Rollup merge of rust-lang#118245 - fee1-dead-contrib:span-tilde-const, r=compiler-errors

Add `Span` to `TraitBoundModifier`

This improves diagnostics for the message "`~const` is not allowed here", and also fixes the span that we use when desugaring `~const Tr` into `Tr<host>` in effects desugaring.

Author: compiler-errors

compiler/rustc_ast/src/ast.rs

@@ -301,7 +301,7 @@ pub enum TraitBoundModifier {
     Maybe,
 
     /// `~const Trait`
-    MaybeConst,
+    MaybeConst(Span),
 
     /// `~const !Trait`
     //
@@ -317,8 +317,7 @@ pub enum TraitBoundModifier {
 impl TraitBoundModifier {
     pub fn to_constness(self) -> Const {
         match self {
-            // FIXME(effects) span
-            Self::MaybeConst => Const::Yes(DUMMY_SP),
+            Self::MaybeConst(span) => Const::Yes(span),
             _ => Const::No,
         }
     }
@@ -3155,7 +3154,7 @@ mod size_asserts {
     static_assert_size!(ForeignItem, 96);
     static_assert_size!(ForeignItemKind, 24);
     static_assert_size!(GenericArg, 24);
-    static_assert_size!(GenericBound, 56);
+    static_assert_size!(GenericBound, 64);
     static_assert_size!(Generics, 40);
     static_assert_size!(Impl, 136);
     static_assert_size!(Item, 136);

compiler/rustc_ast_lowering/src/lib.rs

@@ -1369,7 +1369,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                             GenericBound::Trait(
                                 ty,
                                 modifier @ (TraitBoundModifier::None
-                                | TraitBoundModifier::MaybeConst
+                                | TraitBoundModifier::MaybeConst(_)
                                 | TraitBoundModifier::Negative),
                             ) => {
                                 Some(this.lower_poly_trait_ref(ty, itctx, modifier.to_constness()))
@@ -2227,7 +2227,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     fn lower_trait_bound_modifier(&mut self, f: TraitBoundModifier) -> hir::TraitBoundModifier {
         match f {
             TraitBoundModifier::None => hir::TraitBoundModifier::None,
-            TraitBoundModifier::MaybeConst => hir::TraitBoundModifier::MaybeConst,
+            TraitBoundModifier::MaybeConst(_) => hir::TraitBoundModifier::MaybeConst,
 
             TraitBoundModifier::Negative => {
                 if self.tcx.features().negative_bounds {

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -1203,7 +1203,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                 (BoundKind::TraitObject, TraitBoundModifier::Maybe) => {
                     self.err_handler().emit_err(errors::OptionalTraitObject { span: poly.span });
                 }
-                (_, TraitBoundModifier::MaybeConst)
+                (_, &TraitBoundModifier::MaybeConst(span))
                     if let Some(reason) = &self.disallow_tilde_const =>
                 {
                     let reason = match reason {
@@ -1224,8 +1224,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                         }
                         DisallowTildeConstContext::Item => errors::TildeConstReason::Item,
                     };
-                    self.err_handler()
-                        .emit_err(errors::TildeConstDisallowed { span: bound.span(), reason });
+                    self.err_handler().emit_err(errors::TildeConstDisallowed { span, reason });
                 }
                 (_, TraitBoundModifier::MaybeConstMaybe) => {
                     self.err_handler().emit_err(errors::OptionalConstExclusive {

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -1515,7 +1515,7 @@ impl<'a> State<'a> {
                         TraitBoundModifier::Maybe => {
                             self.word("?");
                         }
-                        TraitBoundModifier::MaybeConst => {
+                        TraitBoundModifier::MaybeConst(_) => {
                             self.word_space("~const");
                         }
                         TraitBoundModifier::MaybeConstNegative => {

compiler/rustc_expand/src/build.rs

@@ -4,7 +4,7 @@ use rustc_ast::{self as ast, AttrVec, BlockCheckMode, Expr, LocalKind, PatKind,
 use rustc_ast::{attr, token, util::literal};
 use rustc_span::source_map::Spanned;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
-use rustc_span::Span;
+use rustc_span::{Span, DUMMY_SP};
 use thin_vec::{thin_vec, ThinVec};
 
 impl<'a> ExtCtxt<'a> {
@@ -135,7 +135,7 @@ impl<'a> ExtCtxt<'a> {
         ast::GenericBound::Trait(
             self.poly_trait_ref(path.span, path),
             if is_const {
-                ast::TraitBoundModifier::MaybeConst
+                ast::TraitBoundModifier::MaybeConst(DUMMY_SP)
             } else {
                 ast::TraitBoundModifier::None
             },

compiler/rustc_parse/src/parser/ty.rs

@@ -37,7 +37,7 @@ impl BoundModifiers {
             (BoundPolarity::Positive, None) => TraitBoundModifier::None,
             (BoundPolarity::Negative(_), None) => TraitBoundModifier::Negative,
             (BoundPolarity::Maybe(_), None) => TraitBoundModifier::Maybe,
-            (BoundPolarity::Positive, Some(_)) => TraitBoundModifier::MaybeConst,
+            (BoundPolarity::Positive, Some(sp)) => TraitBoundModifier::MaybeConst(sp),
             (BoundPolarity::Negative(_), Some(_)) => TraitBoundModifier::MaybeConstNegative,
             (BoundPolarity::Maybe(_), Some(_)) => TraitBoundModifier::MaybeConstMaybe,
         }

src/tools/rustfmt/src/types.rs

@@ -546,7 +546,7 @@ impl Rewrite for ast::GenericBound {
                     ast::TraitBoundModifier::Maybe => poly_trait_ref
                         .rewrite(context, shape.offset_left(1)?)
                         .map(|s| format!("?{}", s)),
-                    ast::TraitBoundModifier::MaybeConst => poly_trait_ref
+                    ast::TraitBoundModifier::MaybeConst(_) => poly_trait_ref
                         .rewrite(context, shape.offset_left(7)?)
                         .map(|s| format!("~const {}", s)),
                     ast::TraitBoundModifier::MaybeConstMaybe => poly_trait_ref

tests/ui/rfcs/rfc-2632-const-trait-impl/assoc-type-const-bound-usage.stderr

@@ -2,7 +2,7 @@ error: `~const` is not allowed here
   --> $DIR/assoc-type-const-bound-usage.rs:7:17
    |
 LL |     type Assoc: ~const Foo;
-   |                 ^^^^^^^^^^
+   |                 ^^^^^^
    |
    = note: this item cannot have `~const` trait bounds
 

tests/ui/rfcs/rfc-2632-const-trait-impl/assoc-type.stderr

@@ -2,7 +2,7 @@ error: `~const` is not allowed here
   --> $DIR/assoc-type.rs:17:15
    |
 LL |     type Bar: ~const std::ops::Add;
-   |               ^^^^^^^^^^^^^^^^^^^^
+   |               ^^^^^^
    |
    = note: this item cannot have `~const` trait bounds
 

tests/ui/rfcs/rfc-2632-const-trait-impl/const-bound-on-not-const-associated-fn.stderr

@@ -2,7 +2,7 @@ error: `~const` is not allowed here
   --> $DIR/const-bound-on-not-const-associated-fn.rs:9:40
    |
 LL |     fn do_something_else() where Self: ~const MyTrait;
-   |                                        ^^^^^^^^^^^^^^
+   |                                        ^^^^^^
    |
 note: this function is not `const`, so it cannot have `~const` trait bounds
   --> $DIR/const-bound-on-not-const-associated-fn.rs:9:8
@@ -14,7 +14,7 @@ error: `~const` is not allowed here
   --> $DIR/const-bound-on-not-const-associated-fn.rs:20:32
    |
 LL |     pub fn foo(&self) where T: ~const MyTrait {
-   |                                ^^^^^^^^^^^^^^
+   |                                ^^^^^^
    |
 note: this function is not `const`, so it cannot have `~const` trait bounds
   --> $DIR/const-bound-on-not-const-associated-fn.rs:20:12