Fix trans for foreign methods

src/librustc_trans/trans/base.rs

@@ -301,7 +301,7 @@ pub fn decl_rust_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
                    self_type.repr(ccx.tcx()));
             (&function_type.sig, RustCall, Some(llenvironment_type))
         }
-        _ => panic!("expected closure or fn")
+        _ => ccx.sess().bug("expected closure or fn")
     };
 
     let sig = ty::erase_late_bound_regions(ccx.tcx(), sig);
@@ -2410,12 +2410,15 @@ fn register_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
                          node_id: ast::NodeId,
                          node_type: Ty<'tcx>)
                          -> ValueRef {
-    match node_type.sty {
-        ty::ty_bare_fn(_, ref f) => {
-            assert!(f.abi == Rust || f.abi == RustCall);
+    if let ty::ty_bare_fn(_, ref f) = node_type.sty {
+        if f.abi != Rust && f.abi != RustCall {
+            ccx.sess().span_bug(sp, &format!("only the `{}` or `{}` calling conventions are valid \
+                                              for this function; `{}` was specified",
+                                              Rust.name(), RustCall.name(), f.abi.name()));
         }
-        _ => panic!("expected bare rust fn")
-    };
+    } else {
+        ccx.sess().span_bug(sp, "expected bare rust function")
+    }
 
     let llfn = decl_rust_fn(ccx, node_type, &sym[..]);
     finish_register_fn(ccx, sp, sym, node_id, llfn);
@@ -2802,7 +2805,7 @@ pub fn get_item_val(ccx: &CrateContext, id: ast::NodeId) -> ValueRef {
                     llfn
                 }
 
-                _ => panic!("get_item_val: weird result in table")
+                _ => ccx.sess().bug("get_item_val: weird result in table")
             };
 
             match attr::first_attr_value_str_by_name(&i.attrs,
@@ -2866,7 +2869,7 @@ pub fn get_item_val(ccx: &CrateContext, id: ast::NodeId) -> ValueRef {
             let args = match v.node.kind {
                 ast::TupleVariantKind(ref args) => args,
                 ast::StructVariantKind(_) => {
-                    panic!("struct variant kind unexpected in get_item_val")
+                    ccx.sess().bug("struct variant kind unexpected in get_item_val")
                 }
             };
             assert!(args.len() != 0);
@@ -2882,7 +2885,7 @@ pub fn get_item_val(ccx: &CrateContext, id: ast::NodeId) -> ValueRef {
                 ast::ItemEnum(_, _) => {
                     register_fn(ccx, (*v).span, sym, id, ty)
                 }
-                _ => panic!("NodeVariant, shouldn't happen")
+                _ => ccx.sess().bug("NodeVariant, shouldn't happen")
             };
             set_inline_hint(llfn);
             llfn
@@ -2935,9 +2938,17 @@ fn register_method(ccx: &CrateContext, id: ast::NodeId,
 
     let sym = exported_name(ccx, id, mty, &m.attrs);
 
-    let llfn = register_fn(ccx, m.span, sym, id, mty);
-    set_llvm_fn_attrs(ccx, &m.attrs, llfn);
-    llfn
+    if let ty::ty_bare_fn(_, ref f) = mty.sty {
+        let llfn = if f.abi == Rust || f.abi == RustCall {
+            register_fn(ccx, m.span, sym, id, mty)
+        } else {
+            foreign::register_rust_fn_with_foreign_abi(ccx, m.span, sym, id)
+        };
+        set_llvm_fn_attrs(ccx, &m.attrs, llfn);
+        return llfn;
+    } else {
+        ccx.sess().span_bug(m.span, "expected bare rust function");
+    }
 }
 
 pub fn crate_ctxt_to_encode_parms<'a, 'tcx>(cx: &'a SharedCrateContext<'tcx>,

src/test/run-pass/extern-methods.rs

@@ -0,0 +1,35 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+trait A {
+    extern "fastcall" fn test1(i: i32);
+    extern fn test2(i: i32);
+}
+
+struct S;
+impl S {
+    extern "stdcall" fn test3(i: i32) {
+        assert_eq!(i, 3);
+    }
+}
+
+impl A for S {
+    extern "fastcall" fn test1(i: i32) {
+        assert_eq!(i, 1);
+    }
+    extern fn test2(i: i32) {
+        assert_eq!(i, 2);
+    }
+}
+
+fn main() {
+    <S as A>::test1(1);
+    <S as A>::test2(2);
+    S::test3(3);
+}