---

yaml
---
r: 5267
b: refs/heads/master
c: 51dae63
h: refs/heads/master
i:
  5265: 92eeeed
  5263: 18d9e65
v: v3

Author: marijnh

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: c1c083cd66dd2a6dd46dac3e68210227a67331ab
+refs/heads/master: 51dae63c44f7d82886436c9e90a3e26aa591d9af

trunk/src/comp/metadata/tyencode.rs

@@ -218,7 +218,10 @@ fn enc_ty_fn(w: io::writer, cx: @ctxt, args: [ty::arg], out: ty::t,
         } else { w.write_char(';'); }
         enc_constr(w, cx, c);
     }
-    alt cf { noreturn. { w.write_char('!'); } _ { enc_ty(w, cx, out); } }
+    alt cf {
+      noreturn. { w.write_char('!'); }
+      _ { enc_ty(w, cx, out); }
+    }
 }
 
 // FIXME less copy-and-paste

trunk/src/comp/middle/ty.rs

@@ -279,7 +279,7 @@ type constr = constr_general<uint>;
 // Data structures used in type unification
 tag type_err {
     terr_mismatch;
-    terr_controlflow_mismatch;
+    terr_ret_style_mismatch(ast::ret_style, ast::ret_style);
     terr_box_mutability;
     terr_vec_mutability;
     terr_tuple_size(uint, uint);
@@ -1952,26 +1952,13 @@ mod unify {
                 _expected_constrs: [@constr], actual_constrs: [@constr]) ->
        result {
         if e_proto != a_proto { ret ures_err(terr_mismatch); }
-        alt expected_cf {
-          ast::return_val. { }
-          // ok
-          ast::noreturn. {
-            alt actual_cf {
-              ast::noreturn. {
-                // ok
-
-              }
-              _ {
-                /* even though typestate checking is mostly
-                   responsible for checking control flow annotations,
-                   this check is necessary to ensure that the
-                   annotation in an object method matches the
-                   declared object type */
-
-                ret ures_err(terr_controlflow_mismatch);
-              }
-            }
-          }
+        if actual_cf != ast::noreturn && actual_cf != expected_cf {
+            /* even though typestate checking is mostly
+               responsible for checking control flow annotations,
+               this check is necessary to ensure that the
+               annotation in an object method matches the
+               declared object type */
+            ret ures_err(terr_ret_style_mismatch(expected_cf, actual_cf));
         }
         let t =
             unify_fn_common(cx, expected, actual, expected_inputs,
@@ -2470,9 +2457,16 @@ mod unify {
 fn type_err_to_str(err: ty::type_err) -> str {
     alt err {
       terr_mismatch. { ret "types differ"; }
-      terr_controlflow_mismatch. {
-        ret "returning function used where non-returning function" +
-                " was expected";
+      terr_ret_style_mismatch(expect, actual) {
+        fn to_str(s: ast::ret_style) -> str {
+            alt s {
+              ast::noreturn. { "non-returning" }
+              ast::return_val. { "return-by-value" }
+              ast::return_ref. { "return-by-reference" }
+            }
+        }
+        ret to_str(actual) + " function found where " + to_str(expect) +
+            " function was expected";
       }
       terr_box_mutability. { ret "boxed values differ in mutability"; }
       terr_vec_mutability. { ret "vectors differ in mutability"; }

trunk/src/comp/syntax/print/pprust.rs

@@ -1224,6 +1224,7 @@ fn print_fn_args_and_ret(s: ps, decl: ast::fn_decl, constrs: [@ast::constr]) {
     if decl.output.node != ast::ty_nil {
         space_if_not_bol(s);
         word_space(s, "->");
+        if decl.cf == ast::return_ref { word(s.s, "&"); }
         print_type(s, decl.output);
     }
 }
@@ -1419,9 +1420,11 @@ fn print_ty_fn(s: ps, proto: ast::proto, id: option::t<ast::ident>,
         space_if_not_bol(s);
         ibox(s, indent_unit);
         word_space(s, "->");
-        alt cf {
-          ast::return_val. { print_type(s, output); }
-          ast::noreturn. { word_nbsp(s, "!"); }
+        if cf == ast::noreturn {
+            word_nbsp(s, "!")
+        } else {
+            if cf == ast::return_ref { word(s.s, "&"); }
+            print_type(s, output);
         }
         end(s);
     }

trunk/src/comp/util/ppaux.rs

@@ -58,9 +58,12 @@ fn ty_to_str(cx: ctxt, typ: t) -> str {
         s += str::connect(strs, ", ");
         s += ")";
         if struct(cx, output) != ty_nil {
-            alt cf {
-              ast::noreturn. { s += " -> !"; }
-              ast::return_val. { s += " -> " + ty_to_str(cx, output); }
+            s += " -> ";
+            if cf == ast::noreturn {
+                s += "!";
+            } else {
+                if cf == ast::return_ref { s += "&"; }
+                s += ty_to_str(cx, output);
             }
         }
         s += constrs_str(constrs);