From 37acac4b972b38e8dbe2d174dae1031e5a8eda67 Mon Sep 17 00:00:00 2001 From: Nadrieril Date: Fri, 17 Jan 2020 16:09:35 +0000 Subject: Tweak: handle empty lists in typeck --- dhall/src/semantics/phase/normalize.rs | 20 ++++---------------- dhall/src/semantics/phase/typecheck.rs | 14 ++++++++++---- 2 files changed, 14 insertions(+), 20 deletions(-) diff --git a/dhall/src/semantics/phase/normalize.rs b/dhall/src/semantics/phase/normalize.rs index 615b2ff..8f9a58a 100644 --- a/dhall/src/semantics/phase/normalize.rs +++ b/dhall/src/semantics/phase/normalize.rs @@ -590,9 +590,9 @@ pub(crate) fn normalize_one_layer( ty: &Value, ) -> ValueKind { use ValueKind::{ - AppliedBuiltin, BoolLit, DoubleLit, EmptyListLit, EmptyOptionalLit, - IntegerLit, NEListLit, NEOptionalLit, NaturalLit, RecordLit, TextLit, - UnionConstructor, UnionLit, UnionType, + BoolLit, DoubleLit, EmptyOptionalLit, IntegerLit, NEListLit, + NEOptionalLit, NaturalLit, RecordLit, TextLit, UnionConstructor, + UnionLit, UnionType, }; let ret = match expr { @@ -609,6 +609,7 @@ pub(crate) fn normalize_one_layer( | ExprKind::Builtin(_) | ExprKind::Var(_) | ExprKind::Annot(_, _) + | ExprKind::EmptyListLit(_) | ExprKind::RecordType(_) | ExprKind::UnionType(_) => { unreachable!("This case should have been handled in typecheck") @@ -620,19 +621,6 @@ pub(crate) fn normalize_one_layer( ExprKind::IntegerLit(n) => Ret::ValueKind(IntegerLit(n)), ExprKind::DoubleLit(n) => Ret::ValueKind(DoubleLit(n)), ExprKind::SomeLit(e) => Ret::ValueKind(NEOptionalLit(e)), - ExprKind::EmptyListLit(ref t) => { - // Check if the type is of the form `List x` - let t_borrow = t.as_whnf(); - match &*t_borrow { - AppliedBuiltin(Builtin::List, args) if args.len() == 1 => { - Ret::ValueKind(EmptyListLit(args[0].clone())) - } - _ => { - drop(t_borrow); - Ret::Expr(expr) - } - } - } ExprKind::NEListLit(elts) => { Ret::ValueKind(NEListLit(elts.into_iter().collect())) } diff --git a/dhall/src/semantics/phase/typecheck.rs b/dhall/src/semantics/phase/typecheck.rs index c77d9c4..852f41b 100644 --- a/dhall/src/semantics/phase/typecheck.rs +++ b/dhall/src/semantics/phase/typecheck.rs @@ -433,12 +433,18 @@ fn type_last_layer( RetTypeOnly(y.get_type()?) } EmptyListLit(t) => { - match &*t.as_whnf() { + let arg = match &*t.as_whnf() { ValueKind::AppliedBuiltin(syntax::Builtin::List, args) - if args.len() == 1 => {} + if args.len() == 1 => + { + args[0].clone() + } _ => return mkerr(InvalidListType(t.clone())), - } - RetTypeOnly(t.clone()) + }; + RetWhole(Value::from_kind_and_type( + ValueKind::EmptyListLit(arg), + t.clone(), + )) } NEListLit(xs) => { let mut iter = xs.iter().enumerate(); -- cgit v1.2.3