Rollup of 8 pull requests

compiler/rustc_builtin_macros/src/deriving/bounds.rs

@@ -16,6 +16,7 @@ pub fn expand_deriving_copy(
     let trait_def = TraitDef {
         span,
         path: path_std!(marker::Copy),
+        skip_path_as_bound: false,
         additional_bounds: Vec::new(),
         generics: Bounds::empty(),
         supports_unions: true,

compiler/rustc_builtin_macros/src/deriving/clone.rs

@@ -72,6 +72,7 @@ pub fn expand_deriving_clone(
     let trait_def = TraitDef {
         span,
         path: path_std!(clone::Clone),
+        skip_path_as_bound: false,
         additional_bounds: bounds,
         generics: Bounds::empty(),
         supports_unions: true,

compiler/rustc_builtin_macros/src/deriving/cmp/eq.rs

@@ -25,6 +25,7 @@ pub fn expand_deriving_eq(
     let trait_def = TraitDef {
         span,
         path: path_std!(cmp::Eq),
+        skip_path_as_bound: false,
         additional_bounds: Vec::new(),
         generics: Bounds::empty(),
         supports_unions: true,

compiler/rustc_builtin_macros/src/deriving/cmp/ord.rs

@@ -19,6 +19,7 @@ pub fn expand_deriving_ord(
     let trait_def = TraitDef {
         span,
         path: path_std!(cmp::Ord),
+        skip_path_as_bound: false,
         additional_bounds: Vec::new(),
         generics: Bounds::empty(),
         supports_unions: false,

compiler/rustc_builtin_macros/src/deriving/cmp/partial_eq.rs

@@ -83,6 +83,7 @@ pub fn expand_deriving_partial_eq(
     let trait_def = TraitDef {
         span,
         path: path_std!(cmp::PartialEq),
+        skip_path_as_bound: false,
         additional_bounds: Vec::new(),
         generics: Bounds::empty(),
         supports_unions: false,

compiler/rustc_builtin_macros/src/deriving/cmp/partial_ord.rs

@@ -37,6 +37,7 @@ pub fn expand_deriving_partial_ord(
     let trait_def = TraitDef {
         span,
         path: path_std!(cmp::PartialOrd),
+        skip_path_as_bound: false,
         additional_bounds: vec![],
         generics: Bounds::empty(),
         supports_unions: false,

compiler/rustc_builtin_macros/src/deriving/debug.rs

@@ -20,6 +20,7 @@ pub fn expand_deriving_debug(
     let trait_def = TraitDef {
         span,
         path: path_std!(fmt::Debug),
+        skip_path_as_bound: false,
         additional_bounds: Vec::new(),
         generics: Bounds::empty(),
         supports_unions: false,

compiler/rustc_builtin_macros/src/deriving/decodable.rs

@@ -23,6 +23,7 @@ pub fn expand_deriving_rustc_decodable(
     let trait_def = TraitDef {
         span,
         path: Path::new_(vec![krate, sym::Decodable], vec![], PathKind::Global),
+        skip_path_as_bound: false,
         additional_bounds: Vec::new(),
         generics: Bounds::empty(),
         supports_unions: false,

compiler/rustc_builtin_macros/src/deriving/default.rs

@@ -24,6 +24,7 @@ pub fn expand_deriving_default(
     let trait_def = TraitDef {
         span,
         path: Path::new(vec![kw::Default, sym::Default]),
+        skip_path_as_bound: has_a_default_variant(item),
         additional_bounds: Vec::new(),
         generics: Bounds::empty(),
         supports_unions: false,
@@ -262,3 +263,22 @@ impl<'a, 'b> rustc_ast::visit::Visitor<'a> for DetectNonVariantDefaultAttr<'a, '
         }
     }
 }
+
+fn has_a_default_variant(item: &Annotatable) -> bool {
+    struct HasDefaultAttrOnVariant {
+        found: bool,
+    }
+
+    impl<'ast> rustc_ast::visit::Visitor<'ast> for HasDefaultAttrOnVariant {
+        fn visit_variant(&mut self, v: &'ast rustc_ast::Variant) {
+            if v.attrs.iter().any(|attr| attr.has_name(kw::Default)) {
+                self.found = true;
+            }
+            // no need to subrecurse.
+        }
+    }
+
+    let mut visitor = HasDefaultAttrOnVariant { found: false };
+    item.visit_with(&mut visitor);
+    visitor.found
+}

compiler/rustc_builtin_macros/src/deriving/encodable.rs

@@ -107,6 +107,7 @@ pub fn expand_deriving_rustc_encodable(
     let trait_def = TraitDef {
         span,
         path: Path::new_(vec![krate, sym::Encodable], vec![], PathKind::Global),
+        skip_path_as_bound: false,
         additional_bounds: Vec::new(),
         generics: Bounds::empty(),
         supports_unions: false,

compiler/rustc_builtin_macros/src/deriving/generic/mod.rs

@@ -174,6 +174,7 @@ use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::Span;
 use std::cell::RefCell;
 use std::iter;
+use std::ops::Not;
 use std::vec;
 use thin_vec::thin_vec;
 use ty::{Bounds, Path, Ref, Self_, Ty};
@@ -187,6 +188,9 @@ pub struct TraitDef<'a> {
     /// Path of the trait, including any type parameters
     pub path: Path,
 
+    /// Whether to skip adding the current trait as a bound to the type parameters of the type.
+    pub skip_path_as_bound: bool,
+
     /// Additional bounds required of any type parameters of the type,
     /// other than the current trait
     pub additional_bounds: Vec<Ty>,
@@ -596,7 +600,7 @@ impl<'a> TraitDef<'a> {
                         cx.trait_bound(p.to_path(cx, self.span, type_ident, generics))
                     }).chain(
                         // require the current trait
-                        iter::once(cx.trait_bound(trait_path.clone()))
+                        self.skip_path_as_bound.not().then(|| cx.trait_bound(trait_path.clone()))
                     ).chain(
                         // also add in any bounds from the declaration
                         param.bounds.iter().cloned()

compiler/rustc_builtin_macros/src/deriving/hash.rs

@@ -22,6 +22,7 @@ pub fn expand_deriving_hash(
     let hash_trait_def = TraitDef {
         span,
         path,
+        skip_path_as_bound: false,
         additional_bounds: Vec::new(),
         generics: Bounds::empty(),
         supports_unions: false,

compiler/rustc_error_messages/locales/en-US/middle.ftl

@@ -15,3 +15,6 @@ middle_previous_use_here =
 middle_limit_invalid =
     `limit` must be a non-negative integer
     .label = {$error_str}
+
+middle_const_eval_non_int =
+    constant evaluation of enum discriminant resulted in non-integer

compiler/rustc_middle/src/error.rs

@@ -48,3 +48,10 @@ pub struct LimitInvalid<'a> {
     pub value_span: Span,
     pub error_str: &'a str,
 }
+
+#[derive(Diagnostic)]
+#[diag(middle::const_eval_non_int)]
+pub struct ConstEvalNonIntError {
+    #[primary_span]
+    pub span: Span,
+}

compiler/rustc_middle/src/ty/adt.rs

@@ -458,11 +458,9 @@ impl<'tcx> AdtDef<'tcx> {
                     Some(Discr { val: b, ty })
                 } else {
                     info!("invalid enum discriminant: {:#?}", val);
-                    crate::mir::interpret::struct_error(
-                        tcx.at(tcx.def_span(expr_did)),
-                        "constant evaluation of enum discriminant resulted in non-integer",
-                    )
-                    .emit();
+                    tcx.sess.emit_err(crate::error::ConstEvalNonIntError {
+                        span: tcx.def_span(expr_did),
+                    });
                     None
                 }
             }

library/alloc/src/lib.rs

@@ -230,8 +230,10 @@ pub mod collections;
 #[cfg(all(not(no_rc), not(no_sync), not(no_global_oom_handling)))]
 pub mod ffi;
 pub mod fmt;
+pub mod option;
 #[cfg(not(no_rc))]
 pub mod rc;
+pub mod result;
 pub mod slice;
 pub mod str;
 pub mod string;