Rollup merge of #74357 - nnethercote:symbol-related-improvements, r=oli-obk

Some `Symbol` related improvements

These commits make things nicer and avoid some `Symbol::as_str()` calls.

r? @oli-obk

Author: Manishearth

src/librustc_builtin_macros/deriving/bounds.rs

@@ -16,9 +16,9 @@ pub fn expand_deriving_copy(
     let trait_def = TraitDef {
         span,
         attributes: Vec::new(),
-        path: path_std!(cx, marker::Copy),
+        path: path_std!(marker::Copy),
         additional_bounds: Vec::new(),
-        generics: LifetimeBounds::empty(),
+        generics: Bounds::empty(),
         is_unsafe: false,
         supports_unions: true,
         methods: Vec::new(),

src/librustc_builtin_macros/deriving/clone.rs

@@ -56,7 +56,7 @@ pub fn expand_deriving_clone(
                 }
             }
             ItemKind::Union(..) => {
-                bounds = vec![Literal(path_std!(cx, marker::Copy))];
+                bounds = vec![Literal(path_std!(marker::Copy))];
                 is_shallow = true;
                 substructure = combine_substructure(Box::new(|c, s, sub| {
                     cs_clone_shallow("Clone", c, s, sub, true)
@@ -78,14 +78,14 @@ pub fn expand_deriving_clone(
     let trait_def = TraitDef {
         span,
         attributes: Vec::new(),
-        path: path_std!(cx, clone::Clone),
+        path: path_std!(clone::Clone),
         additional_bounds: bounds,
-        generics: LifetimeBounds::empty(),
+        generics: Bounds::empty(),
         is_unsafe: false,
         supports_unions: true,
         methods: vec![MethodDef {
             name: sym::clone,
-            generics: LifetimeBounds::empty(),
+            generics: Bounds::empty(),
             explicit_self: borrowed_explicit_self(),
             args: Vec::new(),
             ret_ty: Self_,

src/librustc_builtin_macros/deriving/cmp/eq.rs

@@ -22,14 +22,14 @@ pub fn expand_deriving_eq(
     let trait_def = TraitDef {
         span,
         attributes: Vec::new(),
-        path: path_std!(cx, cmp::Eq),
+        path: path_std!(cmp::Eq),
         additional_bounds: Vec::new(),
-        generics: LifetimeBounds::empty(),
+        generics: Bounds::empty(),
         is_unsafe: false,
         supports_unions: true,
         methods: vec![MethodDef {
             name: sym::assert_receiver_is_total_eq,
-            generics: LifetimeBounds::empty(),
+            generics: Bounds::empty(),
             explicit_self: borrowed_explicit_self(),
             args: vec![],
             ret_ty: nil_ty(),
@@ -43,13 +43,7 @@ pub fn expand_deriving_eq(
         associated_types: Vec::new(),
     };
 
-    super::inject_impl_of_structural_trait(
-        cx,
-        span,
-        item,
-        path_std!(cx, marker::StructuralEq),
-        push,
-    );
+    super::inject_impl_of_structural_trait(cx, span, item, path_std!(marker::StructuralEq), push);
 
     trait_def.expand_ext(cx, mitem, item, push, true)
 }

src/librustc_builtin_macros/deriving/cmp/ord.rs

@@ -20,17 +20,17 @@ pub fn expand_deriving_ord(
     let trait_def = TraitDef {
         span,
         attributes: Vec::new(),
-        path: path_std!(cx, cmp::Ord),
+        path: path_std!(cmp::Ord),
         additional_bounds: Vec::new(),
-        generics: LifetimeBounds::empty(),
+        generics: Bounds::empty(),
         is_unsafe: false,
         supports_unions: false,
         methods: vec![MethodDef {
             name: sym::cmp,
-            generics: LifetimeBounds::empty(),
+            generics: Bounds::empty(),
             explicit_self: borrowed_explicit_self(),
-            args: vec![(borrowed_self(), "other")],
-            ret_ty: Literal(path_std!(cx, cmp::Ordering)),
+            args: vec![(borrowed_self(), sym::other)],
+            ret_ty: Literal(path_std!(cmp::Ordering)),
             attributes: attrs,
             is_unsafe: false,
             unify_fieldless_variants: true,

src/librustc_builtin_macros/deriving/cmp/partial_eq.rs

@@ -69,9 +69,9 @@ pub fn expand_deriving_partial_eq(
             let attrs = vec![cx.attribute(inline)];
             MethodDef {
                 name: $name,
-                generics: LifetimeBounds::empty(),
+                generics: Bounds::empty(),
                 explicit_self: borrowed_explicit_self(),
-                args: vec![(borrowed_self(), "other")],
+                args: vec![(borrowed_self(), sym::other)],
                 ret_ty: Literal(path_local!(bool)),
                 attributes: attrs,
                 is_unsafe: false,
@@ -85,7 +85,7 @@ pub fn expand_deriving_partial_eq(
         cx,
         span,
         item,
-        path_std!(cx, marker::StructuralPartialEq),
+        path_std!(marker::StructuralPartialEq),
         push,
     );
 
@@ -100,9 +100,9 @@ pub fn expand_deriving_partial_eq(
     let trait_def = TraitDef {
         span,
         attributes: Vec::new(),
-        path: path_std!(cx, cmp::PartialEq),
+        path: path_std!(cmp::PartialEq),
         additional_bounds: Vec::new(),
-        generics: LifetimeBounds::empty(),
+        generics: Bounds::empty(),
         is_unsafe: false,
         supports_unions: false,
         methods,

src/librustc_builtin_macros/deriving/cmp/partial_ord.rs

@@ -23,9 +23,9 @@ pub fn expand_deriving_partial_ord(
             let attrs = vec![cx.attribute(inline)];
             MethodDef {
                 name: $name,
-                generics: LifetimeBounds::empty(),
+                generics: Bounds::empty(),
                 explicit_self: borrowed_explicit_self(),
-                args: vec![(borrowed_self(), "other")],
+                args: vec![(borrowed_self(), sym::other)],
                 ret_ty: Literal(path_local!(bool)),
                 attributes: attrs,
                 is_unsafe: false,
@@ -37,9 +37,9 @@ pub fn expand_deriving_partial_ord(
         }};
     }
 
-    let ordering_ty = Literal(path_std!(cx, cmp::Ordering));
+    let ordering_ty = Literal(path_std!(cmp::Ordering));
     let ret_ty = Literal(Path::new_(
-        pathvec_std!(cx, option::Option),
+        pathvec_std!(option::Option),
         None,
         vec![Box::new(ordering_ty)],
         PathKind::Std,
@@ -50,9 +50,9 @@ pub fn expand_deriving_partial_ord(
 
     let partial_cmp_def = MethodDef {
         name: sym::partial_cmp,
-        generics: LifetimeBounds::empty(),
+        generics: Bounds::empty(),
         explicit_self: borrowed_explicit_self(),
-        args: vec![(borrowed_self(), "other")],
+        args: vec![(borrowed_self(), sym::other)],
         ret_ty,
         attributes: attrs,
         is_unsafe: false,
@@ -80,9 +80,9 @@ pub fn expand_deriving_partial_ord(
     let trait_def = TraitDef {
         span,
         attributes: vec![],
-        path: path_std!(cx, cmp::PartialOrd),
+        path: path_std!(cmp::PartialOrd),
         additional_bounds: vec![],
-        generics: LifetimeBounds::empty(),
+        generics: Bounds::empty(),
         is_unsafe: false,
         supports_unions: false,
         methods,

src/librustc_builtin_macros/deriving/debug.rs

@@ -18,22 +18,22 @@ pub fn expand_deriving_debug(
 ) {
     // &mut ::std::fmt::Formatter
     let fmtr =
-        Ptr(Box::new(Literal(path_std!(cx, fmt::Formatter))), Borrowed(None, ast::Mutability::Mut));
+        Ptr(Box::new(Literal(path_std!(fmt::Formatter))), Borrowed(None, ast::Mutability::Mut));
 
     let trait_def = TraitDef {
         span,
         attributes: Vec::new(),
-        path: path_std!(cx, fmt::Debug),
+        path: path_std!(fmt::Debug),
         additional_bounds: Vec::new(),
-        generics: LifetimeBounds::empty(),
+        generics: Bounds::empty(),
         is_unsafe: false,
         supports_unions: false,
         methods: vec![MethodDef {
             name: sym::fmt,
-            generics: LifetimeBounds::empty(),
+            generics: Bounds::empty(),
             explicit_self: borrowed_explicit_self(),
-            args: vec![(fmtr, "f")],
-            ret_ty: Literal(path_std!(cx, fmt::Result)),
+            args: vec![(fmtr, sym::f)],
+            ret_ty: Literal(path_std!(fmt::Result)),
             attributes: Vec::new(),
             is_unsafe: false,
             unify_fieldless_variants: false,
@@ -62,7 +62,7 @@ fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>
     // We want to make sure we have the ctxt set so that we can use unstable methods
     let span = cx.with_def_site_ctxt(span);
     let name = cx.expr_lit(span, ast::LitKind::Str(ident.name, ast::StrStyle::Cooked));
-    let builder = cx.ident_of("debug_trait_builder", span);
+    let builder = Ident::new(sym::debug_trait_builder, span);
     let builder_expr = cx.expr_ident(span, builder);
 
     let fmt = substr.nonself_args[0].clone();
@@ -71,7 +71,8 @@ fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>
     match vdata {
         ast::VariantData::Tuple(..) | ast::VariantData::Unit(..) => {
             // tuple struct/"normal" variant
-            let expr = cx.expr_method_call(span, fmt, cx.ident_of("debug_tuple", span), vec![name]);
+            let expr =
+                cx.expr_method_call(span, fmt, Ident::new(sym::debug_tuple, span), vec![name]);
             stmts.push(cx.stmt_let(span, true, builder, expr));
 
             for field in fields {
@@ -94,7 +95,7 @@ fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>
         ast::VariantData::Struct(..) => {
             // normal struct/struct variant
             let expr =
-                cx.expr_method_call(span, fmt, cx.ident_of("debug_struct", span), vec![name]);
+                cx.expr_method_call(span, fmt, Ident::new(sym::debug_struct, span), vec![name]);
             stmts.push(cx.stmt_let(DUMMY_SP, true, builder, expr));
 
             for field in fields {
@@ -117,7 +118,7 @@ fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>
         }
     }
 
-    let expr = cx.expr_method_call(span, builder_expr, cx.ident_of("finish", span), vec![]);
+    let expr = cx.expr_method_call(span, builder_expr, Ident::new(sym::finish, span), vec![]);
 
     stmts.push(cx.stmt_expr(expr));
     let block = cx.block(span, stmts);

src/librustc_builtin_macros/deriving/decodable.rs

@@ -8,7 +8,7 @@ use rustc_ast::ast;
 use rustc_ast::ast::{Expr, MetaItem, Mutability};
 use rustc_ast::ptr::P;
 use rustc_expand::base::{Annotatable, ExtCtxt};
-use rustc_span::symbol::{sym, Symbol};
+use rustc_span::symbol::{sym, Ident, Symbol};
 use rustc_span::Span;
 
 pub fn expand_deriving_rustc_decodable(
@@ -18,38 +18,37 @@ pub fn expand_deriving_rustc_decodable(
     item: &Annotatable,
     push: &mut dyn FnMut(Annotatable),
 ) {
-    let krate = "rustc_serialize";
-    let typaram = "__D";
+    let krate = sym::rustc_serialize;
+    let typaram = sym::__D;
 
     let trait_def = TraitDef {
         span,
         attributes: Vec::new(),
-        path: Path::new_(vec![krate, "Decodable"], None, vec![], PathKind::Global),
+        path: Path::new_(vec![krate, sym::Decodable], None, vec![], PathKind::Global),
         additional_bounds: Vec::new(),
-        generics: LifetimeBounds::empty(),
+        generics: Bounds::empty(),
         is_unsafe: false,
         supports_unions: false,
         methods: vec![MethodDef {
             name: sym::decode,
-            generics: LifetimeBounds {
-                lifetimes: Vec::new(),
+            generics: Bounds {
                 bounds: vec![(
                     typaram,
-                    vec![Path::new_(vec![krate, "Decoder"], None, vec![], PathKind::Global)],
+                    vec![Path::new_(vec![krate, sym::Decoder], None, vec![], PathKind::Global)],
                 )],
             },
             explicit_self: None,
             args: vec![(
                 Ptr(Box::new(Literal(Path::new_local(typaram))), Borrowed(None, Mutability::Mut)),
-                "d",
+                sym::d,
             )],
             ret_ty: Literal(Path::new_(
-                pathvec_std!(cx, result::Result),
+                pathvec_std!(result::Result),
                 None,
                 vec![
                     Box::new(Self_),
                     Box::new(Literal(Path::new_(
-                        vec![typaram, "Error"],
+                        vec![typaram, sym::Error],
                         None,
                         vec![],
                         PathKind::Local,
@@ -74,17 +73,17 @@ fn decodable_substructure(
     cx: &mut ExtCtxt<'_>,
     trait_span: Span,
     substr: &Substructure<'_>,
-    krate: &str,
+    krate: Symbol,
 ) -> P<Expr> {
     let decoder = substr.nonself_args[0].clone();
     let recurse = vec![
-        cx.ident_of(krate, trait_span),
-        cx.ident_of("Decodable", trait_span),
-        cx.ident_of("decode", trait_span),
+        Ident::new(krate, trait_span),
+        Ident::new(sym::Decodable, trait_span),
+        Ident::new(sym::decode, trait_span),
     ];
     let exprdecode = cx.expr_path(cx.path_global(trait_span, recurse));
     // throw an underscore in front to suppress unused variable warnings
-    let blkarg = cx.ident_of("_d", trait_span);
+    let blkarg = Ident::new(sym::_d, trait_span);
     let blkdecoder = cx.expr_ident(trait_span, blkarg);
 
     match *substr.fields {
@@ -93,7 +92,7 @@ fn decodable_substructure(
                 Unnamed(ref fields, _) => fields.len(),
                 Named(ref fields) => fields.len(),
             };
-            let read_struct_field = cx.ident_of("read_struct_field", trait_span);
+            let read_struct_field = Ident::new(sym::read_struct_field, trait_span);
 
             let path = cx.path_ident(trait_span, substr.type_ident);
             let result =
@@ -116,7 +115,7 @@ fn decodable_substructure(
             cx.expr_method_call(
                 trait_span,
                 decoder,
-                cx.ident_of("read_struct", trait_span),
+                Ident::new(sym::read_struct, trait_span),
                 vec![
                     cx.expr_str(trait_span, substr.type_ident.name),
                     cx.expr_usize(trait_span, nfields),
@@ -125,11 +124,11 @@ fn decodable_substructure(
             )
         }
         StaticEnum(_, ref fields) => {
-            let variant = cx.ident_of("i", trait_span);
+            let variant = Ident::new(sym::i, trait_span);
 
             let mut arms = Vec::with_capacity(fields.len() + 1);
             let mut variants = Vec::with_capacity(fields.len());
-            let rvariant_arg = cx.ident_of("read_enum_variant_arg", trait_span);
+            let rvariant_arg = Ident::new(sym::read_enum_variant_arg, trait_span);
 
             for (i, &(ident, v_span, ref parts)) in fields.iter().enumerate() {
                 variants.push(cx.expr_str(v_span, ident.name));
@@ -164,13 +163,13 @@ fn decodable_substructure(
             let result = cx.expr_method_call(
                 trait_span,
                 blkdecoder,
-                cx.ident_of("read_enum_variant", trait_span),
+                Ident::new(sym::read_enum_variant, trait_span),
                 vec![variant_vec, lambda],
             );
             cx.expr_method_call(
                 trait_span,
                 decoder,
-                cx.ident_of("read_enum", trait_span),
+                Ident::new(sym::read_enum, trait_span),
                 vec![
                     cx.expr_str(trait_span, substr.type_ident.name),
                     cx.lambda1(trait_span, result, blkarg),

src/librustc_builtin_macros/deriving/default.rs

@@ -1,6 +1,5 @@
 use crate::deriving::generic::ty::*;
 use crate::deriving::generic::*;
-use crate::deriving::path_std;
 
 use rustc_ast::ast::{Expr, MetaItem};
 use rustc_ast::ptr::P;
@@ -21,14 +20,14 @@ pub fn expand_deriving_default(
     let trait_def = TraitDef {
         span,
         attributes: Vec::new(),
-        path: path_std!(cx, default::Default),
+        path: Path::new(vec![kw::Default, sym::Default]),
         additional_bounds: Vec::new(),
-        generics: LifetimeBounds::empty(),
+        generics: Bounds::empty(),
         is_unsafe: false,
         supports_unions: false,
         methods: vec![MethodDef {
             name: kw::Default,
-            generics: LifetimeBounds::empty(),
+            generics: Bounds::empty(),
             explicit_self: None,
             args: Vec::new(),
             ret_ty: Self_,