Pass symbols to `ExtCtxt::std_path` instead of strings.

Because this function is hot.

Also remove the dead `ty_option` function.

9 files changed, 34 insertions, 31 deletions

diff --git a/src/libsyntax_ext/deriving/clone.rs b/src/libsyntax_ext/deriving/clone.rs
index 417dd2525d6..b3b6328e2ca 100644
--- a/src/libsyntax_ext/deriving/clone.rs
+++ b/src/libsyntax_ext/deriving/clone.rs
@@ -7,7 +7,7 @@ use syntax::attr;
 use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax::ext::build::AstBuilder;
 use syntax::ptr::P;
-use syntax::symbol::{kw, sym};
+use syntax::symbol::{kw, sym, Symbol};
 use syntax_pos::Span;
 
 pub fn expand_deriving_clone(cx: &mut ExtCtxt<'_>,
@@ -115,7 +115,7 @@ fn cs_clone_shallow(name: &str,
         // set the expn ID so we can use the unstable struct.
         let span = span.with_ctxt(cx.backtrace());
         let assert_path = cx.path_all(span, true,
-                                        cx.std_path(&["clone", helper_name]),
+                                        cx.std_path(&[sym::clone, Symbol::intern(helper_name)]),
                                         vec![GenericArg::Type(ty)], vec![]);
         stmts.push(cx.stmt_let_type_only(span, cx.ty_path(assert_path)));
     }
@@ -157,7 +157,7 @@ fn cs_clone(name: &str,
             -> P<Expr> {
     let ctor_path;
     let all_fields;
-    let fn_path = cx.std_path(&["clone", "Clone", "clone"]);
+    let fn_path = cx.std_path(&[sym::clone, sym::Clone, sym::clone]);
     let subcall = |cx: &mut ExtCtxt<'_>, field: &FieldInfo<'_>| {
         let args = vec![cx.expr_addr_of(field.span, field.self_.clone())];
         cx.expr_call_global(field.span, fn_path.clone(), args)
diff --git a/src/libsyntax_ext/deriving/cmp/eq.rs b/src/libsyntax_ext/deriving/cmp/eq.rs
index e7d7f136e18..1d981e0ff79 100644
--- a/src/libsyntax_ext/deriving/cmp/eq.rs
+++ b/src/libsyntax_ext/deriving/cmp/eq.rs
@@ -6,7 +6,7 @@ use syntax::ast::{self, Expr, MetaItem, GenericArg};
 use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax::ext::build::AstBuilder;
 use syntax::ptr::P;
-use syntax::symbol::sym;
+use syntax::symbol::{sym, Symbol};
 use syntax_pos::Span;
 
 pub fn expand_deriving_eq(cx: &mut ExtCtxt<'_>,
@@ -54,7 +54,7 @@ fn cs_total_eq_assert(cx: &mut ExtCtxt<'_>,
         // set the expn ID so we can use the unstable struct.
         let span = span.with_ctxt(cx.backtrace());
         let assert_path = cx.path_all(span, true,
-                                        cx.std_path(&["cmp", helper_name]),
+                                        cx.std_path(&[sym::cmp, Symbol::intern(helper_name)]),
                                         vec![GenericArg::Type(ty)], vec![]);
         stmts.push(cx.stmt_let_type_only(span, cx.ty_path(assert_path)));
     }
diff --git a/src/libsyntax_ext/deriving/cmp/ord.rs b/src/libsyntax_ext/deriving/cmp/ord.rs
index 282cfa5a4bf..b25a9e4c50f 100644
--- a/src/libsyntax_ext/deriving/cmp/ord.rs
+++ b/src/libsyntax_ext/deriving/cmp/ord.rs
@@ -55,9 +55,9 @@ pub fn ordering_collapsed(cx: &mut ExtCtxt<'_>,
 
 pub fn cs_cmp(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) -> P<Expr> {
     let test_id = cx.ident_of("cmp").gensym();
-    let equals_path = cx.path_global(span, cx.std_path(&["cmp", "Ordering", "Equal"]));
+    let equals_path = cx.path_global(span, cx.std_path(&[sym::cmp, sym::Ordering, sym::Equal]));
 
-    let cmp_path = cx.std_path(&["cmp", "Ord", "cmp"]);
+    let cmp_path = cx.std_path(&[sym::cmp, sym::Ord, sym::cmp]);
 
     // Builds:
     //
diff --git a/src/libsyntax_ext/deriving/cmp/partial_ord.rs b/src/libsyntax_ext/deriving/cmp/partial_ord.rs
index abfa79c2b4d..3980741f252 100644
--- a/src/libsyntax_ext/deriving/cmp/partial_ord.rs
+++ b/src/libsyntax_ext/deriving/cmp/partial_ord.rs
@@ -8,7 +8,7 @@ use syntax::ast::{self, BinOpKind, Expr, MetaItem};
 use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax::ext::build::AstBuilder;
 use syntax::ptr::P;
-use syntax::symbol::sym;
+use syntax::symbol::{sym, Symbol};
 use syntax_pos::Span;
 
 pub fn expand_deriving_partial_ord(cx: &mut ExtCtxt<'_>,
@@ -114,11 +114,11 @@ pub fn some_ordering_collapsed(cx: &mut ExtCtxt<'_>,
 
 pub fn cs_partial_cmp(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) -> P<Expr> {
     let test_id = cx.ident_of("cmp").gensym();
-    let ordering = cx.path_global(span, cx.std_path(&["cmp", "Ordering", "Equal"]));
+    let ordering = cx.path_global(span, cx.std_path(&[sym::cmp, sym::Ordering, sym::Equal]));
     let ordering_expr = cx.expr_path(ordering.clone());
     let equals_expr = cx.expr_some(span, ordering_expr);
 
-    let partial_cmp_path = cx.std_path(&["cmp", "PartialOrd", "partial_cmp"]);
+    let partial_cmp_path = cx.std_path(&[sym::cmp, sym::PartialOrd, sym::partial_cmp]);
 
     // Builds:
     //
@@ -188,7 +188,8 @@ fn cs_op(less: bool,
          span: Span,
          substr: &Substructure<'_>) -> P<Expr> {
     let ordering_path = |cx: &mut ExtCtxt<'_>, name: &str| {
-        cx.expr_path(cx.path_global(span, cx.std_path(&["cmp", "Ordering", name])))
+        cx.expr_path(cx.path_global(
+            span, cx.std_path(&[sym::cmp, sym::Ordering, Symbol::intern(name)])))
     };
 
     let par_cmp = |cx: &mut ExtCtxt<'_>, span, self_f: P<Expr>, other_fs: &[P<Expr>], default| {
@@ -198,9 +199,9 @@ fn cs_op(less: bool,
         };
 
         // `PartialOrd::partial_cmp(self.fi, other.fi)`
-        let cmp_path = cx.expr_path(cx.path_global(span, cx.std_path(&["cmp",
-                                                                       "PartialOrd",
-                                                                       "partial_cmp"])));
+        let cmp_path = cx.expr_path(cx.path_global(span, cx.std_path(&[sym::cmp,
+                                                                       sym::PartialOrd,
+                                                                       sym::partial_cmp])));
         let cmp = cx.expr_call(span,
                                cmp_path,
                                vec![cx.expr_addr_of(span, self_f),
@@ -208,9 +209,9 @@ fn cs_op(less: bool,
 
         let default = ordering_path(cx, default);
         // `Option::unwrap_or(_, Ordering::Equal)`
-        let unwrap_path = cx.expr_path(cx.path_global(span, cx.std_path(&["option",
-                                                                          "Option",
-                                                                          "unwrap_or"])));
+        let unwrap_path = cx.expr_path(cx.path_global(span, cx.std_path(&[sym::option,
+                                                                          sym::Option,
+                                                                          sym::unwrap_or])));
         cx.expr_call(span, unwrap_path, vec![cmp, default])
     };
 
@@ -256,9 +257,9 @@ fn cs_op(less: bool,
 
             // `Ordering::then_with(Option::unwrap_or(..), ..)`
             let then_with_path = cx.expr_path(cx.path_global(span,
-                                                             cx.std_path(&["cmp",
-                                                                           "Ordering",
-                                                                           "then_with"])));
+                                                             cx.std_path(&[sym::cmp,
+                                                                           sym::Ordering,
+                                                                           sym::then_with])));
             cx.expr_call(span, then_with_path, vec![par_cmp, cx.lambda0(span, subexpr)])
         },
         |cx, args| {
diff --git a/src/libsyntax_ext/deriving/default.rs b/src/libsyntax_ext/deriving/default.rs
index b42dde16420..fd8e87e2fef 100644
--- a/src/libsyntax_ext/deriving/default.rs
+++ b/src/libsyntax_ext/deriving/default.rs
@@ -6,7 +6,7 @@ use syntax::ast::{Expr, MetaItem};
 use syntax::ext::base::{Annotatable, DummyResult, ExtCtxt};
 use syntax::ext::build::AstBuilder;
 use syntax::ptr::P;
-use syntax::symbol::sym;
+use syntax::symbol::{kw, sym};
 use syntax::span_err;
 use syntax_pos::Span;
 
@@ -47,7 +47,8 @@ fn default_substructure(cx: &mut ExtCtxt<'_>,
                         trait_span: Span,
                         substr: &Substructure<'_>)
                         -> P<Expr> {
-    let default_ident = cx.std_path(&["default", "Default", "default"]);
+    // Note that `kw::Default` is "default" and `sym::Default` is "Default"!
+    let default_ident = cx.std_path(&[kw::Default, sym::Default, kw::Default]);
     let default_call = |span| cx.expr_call_global(span, default_ident.clone(), Vec::new());
 
     return match *substr.fields {
diff --git a/src/libsyntax_ext/deriving/hash.rs b/src/libsyntax_ext/deriving/hash.rs
index 0d4f2ddc3be..e7f99d45782 100644
--- a/src/libsyntax_ext/deriving/hash.rs
+++ b/src/libsyntax_ext/deriving/hash.rs
@@ -6,6 +6,7 @@ use syntax::ast::{Expr, MetaItem, Mutability};
 use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax::ext::build::AstBuilder;
 use syntax::ptr::P;
+use syntax::symbol::sym;
 use syntax_pos::Span;
 
 pub fn expand_deriving_hash(cx: &mut ExtCtxt<'_>,
@@ -60,7 +61,7 @@ fn hash_substructure(cx: &mut ExtCtxt<'_>, trait_span: Span, substr: &Substructu
     };
     let call_hash = |span, thing_expr| {
         let hash_path = {
-            let strs = cx.std_path(&["hash", "Hash", "hash"]);
+            let strs = cx.std_path(&[sym::hash, sym::Hash, sym::hash]);
 
             cx.expr_path(cx.path_global(span, strs))
         };
diff --git a/src/libsyntax_ext/deriving/mod.rs b/src/libsyntax_ext/deriving/mod.rs
index eff71bc969e..ac41f30e6b3 100644
--- a/src/libsyntax_ext/deriving/mod.rs
+++ b/src/libsyntax_ext/deriving/mod.rs
@@ -150,7 +150,7 @@ fn call_intrinsic(cx: &ExtCtxt<'_>,
         mark.set_expn_info(info);
         span = span.with_ctxt(SyntaxContext::empty().apply_mark(mark));
     }
-    let path = cx.std_path(&["intrinsics", intrinsic]);
+    let path = cx.std_path(&[sym::intrinsics, Symbol::intern(intrinsic)]);
     let call = cx.expr_call_global(span, path, args);
 
     cx.expr_block(P(ast::Block {
diff --git a/src/libsyntax_ext/env.rs b/src/libsyntax_ext/env.rs
index 72a66ae3845..b7f2ecf0f91 100644
--- a/src/libsyntax_ext/env.rs
+++ b/src/libsyntax_ext/env.rs
@@ -27,7 +27,7 @@ pub fn expand_option_env<'cx>(cx: &'cx mut ExtCtxt<'_>,
             let lt = cx.lifetime(sp, Ident::with_empty_ctxt(kw::StaticLifetime));
             cx.expr_path(cx.path_all(sp,
                                      true,
-                                     cx.std_path(&["option", "Option", "None"]),
+                                     cx.std_path(&[sym::option, sym::Option, sym::None]),
                                      vec![GenericArg::Type(cx.ty_rptr(sp,
                                                      cx.ty_ident(sp,
                                                                  Ident::with_empty_ctxt(sym::str)),
@@ -37,7 +37,7 @@ pub fn expand_option_env<'cx>(cx: &'cx mut ExtCtxt<'_>,
         }
         Ok(s) => {
             cx.expr_call_global(sp,
-                                cx.std_path(&["option", "Option", "Some"]),
+                                cx.std_path(&[sym::option, sym::Option, sym::Some]),
                                 vec![cx.expr_str(sp, Symbol::intern(&s))])
         }
     };
diff --git a/src/libsyntax_ext/format.rs b/src/libsyntax_ext/format.rs
index 9e54c0634b6..b5be45547cf 100644
--- a/src/libsyntax_ext/format.rs
+++ b/src/libsyntax_ext/format.rs
@@ -387,7 +387,7 @@ impl<'a, 'b> Context<'a, 'b> {
     }
 
     fn rtpath(ecx: &ExtCtxt<'_>, s: &str) -> Vec<ast::Ident> {
-        ecx.std_path(&["fmt", "rt", "v1", s])
+        ecx.std_path(&[sym::fmt, sym::rt, sym::v1, Symbol::intern(s)])
     }
 
     fn build_count(&self, c: parse::Count<'_>) -> P<ast::Expr> {
@@ -644,7 +644,7 @@ impl<'a, 'b> Context<'a, 'b> {
             ("new_v1_formatted", vec![pieces, args_slice, fmt])
         };
 
-        let path = self.ecx.std_path(&["fmt", "Arguments", fn_name]);
+        let path = self.ecx.std_path(&[sym::fmt, sym::Arguments, Symbol::intern(fn_name)]);
         self.ecx.expr_call_global(self.macsp, path, fn_args)
     }
 
@@ -675,14 +675,14 @@ impl<'a, 'b> Context<'a, 'b> {
                 }
             }
             Count => {
-                let path = ecx.std_path(&["fmt", "ArgumentV1", "from_usize"]);
+                let path = ecx.std_path(&[sym::fmt, sym::ArgumentV1, sym::from_usize]);
                 return ecx.expr_call_global(macsp, path, vec![arg]);
             }
         };
 
-        let path = ecx.std_path(&["fmt", trait_, "fmt"]);
+        let path = ecx.std_path(&[sym::fmt, Symbol::intern(trait_), sym::fmt]);
         let format_fn = ecx.path_global(sp, path);
-        let path = ecx.std_path(&["fmt", "ArgumentV1", "new"]);
+        let path = ecx.std_path(&[sym::fmt, sym::ArgumentV1, sym::new]);
         ecx.expr_call_global(macsp, path, vec![arg, ecx.expr_path(format_fn)])
     }
 }