Rollup merge of #64670 - Mark-Simulacrum:ext-build-simplify, r=petrochenkov

Cleanup syntax::ext::build

I suspect most of this code could be inlined but I only removed the bits where the inlining didn't really hurt readability (i.e., method call -> function call) or the completely unused code.

src/libsyntax_ext/deriving/clone.rs

@@ -115,7 +115,7 @@ fn cs_clone_shallow(name: &str,
         let span = cx.with_def_site_ctxt(span);
         let assert_path = cx.path_all(span, true,
                                         cx.std_path(&[sym::clone, Symbol::intern(helper_name)]),
-                                        vec![GenericArg::Type(ty)], vec![]);
+                                        vec![GenericArg::Type(ty)]);
         stmts.push(cx.stmt_let_type_only(span, cx.ty_path(assert_path)));
     }
     fn process_variant(cx: &mut ExtCtxt<'_>, stmts: &mut Vec<ast::Stmt>, variant: &VariantData) {

src/libsyntax_ext/deriving/cmp/eq.rs

@@ -2,7 +2,7 @@ use crate::deriving::path_std;
 use crate::deriving::generic::*;
 use crate::deriving::generic::ty::*;
 
-use syntax::ast::{self, Expr, MetaItem, GenericArg};
+use syntax::ast::{self, Ident, Expr, MetaItem, GenericArg};
 use syntax::ext::base::{Annotatable, ExtCtxt, SpecialDerives};
 use syntax::ptr::P;
 use syntax::symbol::{sym, Symbol};
@@ -16,8 +16,8 @@ pub fn expand_deriving_eq(cx: &mut ExtCtxt<'_>,
     cx.resolver.add_derives(cx.current_expansion.id.expn_data().parent, SpecialDerives::EQ);
 
     let inline = cx.meta_word(span, sym::inline);
-    let hidden = cx.meta_list_item_word(span, sym::hidden);
-    let doc = cx.meta_list(span, sym::doc, vec![hidden]);
+    let hidden = syntax::attr::mk_nested_word_item(Ident::new(sym::hidden, span));
+    let doc = syntax::attr::mk_list_item(Ident::new(sym::doc, span), vec![hidden]);
     let attrs = vec![cx.attribute(inline), cx.attribute(doc)];
     let trait_def = TraitDef {
         span,
@@ -56,7 +56,7 @@ fn cs_total_eq_assert(cx: &mut ExtCtxt<'_>,
         let span = cx.with_def_site_ctxt(span);
         let assert_path = cx.path_all(span, true,
                                         cx.std_path(&[sym::cmp, Symbol::intern(helper_name)]),
-                                        vec![GenericArg::Type(ty)], vec![]);
+                                        vec![GenericArg::Type(ty)]);
         stmts.push(cx.stmt_let_type_only(span, cx.ty_path(assert_path)));
     }
     fn process_variant(cx: &mut ExtCtxt<'_>,

src/libsyntax_ext/deriving/generic/mod.rs

@@ -664,7 +664,7 @@ impl<'a> TraitDef<'a> {
         }).collect();
 
         // Create the type of `self`.
-        let path = cx.path_all(self.span, false, vec![type_ident], self_params, vec![]);
+        let path = cx.path_all(self.span, false, vec![type_ident], self_params);
         let self_type = cx.ty_path(path);
 
         let attr = cx.attribute(cx.meta_word(self.span, sym::automatically_derived));
@@ -672,8 +672,11 @@ impl<'a> TraitDef<'a> {
         attr::mark_used(&attr);
         let opt_trait_ref = Some(trait_ref);
         let unused_qual = {
-            let word = cx.meta_list_item_word(self.span, Symbol::intern("unused_qualifications"));
-            cx.attribute(cx.meta_list(self.span, sym::allow, vec![word]))
+            let word = syntax::attr::mk_nested_word_item(
+                Ident::new(Symbol::intern("unused_qualifications"), self.span));
+            let list = syntax::attr::mk_list_item(
+                Ident::new(sym::allow, self.span), vec![word]);
+            cx.attribute(list)
         };
 
         let mut a = vec![attr, unused_qual];

src/libsyntax_ext/deriving/generic/ty.rs

@@ -82,12 +82,12 @@ impl<'a> Path<'a> {
                        .collect();
 
         match self.kind {
-            PathKind::Global => cx.path_all(span, true, idents, params, Vec::new()),
-            PathKind::Local => cx.path_all(span, false, idents, params, Vec::new()),
+            PathKind::Global => cx.path_all(span, true, idents, params),
+            PathKind::Local => cx.path_all(span, false, idents, params),
             PathKind::Std => {
                 let def_site = cx.with_def_site_ctxt(DUMMY_SP);
                 idents.insert(0, Ident::new(kw::DollarCrate, def_site));
-                cx.path_all(span, false, idents, params, Vec::new())
+                cx.path_all(span, false, idents, params)
             }
         }
 
@@ -183,7 +183,7 @@ impl<'a> Ty<'a> {
                     }
                 }).collect();
 
-                cx.path_all(span, false, vec![self_ty], params, vec![])
+                cx.path_all(span, false, vec![self_ty], params)
             }
             Literal(ref p) => p.to_path(cx, span, self_ty, generics),
             Ptr(..) => cx.span_bug(span, "pointer in a path in generic `derive`"),

src/libsyntax_ext/env.rs

@@ -32,7 +32,7 @@ pub fn expand_option_env<'cx>(cx: &'cx mut ExtCtxt<'_>,
                                                                  Ident::new(sym::str, sp)),
                                                      Some(lt),
                                                      ast::Mutability::Immutable))],
-                                     vec![]))
+                                     ))
         }
         Ok(s) => {
             cx.expr_call_global(sp,

src/libsyntax_ext/test.rs

@@ -145,8 +145,8 @@ pub fn expand_test_or_bench(
     let mut test_const = cx.item(sp, ast::Ident::new(item.ident.name, sp),
         vec![
             // #[cfg(test)]
-            cx.attribute(cx.meta_list(attr_sp, sym::cfg, vec![
-                cx.meta_list_item_word(attr_sp, sym::test)
+            cx.attribute(attr::mk_list_item(ast::Ident::new(sym::cfg, attr_sp), vec![
+                attr::mk_nested_word_item(ast::Ident::new(sym::test, attr_sp))
             ])),
             // #[rustc_test_marker]
             cx.attribute(cx.meta_word(attr_sp, sym::rustc_test_marker)),