From 6ed8d037841aab1b2855525bf141c5c1c4de4910 Mon Sep 17 00:00:00 2001
From: Marijn Haverbeke <marijnh@gmail.com>
Date: Mon, 6 Feb 2012 09:51:03 +0100
Subject: [PATCH] Make sure iface_methods are set before they are accessed

Closes #1761
---
 src/comp/middle/typeck.rs                 | 21 ++++++++++++++++++---
 src/test/run-pass/use-iface-before-def.rs |  5 +++++
 2 files changed, 23 insertions(+), 3 deletions(-)
 create mode 100644 src/test/run-pass/use-iface-before-def.rs

diff --git a/src/comp/middle/typeck.rs b/src/comp/middle/typeck.rs
index adc276ee335..e626d2089e8 100644
--- a/src/comp/middle/typeck.rs
+++ b/src/comp/middle/typeck.rs
@@ -366,6 +366,10 @@ fn ast_ty_to_ty(tcx: ty::ctxt, mode: mode, &&ast_ty: @ast::ty) -> ty::t {
 
 fn ty_of_item(tcx: ty::ctxt, mode: mode, it: @ast::item)
     -> ty::ty_param_bounds_and_ty {
+    alt tcx.tcache.find(local_def(it.id)) {
+      some(tpt) { ret tpt; }
+      _ {}
+    }
     alt it.node {
       ast::item_const(t, _) {
         let typ = ast_ty_to_ty(tcx, mode, t);
@@ -740,6 +744,16 @@ mod collect {
             write_ty(cx.tcx, variant.node.id, result_ty);
         }
     }
+    fn ensure_iface_methods(tcx: ty::ctxt, id: ast::node_id) {
+        alt tcx.items.get(id) {
+          ast_map::node_item(@{node: ast::item_iface(_, ms), _}, _) {
+            ty::store_iface_methods(tcx, id, @vec::map(ms, {|m|
+                ty_of_ty_method(tcx, m_collect, m)
+            }));
+          }
+          _ { fail; }
+        }
+    }
     fn convert(cx: @ctxt, it: @ast::item) {
         alt it.node {
           // These don't define types.
@@ -771,6 +785,9 @@ mod collect {
                                      {bounds: i_bounds, ty: iface_ty});
                 alt ty::struct(cx.tcx, iface_ty) {
                   ty::ty_iface(did, tys) {
+                    if did.crate == ast::local_crate {
+                        ensure_iface_methods(cx.tcx, did.node);
+                    }
                     for if_m in *ty::iface_methods(cx.tcx, did) {
                         alt vec::find(my_methods,
                                       {|m| if_m.ident == m.mty.ident}) {
@@ -827,9 +844,7 @@ mod collect {
           ast::item_iface(_, ms) {
             let tpt = ty_of_item(cx.tcx, m_collect, it);
             write_ty(cx.tcx, it.id, tpt.ty);
-            ty::store_iface_methods(cx.tcx, it.id, @vec::map(ms, {|m|
-                ty_of_ty_method(cx.tcx, m_collect, m)
-            }));
+            ensure_iface_methods(cx.tcx, it.id);
           }
           _ {
             // This call populates the type cache with the converted type
diff --git a/src/test/run-pass/use-iface-before-def.rs b/src/test/run-pass/use-iface-before-def.rs
new file mode 100644
index 00000000000..aa981e2fb4b
--- /dev/null
+++ b/src/test/run-pass/use-iface-before-def.rs
@@ -0,0 +1,5 @@
+// Issue #1761
+
+impl of foo for int { fn foo() -> int { 10 } }
+iface foo { fn foo() -> int; }
+fn main() {}
\ No newline at end of file