---

yaml
---
r: 37554
b: refs/heads/try
c: 3e14ada
h: refs/heads/master
v: v3

Author: pcwalton

[refs]

@@ -2,7 +2,7 @@
 refs/heads/master: 09bb07bed9166105ea961a42b5fff7739ae0d2e9
 refs/heads/snap-stage1: e33de59e47c5076a89eadeb38f4934f58a3618a6
 refs/heads/snap-stage3: eb8fd119c65c67f3b1b8268cc7341c22d39b7b61
-refs/heads/try: bad62dcb04d78c53911dc464663c04b47c5215ac
+refs/heads/try: 3e14ada4f6782f1379abe498b2b2d9681f489e26
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
 refs/heads/try2: a810c03263670238bccd64cabb12a23a46e3a278

branches/try/src/librustc/middle/typeck/check.rs

@@ -868,6 +868,16 @@ fn check_expr_with(fcx: @fn_ctxt, expr: @ast::expr, expected: ty::t) -> bool {
     check_expr(fcx, expr, Some(expected))
 }
 
+fn check_expr_with_assignability(fcx: @fn_ctxt,
+                                 expr: @ast::expr,
+                                 expected: ty::t)
+                              -> bool {
+    do check_expr_with_unifier(fcx, expr, Some(expected)) {
+        demand::assign(fcx, expr.span, expected, expr)
+    }
+}
+
+
 fn check_expr(fcx: @fn_ctxt, expr: @ast::expr,
               expected: Option<ty::t>) -> bool {
     return do check_expr_with_unifier(fcx, expr, expected) {
@@ -1072,11 +1082,7 @@ fn check_expr_with_unifier(fcx: @fn_ctxt,
                         DontDerefArgs => {}
                     }
 
-                    bot |= check_expr_with_unifier(
-                        fcx, *arg, Some(formal_ty),
-                        || demand::assign(fcx, arg.span,
-                                           formal_ty, *arg)
-                    );
+                    bot |= check_expr_with_assignability(fcx, *arg, formal_ty);
                     fcx.write_ty(arg.id, fcx.expr_ty(*arg));
 
                 }
@@ -1087,10 +1093,14 @@ fn check_expr_with_unifier(fcx: @fn_ctxt,
     }
 
     // A generic function for checking assignment expressions
-    fn check_assignment(fcx: @fn_ctxt, _sp: span, lhs: @ast::expr,
-                        rhs: @ast::expr, id: ast::node_id) -> bool {
+    fn check_assignment(fcx: @fn_ctxt,
+                        lhs: @ast::expr,
+                        rhs: @ast::expr,
+                        id: ast::node_id)
+                     -> bool {
         let mut bot = check_expr(fcx, lhs, None);
-        bot |= check_expr_with(fcx, rhs, fcx.expr_ty(lhs));
+        let lhs_type = fcx.expr_ty(lhs);
+        bot |= check_expr_with_assignability(fcx, rhs, lhs_type);
         fcx.write_ty(id, ty::mk_nil(fcx.ccx.tcx));
         return bot;
     }
@@ -1908,10 +1918,10 @@ fn check_expr_with_unifier(fcx: @fn_ctxt,
         };
       }
       ast::expr_assign(lhs, rhs) => {
-        bot = check_assignment(fcx, expr.span, lhs, rhs, id);
+        bot = check_assignment(fcx, lhs, rhs, id);
       }
       ast::expr_swap(lhs, rhs) => {
-        bot = check_assignment(fcx, expr.span, lhs, rhs, id);
+        bot = check_assignment(fcx, lhs, rhs, id);
       }
       ast::expr_if(cond, thn, elsopt) => {
         bot = check_expr_with(fcx, cond, ty::mk_bool(tcx)) |
@@ -2246,7 +2256,7 @@ fn require_integral(fcx: @fn_ctxt, sp: span, t: ty::t) {
 fn check_decl_initializer(fcx: @fn_ctxt, nid: ast::node_id,
                           init: @ast::expr) -> bool {
     let lty = ty::mk_var(fcx.ccx.tcx, lookup_local(fcx, init.span, nid));
-    return check_expr_with(fcx, init, lty);
+    return check_expr_with_assignability(fcx, init, lty);
 }
 
 fn check_decl_local(fcx: @fn_ctxt, local: @ast::local) -> bool {

branches/try/src/test/run-pass/let-assignability.rs

@@ -0,0 +1,18 @@
+fn f() {
+    let a = ~"hello";
+    let b: &str = a;
+    io::println(b);
+}
+
+fn g() {
+    let c = ~"world";
+    let d: &str;
+    d = c;
+    io::println(d);
+}
+
+fn main() {
+    f();
+    g();
+}
+