auto merge of #5296 : nikomatsakis/rust/region-syntax-expl-lifetimes-2, r=nikomatsakis

Modify pretty-printer to emit lifetimes and fix a few minor
parser bugs that this uncovered.

r? whomever.

Author: bors

src/librustc/middle/region.rs

@@ -31,6 +31,7 @@ use std::oldmap::HashMap;
 use syntax::ast_map;
 use syntax::codemap::span;
 use syntax::print::pprust;
+use syntax::parse::token::special_idents;
 use syntax::{ast, visit};
 
 pub type parent = Option<ast::node_id>;
@@ -546,29 +547,20 @@ pub impl DetermineRpCtxt {
     // with &self type, &self is also bound.  We detect those last two
     // cases via flags (anon_implies_rp and self_implies_rp) that are
     // true when the anon or self region implies RP.
-    fn region_is_relevant(&self, r: @ast::region) -> bool {
-        match r.node {
-            ast::re_static => false,
-            ast::re_anon => self.anon_implies_rp,
-            ast::re_self => self.self_implies_rp,
-            ast::re_named(_) => false
-        }
-    }
-
-    // For named types like Foo, if there is no explicit region
-    // parameter, then we will add the anonymous region, so there is
-    // a dependency if the anonymous region implies rp.
-    //
-    // If the region is explicitly specified, then we follows the
-    // normal rules.
-    fn opt_region_is_relevant(&self,
-                              opt_r: Option<@ast::region>)
-                           -> bool {
-        debug!("opt_region_is_relevant: %? (anon_implies_rp=%b)",
-               opt_r, self.anon_implies_rp);
-        match opt_r {
-          None => self.anon_implies_rp,
-          Some(r) => self.region_is_relevant(r)
+    fn region_is_relevant(&self, r: Option<@ast::Lifetime>) -> bool {
+        match r {
+            None => {
+                self.anon_implies_rp
+            }
+            Some(ref l) if l.ident == special_idents::static => {
+                false
+            }
+            Some(ref l) if l.ident == special_idents::self_ => {
+                self.self_implies_rp
+            }
+            Some(_) => {
+                false
+            }
         }
     }
 
@@ -672,8 +664,8 @@ pub fn determine_rp_in_ty(ty: @ast::Ty,
             debug!("referenced fn type: %s",
                    pprust::ty_to_str(ty, sess.intr()));
             match f.region {
-                Some(r) => {
-                    if cx.region_is_relevant(r) {
+                Some(_) => {
+                    if cx.region_is_relevant(f.region) {
                         cx.add_rp(cx.item_id,
                                   cx.add_variance(rv_contravariant))
                     }
@@ -699,7 +691,7 @@ pub fn determine_rp_in_ty(ty: @ast::Ty,
         match cx.def_map.find(&id) {
           Some(ast::def_ty(did)) | Some(ast::def_struct(did)) => {
             if did.crate == ast::local_crate {
-                if cx.opt_region_is_relevant(path.rp) {
+                if cx.region_is_relevant(path.rp) {
                     cx.add_dep(did.node);
                 }
             } else {
@@ -709,7 +701,7 @@ pub fn determine_rp_in_ty(ty: @ast::Ty,
                   Some(variance) => {
                     debug!("reference to external, rp'd type %s",
                            pprust::ty_to_str(ty, sess.intr()));
-                    if cx.opt_region_is_relevant(path.rp) {
+                    if cx.region_is_relevant(path.rp) {
                         cx.add_rp(cx.item_id, cx.add_variance(variance))
                     }
                   }

src/librustc/middle/typeck/astconv.rs

@@ -65,7 +65,8 @@ use core::result;
 use core::vec;
 use syntax::ast;
 use syntax::codemap::span;
-use syntax::print::pprust::{region_to_str, path_to_str};
+use syntax::print::pprust::{lifetime_to_str, path_to_str};
+use syntax::parse::token::special_idents;
 use util::common::indenter;
 
 pub trait AstConv {
@@ -79,21 +80,16 @@ pub trait AstConv {
 pub fn get_region_reporting_err(
     tcx: ty::ctxt,
     span: span,
-    a_r: Option<@ast::region>,
+    a_r: Option<@ast::Lifetime>,
     res: Result<ty::Region, RegionError>) -> ty::Region
 {
     match res {
         result::Ok(r) => r,
         result::Err(ref e) => {
             let descr = match a_r {
                 None => ~"anonymous lifetime",
-                Some(a) if a.node == ast::re_anon => {
-                    ~"anonymous lifetime"
-                }
-                Some(a) => {
-                    fmt!("lifetime %s",
-                         region_to_str(a, tcx.sess.intr()))
-                }
+                Some(a) => fmt!("lifetime %s",
+                                lifetime_to_str(a, tcx.sess.intr()))
             };
             tcx.sess.span_err(
                 span,
@@ -105,19 +101,28 @@ pub fn get_region_reporting_err(
 }
 
 pub fn ast_region_to_region<AC:AstConv,RS:region_scope + Copy + Durable>(
-        self: &AC,
-        rscope: &RS,
-        span: span,
-        a_r: @ast::region)
-     -> ty::Region {
-    let res = match a_r.node {
-        ast::re_static => Ok(ty::re_static),
-        ast::re_anon => rscope.anon_region(span),
-        ast::re_self => rscope.self_region(span),
-        ast::re_named(id) => rscope.named_region(span, id)
+    self: &AC,
+    rscope: &RS,
+    default_span: span,
+    opt_lifetime: Option<@ast::Lifetime>) -> ty::Region
+{
+    let (span, res) = match opt_lifetime {
+        None => {
+            (default_span, rscope.anon_region(default_span))
+        }
+        Some(ref lifetime) if lifetime.ident == special_idents::static => {
+            (lifetime.span, Ok(ty::re_static))
+        }
+        Some(ref lifetime) if lifetime.ident == special_idents::self_ => {
+            (lifetime.span, rscope.self_region(lifetime.span))
+        }
+        Some(ref lifetime) => {
+            (lifetime.span, rscope.named_region(lifetime.span,
+                                                lifetime.ident))
+        }
     };
 
-    get_region_reporting_err(self.tcx(), span, Some(a_r), res)
+    get_region_reporting_err(self.tcx(), span, opt_lifetime, res)
 }
 
 pub fn ast_path_to_substs_and_ty<AC:AstConv,RS:region_scope + Copy + Durable>(
@@ -156,8 +161,8 @@ pub fn ast_path_to_substs_and_ty<AC:AstConv,RS:region_scope + Copy + Durable>(
         let r = get_region_reporting_err(self.tcx(), path.span, None, res);
         Some(r)
       }
-      (Some(_), Some(r)) => {
-        Some(ast_region_to_region(self, rscope, path.span, r))
+      (Some(_), Some(_)) => {
+        Some(ast_region_to_region(self, rscope, path.span, path.rp))
       }
     };
 
@@ -504,7 +509,7 @@ pub fn ty_of_closure<AC:AstConv,RS:region_scope + Copy + Durable>(
         sigil: ast::Sigil,
         purity: ast::purity,
         onceness: ast::Onceness,
-        opt_region: Option<@ast::region>,
+        opt_lifetime: Option<@ast::Lifetime>,
         decl: &ast::fn_decl,
         expected_tys: Option<ty::FnSig>,
         span: span)
@@ -514,9 +519,9 @@ pub fn ty_of_closure<AC:AstConv,RS:region_scope + Copy + Durable>(
 
     // resolve the function bound region in the original region
     // scope `rscope`, not the scope of the function parameters
-    let bound_region = match opt_region {
-        Some(region) => {
-            ast_region_to_region(self, rscope, span, region)
+    let bound_region = match opt_lifetime {
+        Some(_) => {
+            ast_region_to_region(self, rscope, span, opt_lifetime)
         }
         None => {
             match sigil {
@@ -526,9 +531,8 @@ pub fn ty_of_closure<AC:AstConv,RS:region_scope + Copy + Durable>(
                     ty::re_static
                 }
                 ast::BorrowedSigil => {
-                    // &fn() defaults to an anonymous region:
-                    let r_result = rscope.anon_region(span);
-                    get_region_reporting_err(self.tcx(), span, None, r_result)
+                    // &fn() defaults as normal for an omitted lifetime:
+                    ast_region_to_region(self, rscope, span, opt_lifetime)
                 }
             }
         }

src/librustc/middle/typeck/check/mod.rs

@@ -2950,19 +2950,19 @@ pub fn instantiate_path(fcx: @mut FnCtxt,
     // determine the region bound, using the value given by the user
     // (if any) and otherwise using a fresh region variable
     let self_r = match pth.rp {
-      Some(r) => {
+      Some(_) => { // user supplied a lifetime parameter...
         match tpt.region_param {
-          None => {
+          None => { // ...but the type is not lifetime parameterized!
             fcx.ccx.tcx.sess.span_err
                 (span, ~"this item is not region-parameterized");
             None
           }
-          Some(_) => {
-            Some(ast_region_to_region(fcx, fcx, span, r))
+          Some(_) => { // ...and the type is lifetime parameterized, ok.
+            Some(ast_region_to_region(fcx, fcx, span, pth.rp))
           }
         }
       }
-      None => {
+      None => { // no lifetime parameter supplied, insert default
         fcx.region_var_if_parameterized(
             tpt.region_param, span, region_lb)
       }

src/libsyntax/ast.rs

@@ -116,7 +116,7 @@ pub struct path {
     span: span,
     global: bool,
     idents: ~[ident],
-    rp: Option<@region>,
+    rp: Option<@Lifetime>,
     types: ~[@Ty],
 }
 
@@ -374,10 +374,10 @@ impl ToStr for Sigil {
 #[deriving_eq]
 pub enum vstore {
     // FIXME (#3469): Change uint to @expr (actually only constant exprs)
-    vstore_fixed(Option<uint>),   // [1,2,3,4]
-    vstore_uniq,                  // ~[1,2,3,4]
-    vstore_box,                   // @[1,2,3,4]
-    vstore_slice(@region)         // &[1,2,3,4](foo)?
+    vstore_fixed(Option<uint>),     // [1,2,3,4]
+    vstore_uniq,                    // ~[1,2,3,4]
+    vstore_box,                     // @[1,2,3,4]
+    vstore_slice(Option<@Lifetime>) // &'foo? [1,2,3,4]
 }
 
 #[auto_encode]
@@ -857,24 +857,6 @@ pub enum prim_ty {
     ty_bool,
 }
 
-#[auto_encode]
-#[auto_decode]
-#[deriving_eq]
-pub struct region {
-    id: node_id,
-    node: region_,
-}
-
-#[auto_encode]
-#[auto_decode]
-#[deriving_eq]
-pub enum region_ {
-    re_anon,
-    re_static,
-    re_self,
-    re_named(ident)
-}
-
 #[auto_encode]
 #[auto_decode]
 #[deriving_eq]
@@ -903,7 +885,7 @@ impl to_bytes::IterBytes for Onceness {
 #[deriving_eq]
 pub struct TyClosure {
     sigil: Sigil,
-    region: Option<@region>,
+    region: Option<@Lifetime>,
     purity: purity,
     onceness: Onceness,
     decl: fn_decl
@@ -929,7 +911,7 @@ pub enum ty_ {
     ty_vec(mt),
     ty_fixed_length_vec(mt, uint),
     ty_ptr(mt),
-    ty_rptr(@region, mt),
+    ty_rptr(Option<@Lifetime>, mt),
     ty_closure(@TyClosure),
     ty_bare_fn(@TyBareFn),
     ty_tup(~[@Ty]),

src/libsyntax/ext/auto_encode.rs

@@ -594,10 +594,7 @@ fn mk_ser_method(
     let ty_s = @ast::Ty {
         id: cx.next_id(),
         node: ast::ty_rptr(
-            @ast::region {
-                id: cx.next_id(),
-                node: ast::re_anon,
-            },
+            None,
             ast::mt {
                 ty: cx.ty_path(span, ~[cx.ident_of(~"__S")], ~[]),
                 mutbl: ast::m_imm
@@ -658,10 +655,7 @@ fn mk_deser_method(
     let ty_d = @ast::Ty {
         id: cx.next_id(),
         node: ast::ty_rptr(
-            @ast::region {
-                id: cx.next_id(),
-                node: ast::re_anon,
-            },
+            None,
             ast::mt {
                 ty: cx.ty_path(span, ~[cx.ident_of(~"__D")], ~[]),
                 mutbl: ast::m_imm

src/libsyntax/ext/deriving.rs

@@ -19,7 +19,7 @@ use ast::{enum_variant_kind, expr, expr_match, ident, impure_fn, item, item_};
 use ast::{item_enum, item_impl, item_struct, Generics};
 use ast::{m_imm, meta_item, method};
 use ast::{named_field, or, pat, pat_ident, pat_wild, public, pure_fn};
-use ast::{re_anon, stmt, struct_def, struct_variant_kind};
+use ast::{stmt, struct_def, struct_variant_kind};
 use ast::{sty_by_ref, sty_region, tuple_variant_kind, ty_nil, TyParam};
 use ast::{TyParamBound, ty_path, ty_rptr, unnamed_field, variant};
 use ext::base::ext_ctxt;
@@ -147,9 +147,8 @@ fn create_eq_method(cx: ext_ctxt,
                                                      span,
                                                      type_ident,
                                                      generics);
-    let arg_region = @ast::region { id: cx.next_id(), node: re_anon };
     let arg_type = ty_rptr(
-        arg_region,
+        None,
         ast::mt { ty: arg_path_type, mutbl: m_imm }
     );
     let arg_type = @ast::Ty {

src/libsyntax/parse/obsolete.rs

@@ -52,6 +52,7 @@ pub enum ObsoleteSyntax {
     ObsoleteRecordType,
     ObsoleteRecordPattern,
     ObsoleteAssertion,
+    ObsoletePostFnTySigil,
 }
 
 impl to_bytes::IterBytes for ObsoleteSyntax {
@@ -160,6 +161,11 @@ pub impl Parser {
                 "assertion",
                 "use `fail_unless!()` instead"
             ),
+            ObsoletePostFnTySigil => (
+                "fn sigil in postfix position",
+                "Rather than `fn@`, `fn~`, or `fn&`, \
+                 write `@fn`, `~fn`, and `&fn` respectively"
+            ),
         };
 
         self.report(sp, kind, kind_str, desc);