bjoernager/rust
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lowering of generic args in AssocTyConstraint

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This commit is contained in:
b-naber 2020-11-30 09:24:54 +01:00
parent 16af7bf3d9
commit 760a6654fb
2 changed files with 37 additions and 9 deletions
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39
compiler/rustc_ast_lowering/src/lib.rs
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@ -1076,16 +1076,40 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
fn lower_assoc_ty_constraint(
&mut self,
constraint: &AssocTyConstraint,
itctx: ImplTraitContext<'_, 'hir>,
mut itctx: ImplTraitContext<'_, 'hir>,
) -> hir::TypeBinding<'hir> {
debug!("lower_assoc_ty_constraint(constraint={:?}, itctx={:?})", constraint, itctx);
if let Some(ref gen_args) = constraint.gen_args {
self.sess.span_fatal(
gen_args.span(),
"generic associated types in trait paths are currently not implemented",
);
}
// lower generic arguments of identifier in constraint
let gen_args = if let Some(ref gen_args) = constraint.gen_args {
let gen_args_ctor = match gen_args {
GenericArgs::AngleBracketed(ref data) => {
self.lower_angle_bracketed_parameter_data(
data,
ParamMode::Explicit,
itctx.reborrow(),
)
.0
}
GenericArgs::Parenthesized(ref data) => {
let mut err = self.sess.struct_span_err(
gen_args.span(),
"parenthesized generic arguments cannot be used in associated type constraints"
);
// FIXME: try to write a suggestion here
err.emit();
self.lower_angle_bracketed_parameter_data(
&data.as_angle_bracketed_args(),
ParamMode::Explicit,
itctx.reborrow(),
)
.0
}
};
self.arena.alloc(gen_args_ctor.into_generic_args(&self.arena))
} else {
self.arena.alloc(hir::GenericArgs::none())
};
let kind = match constraint.kind {
AssocTyConstraintKind::Equality { ref ty } => {
@ -1182,6 +1206,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
hir::TypeBinding {
hir_id: self.lower_node_id(constraint.id),
ident: constraint.ident,
gen_args,
kind,
span: constraint.span,
}