// bounds to see if they include the trait we are looking for.
let vtable_opt = match ty::get(ty).sty {
ty::ty_param(param_ty {idx: n, ..}) => {
- let type_param_bounds: &[@ty::TraitRef] =
- vcx.param_env
- .type_param_bounds
- .get(n)
- .trait_bounds
- .as_slice();
- lookup_vtable_from_bounds(vcx, span,
- type_param_bounds,
- param_numbered(n),
- trait_ref)
+ let env_bounds = &vcx.param_env.type_param_bounds;
+ if env_bounds.len() > n {
+ let type_param_bounds: &[@ty::TraitRef] =
+ env_bounds.get(n).trait_bounds.as_slice();
+ lookup_vtable_from_bounds(vcx, span,
+ type_param_bounds,
+ param_numbered(n),
+ trait_ref)
+ } else {
+ None
+ }
}
ty::ty_self(_) => {
ty_param(param_ty {idx: id, def_id: did}) => {
let ident = match cx.ty_param_defs.borrow().find(&did.node) {
Some(def) => token::get_ident(def.ident).get().to_str(),
- // This should not happen...
- None => format!("BUG[{:?}]", id)
+ // This can only happen when a type mismatch error happens and
+ // the actual type has more type parameters than the expected one.
+ None => format!("<generic \\#{}>", id)
};
if !cx.sess.verbose() {
ident
--- /dev/null
+// Copyright 2014 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.
+
+// Regression test for #13466
+
+pub fn main() {
+ // The expected arm type `Option<T>` has one type parameter, while
+ // the actual arm `Result<T, E>` has two. typeck should not be
+ // tricked into looking up a non-existing second type parameter.
+ let _x: uint = match Some(1u) {
+ //~^ ERROR mismatched types: expected `uint` but found `<generic #0>`
+ Ok(u) => u, //~ ERROR mismatched types: expected `std::option::Option<uint>`
+ Err(e) => fail!(e) //~ ERROR mismatched types: expected `std::option::Option<uint>`
+ };
+}