astconv/mod.rs

@@ -2195,8 +2195,8 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 "{kind} arguments are not allowed on {this_type}",
             );
             err.span_label(last_span, format!("{kind} argument{s} not allowed"));
-            for (_, span) in types_and_spans {
-                err.span_label(span, "not allowed on this");
+            for (what, span) in types_and_spans {
+                err.span_label(span, format!("not allowed on {what}"));
             }
             extend(&mut err);
             err.emit();

library/std/src/collections/hash/map.rs

@@ -588,7 +588,7 @@ impl<K, V, S> HashMap<K, V, S> {
     ///
     /// If the returned iterator is dropped before being fully consumed, it
     /// drops the remaining key-value pairs. The returned iterator keeps a
-    /// mutable borrow on the vector to optimize its implementation.
+    /// mutable borrow on the map to optimize its implementation.
     ///
     /// # Examples
     ///

src/test/pretty/where-clauses.rs

@@ -2,4 +2,7 @@
 
 fn f<'a, 'b, T>(t: T) -> isize where T: 'a, 'a: 'b, T: Eq { 0 }
 
+// This is legal syntax, sometimes generated by macros. `where T: $($bound+)*`
+fn zero_bounds<'a, T>() where 'a:, T: {}
+
 fn main() {}

src/test/ui/derives/issue-97343.stderr

@@ -4,7 +4,7 @@ error[E0109]: type arguments are not allowed on type parameter `Irrelevant`
 LL | #[derive(Debug)]
    |          -----
    |          |
-   |          not allowed on this
+   |          not allowed on type parameter `Irrelevant`
    |          in this derive macro expansion
 LL | pub struct Irrelevant<Irrelevant> {
    |                       ^^^^^^^^^^ type argument not allowed