user0/rust
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Catch forward declarations in default type params at AST conversion.

Browse source
This commit is contained in:
Kevin Butler 2014-04-17 01:17:23 +01:00
parent 52a53e8ae7
commit f829d208a3
2 changed files with 19 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

19
src/librustc/middle/typeck/collect.rs
View file

@ -945,7 +945,24 @@ pub fn ty_generics(ccx: &CrateCtxt,
let param_ty = ty::param_ty {idx: base_index + offset,
def_id: local_def(param.id)};
let bounds = @compute_bounds(ccx, param_ty, &param.bounds);
let default = param.default.map(|x| ast_ty_to_ty(ccx, &ExplicitRscope, x));
let default = param.default.map(|path| {
let ty = ast_ty_to_ty(ccx, &ExplicitRscope, path);
let cur_idx = param_ty.idx;
ty::walk_ty(ty, |t| {
match ty::get(t).sty {
ty::ty_param(p) => if p.idx > cur_idx {
ccx.tcx.sess.span_err(path.span,
"type parameters with a default cannot use \
forward declared identifiers")
},
_ => {}
}
});
ty
});
let def = ty::TypeParameterDef {
ident: param.ident,
def_id: local_def(param.id),

3
src/test/compile-fail/generic-type-params-forward-mention.rs
View file

@ -12,8 +12,7 @@
// Ensure that we get an error and not an ICE for this problematic case.
struct Foo<T = Option<U>, U = bool>;
//~^ ERROR type parameters with a default cannot use forward declared identifiers
fn main() {
let x: Foo;
//~^ ERROR missing type param `U` in the substitution of `std::option::Option<U>`
}