From fa6de4c077ab4f1c28d2ec64a33a3be8c5a9bb1c Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Sun, 22 Dec 2019 18:24:21 +0000
Subject: Update dhall-lang submodule

---
 dhall/src/error/mod.rs                 |  1 +
 dhall/src/semantics/phase/typecheck.rs | 10 +++++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

(limited to 'dhall/src')

diff --git a/dhall/src/error/mod.rs b/dhall/src/error/mod.rs
index 1288c12..40cccac 100644
--- a/dhall/src/error/mod.rs
+++ b/dhall/src/error/mod.rs
@@ -76,6 +76,7 @@ pub(crate) enum TypeMessage {
     MergeHandlerReturnTypeMustNotBeDependent,
     ProjectionMustBeRecord,
     ProjectionMissingEntry,
+    ProjectionDuplicateField,
     Sort,
     RecordTypeDuplicateField,
     RecordTypeMergeRequiresRecordType(Value),
diff --git a/dhall/src/semantics/phase/typecheck.rs b/dhall/src/semantics/phase/typecheck.rs
index c439f74..856f5c3 100644
--- a/dhall/src/semantics/phase/typecheck.rs
+++ b/dhall/src/semantics/phase/typecheck.rs
@@ -774,7 +774,15 @@ fn type_last_layer(
             for l in labels {
                 match kts.get(l) {
                     None => return mkerr(ProjectionMissingEntry),
-                    Some(t) => new_kts.insert(l.clone(), t.clone()),
+                    Some(t) => {
+                        use std::collections::hash_map::Entry;
+                        match new_kts.entry(l.clone()) {
+                            Entry::Occupied(_) => {
+                                return mkerr(ProjectionDuplicateField)
+                            }
+                            Entry::Vacant(e) => e.insert(t.clone()),
+                        }
+                    }
                 };
             }
 
-- 
cgit v1.3.1


From 54d7e61ad40682ee24e36288980ee4164ea87c34 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Sun, 22 Dec 2019 18:38:05 +0000
Subject: Update dhall-lang submodule

---
 dhall-lang                                         | 2 +-
 dhall/build.rs                                     | 7 +------
 dhall/src/syntax/text/printer.rs                   | 2 ++
 dhall/tests/type-errors/unit/AssertDoubleZeros.txt | 1 +
 4 files changed, 5 insertions(+), 7 deletions(-)
 create mode 100644 dhall/tests/type-errors/unit/AssertDoubleZeros.txt

(limited to 'dhall/src')

diff --git a/dhall-lang b/dhall-lang
index 1457988..b760b41 160000
--- a/dhall-lang
+++ b/dhall-lang
@@ -1 +1 @@
-Subproject commit 145798835f4ea7e4b30f1eccd651e9f25cca1e2c
+Subproject commit b760b4183c8c589e3572a7f9e049d60e69ca53dd
diff --git a/dhall/build.rs b/dhall/build.rs
index 3e7c023..e06f9b3 100644
--- a/dhall/build.rs
+++ b/dhall/build.rs
@@ -224,6 +224,7 @@ fn generate_tests() -> std::io::Result<()> {
                     || path == "hashMismatch"
                     || path == "missing"
                     || path == "referentiallyInsane"
+                    || path == "customHeadersUsingBoundVariable"
             }),
             input_type: FileType::Text,
             output_type: None,
@@ -308,9 +309,6 @@ fn generate_tests() -> std::io::Result<()> {
             variant: "TypeInferenceFailure",
             path_filter: Box::new(|path: &str| {
                 false
-                    // TODO: Enable imports in typecheck tests
-                    || path == "importBoundary"
-                    || path == "customHeadersUsingBoundVariable"
                     // TODO: projection by expression
                     || path == "unit/RecordProjectionByTypeFieldTypeMismatch"
                     || path == "unit/RecordProjectionByTypeNotPresent"
@@ -334,9 +332,6 @@ fn generate_tests() -> std::io::Result<()> {
             variant: "TypeError",
             path_filter: Box::new(|path: &str| {
                 false
-                    // TODO: Enable imports in typecheck tests
-                    || path == "importBoundary"
-                    || path == "customHeadersUsingBoundVariable"
                     // TODO: projection by expression
                     || path == "unit/RecordProjectionByTypeFieldTypeMismatch"
                     || path == "unit/RecordProjectionByTypeNotPresent"
diff --git a/dhall/src/syntax/text/printer.rs b/dhall/src/syntax/text/printer.rs
index 78942ed..dff3479 100644
--- a/dhall/src/syntax/text/printer.rs
+++ b/dhall/src/syntax/text/printer.rs
@@ -322,6 +322,8 @@ impl Display for NaiveDouble {
             f.write_str("-Infinity")
         } else if v.is_nan() {
             f.write_str("NaN")
+        } else if v == 0.0 && v.is_sign_negative() {
+            f.write_str("-0.0")
         } else {
             let s = format!("{}", v);
             if s.contains('e') || s.contains('.') {
diff --git a/dhall/tests/type-errors/unit/AssertDoubleZeros.txt b/dhall/tests/type-errors/unit/AssertDoubleZeros.txt
new file mode 100644
index 0000000..4b68fea
--- /dev/null
+++ b/dhall/tests/type-errors/unit/AssertDoubleZeros.txt
@@ -0,0 +1 @@
+Type error: Unhandled error
-- 
cgit v1.3.1


From e294450e1e76491e96019b8a3695463e09d1739b Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Sun, 22 Dec 2019 19:02:18 +0000
Subject: Implement parsing for record completion

---
 dhall-lang                             |  2 +-
 dhall/build.rs                         | 16 ++++++++++++++++
 dhall/src/dhall.pest.visibility        |  2 ++
 dhall/src/semantics/phase/normalize.rs |  1 +
 dhall/src/semantics/phase/typecheck.rs |  1 +
 dhall/src/syntax/ast/expr.rs           |  2 ++
 dhall/src/syntax/ast/visitor.rs        |  7 +++++++
 dhall/src/syntax/binary/decode.rs      |  5 +++++
 dhall/src/syntax/binary/encode.rs      |  3 +++
 dhall/src/syntax/text/parser.rs        | 19 +++++++++++++++++++
 dhall/src/syntax/text/printer.rs       | 20 ++++++++++++--------
 11 files changed, 69 insertions(+), 9 deletions(-)

(limited to 'dhall/src')

diff --git a/dhall-lang b/dhall-lang
index b760b41..e95d863 160000
--- a/dhall-lang
+++ b/dhall-lang
@@ -1 +1 @@
-Subproject commit b760b4183c8c589e3572a7f9e049d60e69ca53dd
+Subproject commit e95d863766356c3b5a299c1db1c299df7a315294
diff --git a/dhall/build.rs b/dhall/build.rs
index e06f9b3..ec06ece 100644
--- a/dhall/build.rs
+++ b/dhall/build.rs
@@ -267,6 +267,9 @@ fn generate_tests() -> std::io::Result<()> {
                     || path == "unit/RightBiasedMergeEquivalentArguments"
                     || path == "unit/NestedRecordProjection"
                     || path == "unit/NestedRecordProjectionByType"
+                    // TODO: record completion
+                    || path == "simple/completion"
+                    || path == "unit/Completion"
             }),
             input_type: FileType::Text,
             output_type: Some(FileType::Text),
@@ -299,6 +302,9 @@ fn generate_tests() -> std::io::Result<()> {
                     || path == "unit/ToMapAnnotated"
                     || path == "unit/ToMapInferTypeFromRecord"
                     || path == "simple/toMapEmptyNormalizeAnnotation"
+                    // TODO: record completion
+                    || path == "simple/completion"
+                    || path == "unit/Completion"
             }),
             input_type: FileType::Text,
             output_type: Some(FileType::Text),
@@ -322,6 +328,11 @@ fn generate_tests() -> std::io::Result<()> {
                     || path == "unit/NonRecordToMap"
                     || path == "unit/ToMapEmptyInvalidAnnotation"
                     || path == "unit/ToMapWrongKind"
+                    // TODO: record completion
+                    || path == "unit/CompletionMissingRequiredField"
+                    || path == "unit/CompletionWithWrongDefaultType"
+                    || path == "unit/CompletionWithWrongFieldName"
+                    || path == "unit/CompletionWithWrongOverridenType"
             }),
             input_type: FileType::Text,
             output_type: None,
@@ -345,6 +356,11 @@ fn generate_tests() -> std::io::Result<()> {
                     || path == "unit/NonRecordToMap"
                     || path == "unit/ToMapEmptyInvalidAnnotation"
                     || path == "unit/ToMapWrongKind"
+                    // TODO: record completion
+                    || path == "unit/CompletionMissingRequiredField"
+                    || path == "unit/CompletionWithWrongDefaultType"
+                    || path == "unit/CompletionWithWrongFieldName"
+                    || path == "unit/CompletionWithWrongOverridenType"
             }),
             input_type: FileType::Text,
             output_type: None,
diff --git a/dhall/src/dhall.pest.visibility b/dhall/src/dhall.pest.visibility
index 17c1edc..41aa833 100644
--- a/dhall/src/dhall.pest.visibility
+++ b/dhall/src/dhall.pest.visibility
@@ -91,6 +91,7 @@ prefer
 lambda
 forall
 arrow
+# complete
 # exponent
 numeric_double_literal
 minus_infinity_literal
@@ -161,6 +162,7 @@ equivalent_expression
 application_expression
 first_application_expression
 # import_expression
+completion_expression
 selector_expression
 selector
 labels
diff --git a/dhall/src/semantics/phase/normalize.rs b/dhall/src/semantics/phase/normalize.rs
index d81a910..65384c2 100644
--- a/dhall/src/semantics/phase/normalize.rs
+++ b/dhall/src/semantics/phase/normalize.rs
@@ -741,6 +741,7 @@ pub(crate) fn normalize_one_layer(
         ExprKind::ProjectionByExpr(_, _) => {
             unimplemented!("selection by expression")
         }
+        ExprKind::Completion(_, _) => unimplemented!("record completion"),
 
         ExprKind::Merge(ref handlers, ref variant, _) => {
             let handlers_borrow = handlers.as_whnf();
diff --git a/dhall/src/semantics/phase/typecheck.rs b/dhall/src/semantics/phase/typecheck.rs
index 856f5c3..c9834e1 100644
--- a/dhall/src/semantics/phase/typecheck.rs
+++ b/dhall/src/semantics/phase/typecheck.rs
@@ -792,6 +792,7 @@ fn type_last_layer(
             ))
         }
         ProjectionByExpr(_, _) => unimplemented!("selection by expression"),
+        Completion(_, _) => unimplemented!("record completion"),
     };
 
     Ok(match ret {
diff --git a/dhall/src/syntax/ast/expr.rs b/dhall/src/syntax/ast/expr.rs
index 48c48d8..fe49448 100644
--- a/dhall/src/syntax/ast/expr.rs
+++ b/dhall/src/syntax/ast/expr.rs
@@ -163,6 +163,8 @@ pub enum ExprKind<SubExpr, Embed> {
     Projection(SubExpr, DupTreeSet<Label>),
     ///  `e.(t)`
     ProjectionByExpr(SubExpr, SubExpr),
+    ///  `x::y`
+    Completion(SubExpr, SubExpr),
     /// `./some/path`
     Import(Import<SubExpr>),
     /// Embeds the result of resolving an import
diff --git a/dhall/src/syntax/ast/visitor.rs b/dhall/src/syntax/ast/visitor.rs
index b557995..424048b 100644
--- a/dhall/src/syntax/ast/visitor.rs
+++ b/dhall/src/syntax/ast/visitor.rs
@@ -164,6 +164,9 @@ where
         ProjectionByExpr(e, x) => {
             ProjectionByExpr(v.visit_subexpr(e)?, v.visit_subexpr(x)?)
         }
+        Completion(e, x) => {
+            Completion(v.visit_subexpr(e)?, v.visit_subexpr(x)?)
+        }
         Assert(e) => Assert(v.visit_subexpr(e)?),
         Import(i) => Import(i.traverse_ref(|e| v.visit_subexpr(e))?),
         Embed(a) => Embed(v.visit_embed(a)?),
@@ -281,6 +284,10 @@ where
             v.visit_subexpr(e)?;
             v.visit_subexpr(x)?;
         }
+        Completion(x, y) => {
+            v.visit_subexpr(x)?;
+            v.visit_subexpr(y)?;
+        }
         Assert(e) => v.visit_subexpr(e)?,
         Import(i) => i.traverse_mut(|e| v.visit_subexpr(e))?,
         Embed(a) => v.visit_embed(a)?,
diff --git a/dhall/src/syntax/binary/decode.rs b/dhall/src/syntax/binary/decode.rs
index 254ab07..c18deb5 100644
--- a/dhall/src/syntax/binary/decode.rs
+++ b/dhall/src/syntax/binary/decode.rs
@@ -98,6 +98,11 @@ fn cbor_value_to_dhall(data: &cbor::Value) -> Result<DecodedExpr, DecodeError> {
                 let l = Label::from(l.as_str());
                 Pi(l, x, y)
             }
+            [U64(3), U64(13), x, y] => {
+                let x = cbor_value_to_dhall(&x)?;
+                let y = cbor_value_to_dhall(&y)?;
+                Completion(x, y)
+            }
             [U64(3), U64(n), x, y] => {
                 let x = cbor_value_to_dhall(&x)?;
                 let y = cbor_value_to_dhall(&y)?;
diff --git a/dhall/src/syntax/binary/encode.rs b/dhall/src/syntax/binary/encode.rs
index 25a545c..867fc9c 100644
--- a/dhall/src/syntax/binary/encode.rs
+++ b/dhall/src/syntax/binary/encode.rs
@@ -164,6 +164,9 @@ where
         ProjectionByExpr(x, y) => {
             ser_seq!(ser; tag(10), expr(x), vec![expr(y)])
         }
+        Completion(x, y) => {
+            ser_seq!(ser; tag(3), tag(13), expr(x), expr(y))
+        }
         Import(import) => serialize_import(ser, import),
         Embed(_) => unimplemented!(
             "An expression with resolved imports cannot be binary-encoded"
diff --git a/dhall/src/syntax/text/parser.rs b/dhall/src/syntax/text/parser.rs
index 832472b..fe34aee 100644
--- a/dhall/src/syntax/text/parser.rs
+++ b/dhall/src/syntax/text/parser.rs
@@ -765,6 +765,25 @@ impl DhallParser {
         ))
     }
 
+    #[alias(expression, shortcut = true)]
+    fn completion_expression(input: ParseInput) -> ParseResult<Expr> {
+        Ok(match_nodes!(input.children();
+            [expression(e)] => e,
+            [expression(first), expression(rest)..] => {
+                rest.fold(
+                    first,
+                    |acc, e| {
+                        spanned_union(
+                            acc.span(),
+                            e.span(),
+                            Completion(acc, e),
+                        )
+                    }
+                )
+            },
+        ))
+    }
+
     #[alias(expression, shortcut = true)]
     fn selector_expression(input: ParseInput) -> ParseResult<Expr> {
         Ok(match_nodes!(input.children();
diff --git a/dhall/src/syntax/text/printer.rs b/dhall/src/syntax/text/printer.rs
index dff3479..759e7e6 100644
--- a/dhall/src/syntax/text/printer.rs
+++ b/dhall/src/syntax/text/printer.rs
@@ -64,6 +64,7 @@ impl<E: Display + Clone> UnspannedExpr<E> {
             Field(a, b) => Field(a.phase(Primitive), b),
             Projection(e, ls) => Projection(e.phase(Primitive), ls),
             ProjectionByExpr(a, b) => ProjectionByExpr(a.phase(Primitive), b),
+            Completion(a, b) => Completion(a.phase(Primitive), b.phase(Primitive)),
             e => e,
         }
     }
@@ -89,7 +90,7 @@ impl<E: Display + Clone> UnspannedExpr<E> {
             // Precedence is magically handled by the ordering of BinOps.
             ExprKind::BinOp(op, _, _) => phase > PrintPhase::BinOp(*op),
             ExprKind::App(_, _) => phase > PrintPhase::App,
-            Field(_, _) | Projection(_, _) | ProjectionByExpr(_, _) => {
+            Field(_, _) | Projection(_, _) | ProjectionByExpr(_, _) | Completion(_, _) => {
                 phase > PrintPhase::Import
             }
             _ => false,
@@ -189,13 +190,6 @@ impl<SE: Display + Clone, E: Display> Display for ExprKind<SE, E> {
             Field(a, b) => {
                 write!(f, "{}.{}", a, b)?;
             }
-            Projection(e, ls) => {
-                write!(f, "{}.", e)?;
-                fmt_list("{ ", ", ", " }", ls, f, Display::fmt)?;
-            }
-            ProjectionByExpr(a, b) => {
-                write!(f, "{}.({})", a, b)?;
-            }
             Var(a) => a.fmt(f)?,
             Const(k) => k.fmt(f)?,
             Builtin(v) => v.fmt(f)?,
@@ -224,6 +218,16 @@ impl<SE: Display + Clone, E: Display> Display for ExprKind<SE, E> {
                 }
                 Ok(())
             })?,
+            Projection(e, ls) => {
+                write!(f, "{}.", e)?;
+                fmt_list("{ ", ", ", " }", ls, f, Display::fmt)?;
+            }
+            ProjectionByExpr(a, b) => {
+                write!(f, "{}.({})", a, b)?;
+            }
+            Completion(a, b) => {
+                write!(f, "{}::{}", a, b)?;
+            }
             Import(a) => a.fmt(f)?,
             Embed(a) => a.fmt(f)?,
         }
-- 
cgit v1.3.1


From 5536fe26187952a51087416ddd294d1da1ec689d Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Sun, 22 Dec 2019 19:14:29 +0000
Subject: rustfmt

---
 dhall/src/syntax/binary/encode.rs |  4 +---
 dhall/src/syntax/text/printer.rs  | 11 +++++++----
 2 files changed, 8 insertions(+), 7 deletions(-)

(limited to 'dhall/src')

diff --git a/dhall/src/syntax/binary/encode.rs b/dhall/src/syntax/binary/encode.rs
index 867fc9c..5e79f2d 100644
--- a/dhall/src/syntax/binary/encode.rs
+++ b/dhall/src/syntax/binary/encode.rs
@@ -164,9 +164,7 @@ where
         ProjectionByExpr(x, y) => {
             ser_seq!(ser; tag(10), expr(x), vec![expr(y)])
         }
-        Completion(x, y) => {
-            ser_seq!(ser; tag(3), tag(13), expr(x), expr(y))
-        }
+        Completion(x, y) => ser_seq!(ser; tag(3), tag(13), expr(x), expr(y)),
         Import(import) => serialize_import(ser, import),
         Embed(_) => unimplemented!(
             "An expression with resolved imports cannot be binary-encoded"
diff --git a/dhall/src/syntax/text/printer.rs b/dhall/src/syntax/text/printer.rs
index 759e7e6..626ab1c 100644
--- a/dhall/src/syntax/text/printer.rs
+++ b/dhall/src/syntax/text/printer.rs
@@ -64,7 +64,9 @@ impl<E: Display + Clone> UnspannedExpr<E> {
             Field(a, b) => Field(a.phase(Primitive), b),
             Projection(e, ls) => Projection(e.phase(Primitive), ls),
             ProjectionByExpr(a, b) => ProjectionByExpr(a.phase(Primitive), b),
-            Completion(a, b) => Completion(a.phase(Primitive), b.phase(Primitive)),
+            Completion(a, b) => {
+                Completion(a.phase(Primitive), b.phase(Primitive))
+            }
             e => e,
         }
     }
@@ -90,9 +92,10 @@ impl<E: Display + Clone> UnspannedExpr<E> {
             // Precedence is magically handled by the ordering of BinOps.
             ExprKind::BinOp(op, _, _) => phase > PrintPhase::BinOp(*op),
             ExprKind::App(_, _) => phase > PrintPhase::App,
-            Field(_, _) | Projection(_, _) | ProjectionByExpr(_, _) | Completion(_, _) => {
-                phase > PrintPhase::Import
-            }
+            Field(_, _)
+            | Projection(_, _)
+            | ProjectionByExpr(_, _)
+            | Completion(_, _) => phase > PrintPhase::Import,
             _ => false,
         };
 
-- 
cgit v1.3.1


From faccb680fbede2191e23161e7060be843bcc229e Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Sun, 22 Dec 2019 19:16:34 +0000
Subject: Update dhall-lang submodule

---
 dhall-lang                             |   2 +-
 dhall/src/semantics/phase/normalize.rs | 119 ++++++++++++---------------------
 2 files changed, 43 insertions(+), 78 deletions(-)

(limited to 'dhall/src')

diff --git a/dhall-lang b/dhall-lang
index 31e90e1..0ee92af 160000
--- a/dhall-lang
+++ b/dhall-lang
@@ -1 +1 @@
-Subproject commit 31e90e1996f6c4cb50e03ccb1f3c45beb4bd278c
+Subproject commit 0ee92af46a01a889c6d8d7c72926c959d034b19b
diff --git a/dhall/src/semantics/phase/normalize.rs b/dhall/src/semantics/phase/normalize.rs
index 65384c2..6258ae8 100644
--- a/dhall/src/semantics/phase/normalize.rs
+++ b/dhall/src/semantics/phase/normalize.rs
@@ -259,37 +259,23 @@ pub(crate) fn apply_builtin(
                 _ => Ret::DoneAsIs,
             }
         }
-        (ListBuild, [t, f]) => match &*f.as_whnf() {
-            // fold/build fusion
-            ValueKind::AppliedBuiltin(ListFold, args) => {
-                if args.len() >= 2 {
-                    Ret::Value(args[1].clone())
-                } else {
-                    // Do we really need to handle this case ?
-                    unimplemented!()
-                }
-            }
-            _ => {
-                let list_t = Value::from_builtin(List).app(t.clone());
-                Ret::Value(
-                    f.app(list_t.clone())
-                        .app({
-                            // Move `t` under new variables
-                            let t1 = t.under_binder(Label::from("x"));
-                            let t2 = t1.under_binder(Label::from("xs"));
-                            make_closure!(
-                                λ(x : #t) ->
-                                λ(xs : List #t1) ->
-                                [ var(x, 1, #t2) ] # var(xs, 0, List #t2)
-                            )
-                        })
-                        .app(
-                            EmptyListLit(t.clone())
-                                .into_value_with_type(list_t),
-                        ),
-                )
-            }
-        },
+        (ListBuild, [t, f]) => {
+            let list_t = Value::from_builtin(List).app(t.clone());
+            Ret::Value(
+                f.app(list_t.clone())
+                    .app({
+                        // Move `t` under new variables
+                        let t1 = t.under_binder(Label::from("x"));
+                        let t2 = t1.under_binder(Label::from("xs"));
+                        make_closure!(
+                            λ(x : #t) ->
+                            λ(xs : List #t1) ->
+                            [ var(x, 1, #t2) ] # var(xs, 0, List #t2)
+                        )
+                    })
+                    .app(EmptyListLit(t.clone()).into_value_with_type(list_t)),
+            )
+        }
         (ListFold, [_, l, _, cons, nil, r @ ..]) => match &*l.as_whnf() {
             EmptyListLit(_) => Ret::ValueWithRemainingArgs(r, nil.clone()),
             NEListLit(xs) => {
@@ -301,31 +287,20 @@ pub(crate) fn apply_builtin(
             }
             _ => Ret::DoneAsIs,
         },
-        (OptionalBuild, [t, f]) => match &*f.as_whnf() {
-            // fold/build fusion
-            ValueKind::AppliedBuiltin(OptionalFold, args) => {
-                if args.len() >= 2 {
-                    Ret::Value(args[1].clone())
-                } else {
-                    // Do we really need to handle this case ?
-                    unimplemented!()
-                }
-            }
-            _ => {
-                let optional_t = Value::from_builtin(Optional).app(t.clone());
-                Ret::Value(
-                    f.app(optional_t.clone())
-                        .app({
-                            let t1 = t.under_binder(Label::from("x"));
-                            make_closure!(λ(x: #t) -> Some(var(x, 0, #t1)))
-                        })
-                        .app(
-                            EmptyOptionalLit(t.clone())
-                                .into_value_with_type(optional_t),
-                        ),
-                )
-            }
-        },
+        (OptionalBuild, [t, f]) => {
+            let optional_t = Value::from_builtin(Optional).app(t.clone());
+            Ret::Value(
+                f.app(optional_t.clone())
+                    .app({
+                        let t1 = t.under_binder(Label::from("x"));
+                        make_closure!(λ(x: #t) -> Some(var(x, 0, #t1)))
+                    })
+                    .app(
+                        EmptyOptionalLit(t.clone())
+                            .into_value_with_type(optional_t),
+                    ),
+            )
+        }
         (OptionalFold, [_, v, _, just, nothing, r @ ..]) => match &*v.as_whnf()
         {
             EmptyOptionalLit(_) => {
@@ -336,27 +311,17 @@ pub(crate) fn apply_builtin(
             }
             _ => Ret::DoneAsIs,
         },
-        (NaturalBuild, [f]) => match &*f.as_whnf() {
-            // fold/build fusion
-            ValueKind::AppliedBuiltin(NaturalFold, args) => {
-                if !args.is_empty() {
-                    Ret::Value(args[0].clone())
-                } else {
-                    // Do we really need to handle this case ?
-                    unimplemented!()
-                }
-            }
-            _ => Ret::Value(
-                f.app(Value::from_builtin(Natural))
-                    .app(make_closure!(
-                        λ(x : Natural) -> 1 + var(x, 0, Natural)
-                    ))
-                    .app(
-                        NaturalLit(0)
-                            .into_value_with_type(Value::from_builtin(Natural)),
-                    ),
-            ),
-        },
+        (NaturalBuild, [f]) => Ret::Value(
+            f.app(Value::from_builtin(Natural))
+                .app(make_closure!(
+                    λ(x : Natural) -> 1 + var(x, 0, Natural)
+                ))
+                .app(
+                    NaturalLit(0)
+                        .into_value_with_type(Value::from_builtin(Natural)),
+                ),
+        ),
+
         (NaturalFold, [n, t, succ, zero, r @ ..]) => match &*n.as_whnf() {
             NaturalLit(0) => Ret::ValueWithRemainingArgs(r, zero.clone()),
             NaturalLit(n) => {
-- 
cgit v1.3.1


From 0e928ebde4ab8b662499eb716f366b97479c75fc Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Mon, 23 Dec 2019 21:59:47 +0000
Subject: Add two new Integer builtins

---
 dhall-lang                             |  2 +-
 dhall/src/semantics/phase/normalize.rs | 11 +++++++++++
 dhall/src/semantics/phase/typecheck.rs |  3 +++
 dhall/src/syntax/ast/expr.rs           |  2 ++
 dhall/src/syntax/text/parser.rs        |  2 ++
 dhall/src/syntax/text/printer.rs       |  2 ++
 6 files changed, 21 insertions(+), 1 deletion(-)

(limited to 'dhall/src')

diff --git a/dhall-lang b/dhall-lang
index 89bbf42..ee12030 160000
--- a/dhall-lang
+++ b/dhall-lang
@@ -1 +1 @@
-Subproject commit 89bbf42f9fd3e9e09f0a15aac9a23d309e50b155
+Subproject commit ee120309828f8a18b3267d192e3030add2a718e5
diff --git a/dhall/src/semantics/phase/normalize.rs b/dhall/src/semantics/phase/normalize.rs
index 6258ae8..5a0f566 100644
--- a/dhall/src/semantics/phase/normalize.rs
+++ b/dhall/src/semantics/phase/normalize.rs
@@ -1,4 +1,5 @@
 use std::collections::HashMap;
+use std::convert::TryInto;
 
 use crate::semantics::core::value::Value;
 use crate::semantics::core::value::ValueKind;
@@ -141,6 +142,16 @@ pub(crate) fn apply_builtin(
             }
             _ => Ret::DoneAsIs,
         },
+        (IntegerNegate, [n]) => match &*n.as_whnf() {
+            IntegerLit(n) => Ret::ValueKind(IntegerLit(-n)),
+            _ => Ret::DoneAsIs,
+        },
+        (IntegerClamp, [n]) => match &*n.as_whnf() {
+            IntegerLit(n) => {
+                Ret::ValueKind(NaturalLit((*n).try_into().unwrap_or(0)))
+            }
+            _ => Ret::DoneAsIs,
+        },
         (DoubleShow, [n]) => {
             match &*n.as_whnf() {
                 DoubleLit(n) => Ret::ValueKind(TextLit(vec![
diff --git a/dhall/src/semantics/phase/typecheck.rs b/dhall/src/semantics/phase/typecheck.rs
index c9834e1..7ea4951 100644
--- a/dhall/src/semantics/phase/typecheck.rs
+++ b/dhall/src/semantics/phase/typecheck.rs
@@ -235,6 +235,9 @@ fn type_of_builtin<E>(b: Builtin) -> Expr<E> {
 
         IntegerToDouble => make_type!(Integer -> Double),
         IntegerShow => make_type!(Integer -> Text),
+        IntegerNegate => make_type!(Integer -> Integer),
+        IntegerClamp => make_type!(Integer -> Natural),
+
         DoubleShow => make_type!(Double -> Text),
         TextShow => make_type!(Text -> Text),
 
diff --git a/dhall/src/syntax/ast/expr.rs b/dhall/src/syntax/ast/expr.rs
index fe49448..68cb524 100644
--- a/dhall/src/syntax/ast/expr.rs
+++ b/dhall/src/syntax/ast/expr.rs
@@ -79,6 +79,8 @@ pub enum Builtin {
     NaturalSubtract,
     IntegerToDouble,
     IntegerShow,
+    IntegerNegate,
+    IntegerClamp,
     DoubleShow,
     ListBuild,
     ListFold,
diff --git a/dhall/src/syntax/text/parser.rs b/dhall/src/syntax/text/parser.rs
index fe34aee..d9e5c3b 100644
--- a/dhall/src/syntax/text/parser.rs
+++ b/dhall/src/syntax/text/parser.rs
@@ -57,6 +57,8 @@ impl crate::syntax::Builtin {
             "Natural/subtract" => Some(NaturalSubtract),
             "Integer/toDouble" => Some(IntegerToDouble),
             "Integer/show" => Some(IntegerShow),
+            "Integer/negate" => Some(IntegerNegate),
+            "Integer/clamp" => Some(IntegerClamp),
             "Double/show" => Some(DoubleShow),
             "List/build" => Some(ListBuild),
             "List/fold" => Some(ListFold),
diff --git a/dhall/src/syntax/text/printer.rs b/dhall/src/syntax/text/printer.rs
index 626ab1c..96f4c2a 100644
--- a/dhall/src/syntax/text/printer.rs
+++ b/dhall/src/syntax/text/printer.rs
@@ -468,6 +468,8 @@ impl Display for Builtin {
             NaturalShow => "Natural/show",
             NaturalSubtract => "Natural/subtract",
             IntegerToDouble => "Integer/toDouble",
+            IntegerNegate => "Integer/negate",
+            IntegerClamp => "Integer/clamp",
             IntegerShow => "Integer/show",
             DoubleShow => "Double/show",
             ListBuild => "List/build",
-- 
cgit v1.3.1


From 4c7deccba50cb6d46134362128e3cb25c693c153 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Mon, 23 Dec 2019 22:30:27 +0000
Subject: Update dhall-lang submodule

---
 dhall-lang                      |  2 +-
 dhall/build.rs                  |  8 ++++++++
 dhall/src/dhall.pest.visibility |  4 ++++
 dhall/src/syntax/text/parser.rs | 23 ++++++++++-------------
 4 files changed, 23 insertions(+), 14 deletions(-)

(limited to 'dhall/src')

diff --git a/dhall-lang b/dhall-lang
index 3b31dea..464b735 160000
--- a/dhall-lang
+++ b/dhall-lang
@@ -1 +1 @@
-Subproject commit 3b31dea1ba47f9de041a7288826f07a05a167ba7
+Subproject commit 464b7358545a0d5c10d0aa987fed94bedc7f5162
diff --git a/dhall/build.rs b/dhall/build.rs
index 70389bf..981e558 100644
--- a/dhall/build.rs
+++ b/dhall/build.rs
@@ -414,12 +414,20 @@ fn convert_abnf_to_pest() -> std::io::Result<()> {
     rules.remove("url_path");
     writeln!(&mut file, "url_path = _{{ path }}")?;
 
+    // Work around some greediness issue in the grammar.
     rules.remove("missing");
     writeln!(
         &mut file,
         r#"missing = {{ "missing" ~ !simple_label_next_char }}"#
     )?;
 
+    // Prefer my nice error message to illegible parse errors.
+    rules.remove("unicode_escape");
+    writeln!(
+        &mut file,
+        r#"unicode_escape = _{{ HEXDIG{{4}} | "{{" ~ HEXDIG+ ~ "}}" }}"#
+    )?;
+
     rules.remove("simple_label");
     writeln!(
         &mut file,
diff --git a/dhall/src/dhall.pest.visibility b/dhall/src/dhall.pest.visibility
index 41aa833..5d3b4c8 100644
--- a/dhall/src/dhall.pest.visibility
+++ b/dhall/src/dhall.pest.visibility
@@ -24,6 +24,10 @@ quoted_label
 double_quote_chunk
 double_quote_escaped
 # unicode_escape
+# unicode_suffix
+# unbraced_escape
+# braced_codepoint
+# braced_escape
 double_quote_char
 double_quote_literal
 single_quote_continue
diff --git a/dhall/src/syntax/text/parser.rs b/dhall/src/syntax/text/parser.rs
index d9e5c3b..27e0382 100644
--- a/dhall/src/syntax/text/parser.rs
+++ b/dhall/src/syntax/text/parser.rs
@@ -217,19 +217,18 @@ impl DhallParser {
             "t" => "\t".to_owned(),
             // "uXXXX" or "u{XXXXX}"
             s => {
-                use std::convert::{TryFrom, TryInto};
+                use std::convert::TryInto;
 
                 let s = &s[1..];
                 let s = if &s[0..1] == "{" {
                     &s[1..s.len() - 1]
                 } else {
-                    &s[0..s.len()]
+                    s
                 };
 
                 if s.len() > 8 {
                     Err(input.error(format!(
-                        "Escape sequences can't have more than 8 chars: \"{}\"",
-                        s
+                        "Escape sequences can't have more than 8 chars"
                     )))?
                 }
 
@@ -242,12 +241,10 @@ impl DhallParser {
                 // `s` has length 8, so `bytes` has length 4
                 let bytes: &[u8] = &hex::decode(s).unwrap();
                 let i = u32::from_be_bytes(bytes.try_into().unwrap());
-                let c = char::try_from(i).unwrap();
                 match i {
-                    0xD800..=0xDFFF => {
-                        let c_ecapsed = c.escape_unicode();
-                        Err(input.error(format!("Escape sequences can't contain surrogate pairs: \"{}\"", c_ecapsed)))?
-                    }
+                    0xD800..=0xDFFF => Err(input.error(format!(
+                        "Escape sequences can't contain surrogate pairs"
+                    )))?,
                     0x0FFFE..=0x0FFFF
                     | 0x1FFFE..=0x1FFFF
                     | 0x2FFFE..=0x2FFFF
@@ -264,12 +261,12 @@ impl DhallParser {
                     | 0xDFFFE..=0xDFFFF
                     | 0xEFFFE..=0xEFFFF
                     | 0xFFFFE..=0xFFFFF
-                    | 0x10_FFFE..=0x10_FFFF => {
-                        let c_ecapsed = c.escape_unicode();
-                        Err(input.error(format!("Escape sequences can't contain non-characters: \"{}\"", c_ecapsed)))?
-                    }
+                    | 0x10_FFFE..=0x10_FFFF => Err(input.error(format!(
+                        "Escape sequences can't contain non-characters"
+                    )))?,
                     _ => {}
                 }
+                let c: char = i.try_into().unwrap();
                 std::iter::once(c).collect()
             }
         })
-- 
cgit v1.3.1


From 12d6a22c7dcdc0cb6e169b082b4553caec0e6027 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Mon, 23 Dec 2019 22:48:51 +0000
Subject: Update dhall-lang submodule

---
 dhall-lang                      |  2 +-
 dhall/src/syntax/text/parser.rs | 28 ++++++++++++++++++----------
 2 files changed, 19 insertions(+), 11 deletions(-)

(limited to 'dhall/src')

diff --git a/dhall-lang b/dhall-lang
index 9f24813..c7dd51e 160000
--- a/dhall-lang
+++ b/dhall-lang
@@ -1 +1 @@
-Subproject commit 9f248138f69ee5e22192dc3d0417d5c77b189e04
+Subproject commit c7dd51ec433e07433243cf1a1134655dbab6cc95
diff --git a/dhall/src/syntax/text/parser.rs b/dhall/src/syntax/text/parser.rs
index 27e0382..0e3e97a 100644
--- a/dhall/src/syntax/text/parser.rs
+++ b/dhall/src/syntax/text/parser.rs
@@ -383,19 +383,27 @@ impl DhallParser {
     }
 
     fn natural_literal(input: ParseInput) -> ParseResult<Natural> {
-        input
-            .as_str()
-            .trim()
-            .parse()
-            .map_err(|e| input.error(format!("{}", e)))
+        let s = input.as_str().trim();
+        if s.starts_with("0x") {
+            let without_prefix = s.trim_start_matches("0x");
+            usize::from_str_radix(without_prefix, 16)
+                .map_err(|e| input.error(format!("{}", e)))
+        } else {
+            s.parse().map_err(|e| input.error(format!("{}", e)))
+        }
     }
 
     fn integer_literal(input: ParseInput) -> ParseResult<Integer> {
-        input
-            .as_str()
-            .trim()
-            .parse()
-            .map_err(|e| input.error(format!("{}", e)))
+        let s = input.as_str().trim();
+        let (sign, rest) = (&s[0..1], &s[1..]);
+        if rest.starts_with("0x") {
+            let without_prefix =
+                sign.to_owned() + rest.trim_start_matches("0x");
+            isize::from_str_radix(&without_prefix, 16)
+                .map_err(|e| input.error(format!("{}", e)))
+        } else {
+            s.parse().map_err(|e| input.error(format!("{}", e)))
+        }
     }
 
     #[alias(expression, shortcut = true)]
-- 
cgit v1.3.1


From f22eb87b7a7aeccfa556dcdb56148e89cee023db Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Tue, 24 Dec 2019 18:10:12 +0000
Subject: Add debug output to unhandled type error message

---
 dhall/src/error/mod.rs                                                  | 2 +-
 dhall/tests/type-errors/mixedUnions.txt                                 | 2 +-
 dhall/tests/type-errors/recordOfKind.txt                                | 2 +-
 dhall/tests/type-errors/unit/AnnotationRecordWrongFieldName.txt         | 2 +-
 dhall/tests/type-errors/unit/AnnotationRecordWrongFieldType.txt         | 2 +-
 dhall/tests/type-errors/unit/AssertDoubleZeros.txt                      | 2 +-
 dhall/tests/type-errors/unit/AssertNotEquivalence.txt                   | 2 +-
 dhall/tests/type-errors/unit/AssertTriviallyFalse.txt                   | 2 +-
 dhall/tests/type-errors/unit/EquivalenceNotSameType.txt                 | 2 +-
 dhall/tests/type-errors/unit/EquivalenceNotTerms.txt                    | 2 +-
 dhall/tests/type-errors/unit/FunctionTypeKindSort.txt                   | 2 +-
 dhall/tests/type-errors/unit/FunctionTypeTypeSort.txt                   | 2 +-
 dhall/tests/type-errors/unit/IfBranchesNotMatch.txt                     | 2 +-
 dhall/tests/type-errors/unit/IfBranchesNotType.txt                      | 2 +-
 dhall/tests/type-errors/unit/IfNotBool.txt                              | 2 +-
 dhall/tests/type-errors/unit/LetWithWrongAnnotation.txt                 | 2 +-
 dhall/tests/type-errors/unit/ListLiteralNotType.txt                     | 2 +-
 dhall/tests/type-errors/unit/ListLiteralTypesNotMatch.txt               | 2 +-
 dhall/tests/type-errors/unit/MergeAlternativeHasNoHandler.txt           | 2 +-
 dhall/tests/type-errors/unit/MergeAnnotationMismatch.txt                | 2 +-
 dhall/tests/type-errors/unit/MergeAnnotationNotType.txt                 | 2 +-
 dhall/tests/type-errors/unit/MergeEmptyNeedsDirectAnnotation1.txt       | 2 +-
 dhall/tests/type-errors/unit/MergeEmptyNeedsDirectAnnotation2.txt       | 2 +-
 dhall/tests/type-errors/unit/MergeEmptyWithoutAnnotation.txt            | 2 +-
 dhall/tests/type-errors/unit/MergeHandlerFreeVar.txt                    | 2 +-
 dhall/tests/type-errors/unit/MergeHandlerNotInUnion.txt                 | 2 +-
 dhall/tests/type-errors/unit/MergeHandlersWithDifferentType.txt         | 2 +-
 dhall/tests/type-errors/unit/MergeLhsNotRecord.txt                      | 2 +-
 dhall/tests/type-errors/unit/MergeMissingHandler1.txt                   | 2 +-
 dhall/tests/type-errors/unit/MergeMissingHandler2.txt                   | 2 +-
 dhall/tests/type-errors/unit/MergeRhsNotUnion.txt                       | 2 +-
 dhall/tests/type-errors/unit/MergeUnusedHandler.txt                     | 2 +-
 dhall/tests/type-errors/unit/OperatorAndNotBool.txt                     | 2 +-
 dhall/tests/type-errors/unit/OperatorEqualNotBool.txt                   | 2 +-
 dhall/tests/type-errors/unit/OperatorListConcatenateLhsNotList.txt      | 2 +-
 dhall/tests/type-errors/unit/OperatorListConcatenateListsNotMatch.txt   | 2 +-
 .../tests/type-errors/unit/OperatorListConcatenateNotListsButMatch.txt  | 2 +-
 dhall/tests/type-errors/unit/OperatorListConcatenateRhsNotList.txt      | 2 +-
 dhall/tests/type-errors/unit/OperatorNotEqualNotBool.txt                | 2 +-
 dhall/tests/type-errors/unit/OperatorOrNotBool.txt                      | 2 +-
 dhall/tests/type-errors/unit/OperatorPlusNotNatural.txt                 | 2 +-
 dhall/tests/type-errors/unit/OperatorTextConcatenateLhsNotText.txt      | 2 +-
 dhall/tests/type-errors/unit/OperatorTextConcatenateRhsNotText.txt      | 2 +-
 dhall/tests/type-errors/unit/OperatorTimesNotNatural.txt                | 2 +-
 dhall/tests/type-errors/unit/OptionalDeprecatedSyntaxAbsent.txt         | 2 +-
 dhall/tests/type-errors/unit/OptionalDeprecatedSyntaxPresent.txt        | 2 +-
 dhall/tests/type-errors/unit/RecordLitDuplicateFields.txt               | 2 +-
 dhall/tests/type-errors/unit/RecordMixedKinds3.txt                      | 2 +-
 dhall/tests/type-errors/unit/RecordProjectionDuplicateFields.txt        | 2 +-
 dhall/tests/type-errors/unit/RecordProjectionEmpty.txt                  | 2 +-
 dhall/tests/type-errors/unit/RecordProjectionNotPresent.txt             | 2 +-
 dhall/tests/type-errors/unit/RecordProjectionNotRecord.txt              | 2 +-
 dhall/tests/type-errors/unit/RecordSelectionEmpty.txt                   | 2 +-
 dhall/tests/type-errors/unit/RecordSelectionNotPresent.txt              | 2 +-
 dhall/tests/type-errors/unit/RecordSelectionNotRecord.txt               | 2 +-
 dhall/tests/type-errors/unit/RecordSelectionTypeNotUnionType.txt        | 2 +-
 dhall/tests/type-errors/unit/RecordTypeDuplicateFields.txt              | 2 +-
 dhall/tests/type-errors/unit/RecordTypeValueMember.txt                  | 2 +-
 dhall/tests/type-errors/unit/RecursiveRecordMergeLhsNotRecord.txt       | 2 +-
 dhall/tests/type-errors/unit/RecursiveRecordMergeOverlapping.txt        | 2 +-
 dhall/tests/type-errors/unit/RecursiveRecordMergeRhsNotRecord.txt       | 2 +-
 .../tests/type-errors/unit/RecursiveRecordTypeMergeLhsNotRecordType.txt | 2 +-
 dhall/tests/type-errors/unit/RecursiveRecordTypeMergeOverlapping.txt    | 2 +-
 .../tests/type-errors/unit/RecursiveRecordTypeMergeRhsNotRecordType.txt | 2 +-
 dhall/tests/type-errors/unit/RightBiasedRecordMergeLhsNotRecord.txt     | 2 +-
 dhall/tests/type-errors/unit/RightBiasedRecordMergeMixedKinds2.txt      | 2 +-
 dhall/tests/type-errors/unit/RightBiasedRecordMergeMixedKinds3.txt      | 2 +-
 dhall/tests/type-errors/unit/RightBiasedRecordMergeRhsNotRecord.txt     | 2 +-
 dhall/tests/type-errors/unit/SomeNotType.txt                            | 2 +-
 dhall/tests/type-errors/unit/Sort.txt                                   | 2 +-
 dhall/tests/type-errors/unit/TextLiteralInterpolateNotText.txt          | 2 +-
 dhall/tests/type-errors/unit/TypeAnnotationWrong.txt                    | 2 +-
 dhall/tests/type-errors/unit/UnionConstructorFieldNotPresent.txt        | 2 +-
 dhall/tests/type-errors/unit/UnionTypeDuplicateVariants1.txt            | 2 +-
 dhall/tests/type-errors/unit/UnionTypeDuplicateVariants2.txt            | 2 +-
 dhall/tests/type-errors/unit/UnionTypeMixedKinds.txt                    | 2 +-
 dhall/tests/type-errors/unit/UnionTypeMixedKinds2.txt                   | 2 +-
 dhall/tests/type-errors/unit/UnionTypeMixedKinds3.txt                   | 2 +-
 dhall/tests/type-errors/unit/UnionTypeNotType.txt                       | 2 +-
 79 files changed, 79 insertions(+), 79 deletions(-)

(limited to 'dhall/src')

diff --git a/dhall/src/error/mod.rs b/dhall/src/error/mod.rs
index 40cccac..8976478 100644
--- a/dhall/src/error/mod.rs
+++ b/dhall/src/error/mod.rs
@@ -125,7 +125,7 @@ impl std::fmt::Display for TypeError {
                         y
                     ))
             }
-            _ => "Type error: Unhandled error".to_string(),
+            _ => format!("Type error: Unhandled error: {:?}", self.message),
         };
         write!(f, "{}", msg)
     }
diff --git a/dhall/tests/type-errors/mixedUnions.txt b/dhall/tests/type-errors/mixedUnions.txt
index 4b68fea..30fcdf8 100644
--- a/dhall/tests/type-errors/mixedUnions.txt
+++ b/dhall/tests/type-errors/mixedUnions.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: InvalidFieldType(Label("Right"), Type)
diff --git a/dhall/tests/type-errors/recordOfKind.txt b/dhall/tests/type-errors/recordOfKind.txt
index 4b68fea..5b88ff7 100644
--- a/dhall/tests/type-errors/recordOfKind.txt
+++ b/dhall/tests/type-errors/recordOfKind.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: Sort
diff --git a/dhall/tests/type-errors/unit/AnnotationRecordWrongFieldName.txt b/dhall/tests/type-errors/unit/AnnotationRecordWrongFieldName.txt
index 4b68fea..e15da48 100644
--- a/dhall/tests/type-errors/unit/AnnotationRecordWrongFieldName.txt
+++ b/dhall/tests/type-errors/unit/AnnotationRecordWrongFieldName.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: AnnotMismatch(Value@Unevaled { value: PartialExpr(RecordLit(DupTreeMap { map: {Label("x"): [Value@Unevaled { value: PartialExpr(NaturalLit(1)), type: Value@Unevaled { value: AppliedBuiltin(Natural, []), type: Type } }]}, size: 1 })), type: Value@WHNF { value: RecordType({Label("x"): Value@Unevaled { value: AppliedBuiltin(Natural, []), type: Type }}), type: Type } }, Value@WHNF { value: RecordType({Label("y"): Value@Unevaled { value: AppliedBuiltin(Natural, []), type: Type }}), type: Type })
diff --git a/dhall/tests/type-errors/unit/AnnotationRecordWrongFieldType.txt b/dhall/tests/type-errors/unit/AnnotationRecordWrongFieldType.txt
index 4b68fea..16b2d83 100644
--- a/dhall/tests/type-errors/unit/AnnotationRecordWrongFieldType.txt
+++ b/dhall/tests/type-errors/unit/AnnotationRecordWrongFieldType.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: AnnotMismatch(Value@Unevaled { value: PartialExpr(RecordLit(DupTreeMap { map: {Label("x"): [Value@Unevaled { value: PartialExpr(NaturalLit(1)), type: Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type } }]}, size: 1 })), type: Value@WHNF { value: RecordType({Label("x"): Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type }}), type: Type } }, Value@WHNF { value: RecordType({Label("x"): Value@WHNF { value: AppliedBuiltin(Text, []), type: Type }}), type: Type })
diff --git a/dhall/tests/type-errors/unit/AssertDoubleZeros.txt b/dhall/tests/type-errors/unit/AssertDoubleZeros.txt
index 4b68fea..d9df5c7 100644
--- a/dhall/tests/type-errors/unit/AssertDoubleZeros.txt
+++ b/dhall/tests/type-errors/unit/AssertDoubleZeros.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: AssertMismatch(Value@WHNF { value: DoubleLit(NaiveDouble(-0.0)), type: Value@WHNF { value: AppliedBuiltin(Double, []), type: Type } }, Value@WHNF { value: DoubleLit(NaiveDouble(0.0)), type: Value@WHNF { value: AppliedBuiltin(Double, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/AssertNotEquivalence.txt b/dhall/tests/type-errors/unit/AssertNotEquivalence.txt
index 4b68fea..537d31a 100644
--- a/dhall/tests/type-errors/unit/AssertNotEquivalence.txt
+++ b/dhall/tests/type-errors/unit/AssertNotEquivalence.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: AssertMustTakeEquivalence
diff --git a/dhall/tests/type-errors/unit/AssertTriviallyFalse.txt b/dhall/tests/type-errors/unit/AssertTriviallyFalse.txt
index 4b68fea..c7bbf8d 100644
--- a/dhall/tests/type-errors/unit/AssertTriviallyFalse.txt
+++ b/dhall/tests/type-errors/unit/AssertTriviallyFalse.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: AssertMismatch(Value@WHNF { value: NaturalLit(1), type: Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type } }, Value@WHNF { value: NaturalLit(2), type: Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/EquivalenceNotSameType.txt b/dhall/tests/type-errors/unit/EquivalenceNotSameType.txt
index 4b68fea..4dbe2ad 100644
--- a/dhall/tests/type-errors/unit/EquivalenceNotSameType.txt
+++ b/dhall/tests/type-errors/unit/EquivalenceNotSameType.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: EquivalenceTypeMismatch(Value@Unevaled { value: PartialExpr(BoolLit(false)), type: Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type } }, Value@Unevaled { value: PartialExpr(NaturalLit(1)), type: Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/EquivalenceNotTerms.txt b/dhall/tests/type-errors/unit/EquivalenceNotTerms.txt
index 4b68fea..dbce067 100644
--- a/dhall/tests/type-errors/unit/EquivalenceNotTerms.txt
+++ b/dhall/tests/type-errors/unit/EquivalenceNotTerms.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: EquivalenceArgumentMustBeTerm(true, Value@Unevaled { value: AppliedBuiltin(Bool, []), type: Type })
diff --git a/dhall/tests/type-errors/unit/FunctionTypeKindSort.txt b/dhall/tests/type-errors/unit/FunctionTypeKindSort.txt
index 4b68fea..5b88ff7 100644
--- a/dhall/tests/type-errors/unit/FunctionTypeKindSort.txt
+++ b/dhall/tests/type-errors/unit/FunctionTypeKindSort.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: Sort
diff --git a/dhall/tests/type-errors/unit/FunctionTypeTypeSort.txt b/dhall/tests/type-errors/unit/FunctionTypeTypeSort.txt
index 4b68fea..5b88ff7 100644
--- a/dhall/tests/type-errors/unit/FunctionTypeTypeSort.txt
+++ b/dhall/tests/type-errors/unit/FunctionTypeTypeSort.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: Sort
diff --git a/dhall/tests/type-errors/unit/IfBranchesNotMatch.txt b/dhall/tests/type-errors/unit/IfBranchesNotMatch.txt
index 4b68fea..262e54f 100644
--- a/dhall/tests/type-errors/unit/IfBranchesNotMatch.txt
+++ b/dhall/tests/type-errors/unit/IfBranchesNotMatch.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: IfBranchMismatch(Value@Unevaled { value: PartialExpr(NaturalLit(1)), type: Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type } }, Value@Unevaled { value: PartialExpr(TextLit(InterpolatedText { head: "", tail: [] })), type: Value@WHNF { value: AppliedBuiltin(Text, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/IfBranchesNotType.txt b/dhall/tests/type-errors/unit/IfBranchesNotType.txt
index 4b68fea..8ef3a40 100644
--- a/dhall/tests/type-errors/unit/IfBranchesNotType.txt
+++ b/dhall/tests/type-errors/unit/IfBranchesNotType.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: IfBranchMustBeTerm(true, Type)
diff --git a/dhall/tests/type-errors/unit/IfNotBool.txt b/dhall/tests/type-errors/unit/IfNotBool.txt
index 4b68fea..64c0465 100644
--- a/dhall/tests/type-errors/unit/IfNotBool.txt
+++ b/dhall/tests/type-errors/unit/IfNotBool.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: InvalidPredicate(Value@Unevaled { value: PartialExpr(NaturalLit(1)), type: Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/LetWithWrongAnnotation.txt b/dhall/tests/type-errors/unit/LetWithWrongAnnotation.txt
index 4b68fea..0862162 100644
--- a/dhall/tests/type-errors/unit/LetWithWrongAnnotation.txt
+++ b/dhall/tests/type-errors/unit/LetWithWrongAnnotation.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: AnnotMismatch(Value@Unevaled { value: PartialExpr(BoolLit(true)), type: Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type } }, Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type })
diff --git a/dhall/tests/type-errors/unit/ListLiteralNotType.txt b/dhall/tests/type-errors/unit/ListLiteralNotType.txt
index 4b68fea..99b95a3 100644
--- a/dhall/tests/type-errors/unit/ListLiteralNotType.txt
+++ b/dhall/tests/type-errors/unit/ListLiteralNotType.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: InvalidListType(Type)
diff --git a/dhall/tests/type-errors/unit/ListLiteralTypesNotMatch.txt b/dhall/tests/type-errors/unit/ListLiteralTypesNotMatch.txt
index 4b68fea..7916dbb 100644
--- a/dhall/tests/type-errors/unit/ListLiteralTypesNotMatch.txt
+++ b/dhall/tests/type-errors/unit/ListLiteralTypesNotMatch.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: InvalidListElement(1, Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type }, Value@Unevaled { value: PartialExpr(NaturalLit(1)), type: Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/MergeAlternativeHasNoHandler.txt b/dhall/tests/type-errors/unit/MergeAlternativeHasNoHandler.txt
index 4b68fea..d4e9024 100644
--- a/dhall/tests/type-errors/unit/MergeAlternativeHasNoHandler.txt
+++ b/dhall/tests/type-errors/unit/MergeAlternativeHasNoHandler.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: MergeVariantMissingHandler(Label("x"))
diff --git a/dhall/tests/type-errors/unit/MergeAnnotationMismatch.txt b/dhall/tests/type-errors/unit/MergeAnnotationMismatch.txt
index 4b68fea..823f2f7 100644
--- a/dhall/tests/type-errors/unit/MergeAnnotationMismatch.txt
+++ b/dhall/tests/type-errors/unit/MergeAnnotationMismatch.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: MergeAnnotMismatch
diff --git a/dhall/tests/type-errors/unit/MergeAnnotationNotType.txt b/dhall/tests/type-errors/unit/MergeAnnotationNotType.txt
index 4b68fea..852634a 100644
--- a/dhall/tests/type-errors/unit/MergeAnnotationNotType.txt
+++ b/dhall/tests/type-errors/unit/MergeAnnotationNotType.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: Merge2ArgMustBeUnion(Value@Unevaled { value: UnionType({}), type: Type })
diff --git a/dhall/tests/type-errors/unit/MergeEmptyNeedsDirectAnnotation1.txt b/dhall/tests/type-errors/unit/MergeEmptyNeedsDirectAnnotation1.txt
index 4b68fea..563b3bf 100644
--- a/dhall/tests/type-errors/unit/MergeEmptyNeedsDirectAnnotation1.txt
+++ b/dhall/tests/type-errors/unit/MergeEmptyNeedsDirectAnnotation1.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: MergeEmptyNeedsAnnotation
diff --git a/dhall/tests/type-errors/unit/MergeEmptyNeedsDirectAnnotation2.txt b/dhall/tests/type-errors/unit/MergeEmptyNeedsDirectAnnotation2.txt
index 4b68fea..563b3bf 100644
--- a/dhall/tests/type-errors/unit/MergeEmptyNeedsDirectAnnotation2.txt
+++ b/dhall/tests/type-errors/unit/MergeEmptyNeedsDirectAnnotation2.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: MergeEmptyNeedsAnnotation
diff --git a/dhall/tests/type-errors/unit/MergeEmptyWithoutAnnotation.txt b/dhall/tests/type-errors/unit/MergeEmptyWithoutAnnotation.txt
index 4b68fea..852634a 100644
--- a/dhall/tests/type-errors/unit/MergeEmptyWithoutAnnotation.txt
+++ b/dhall/tests/type-errors/unit/MergeEmptyWithoutAnnotation.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: Merge2ArgMustBeUnion(Value@Unevaled { value: UnionType({}), type: Type })
diff --git a/dhall/tests/type-errors/unit/MergeHandlerFreeVar.txt b/dhall/tests/type-errors/unit/MergeHandlerFreeVar.txt
index 4b68fea..de9e256 100644
--- a/dhall/tests/type-errors/unit/MergeHandlerFreeVar.txt
+++ b/dhall/tests/type-errors/unit/MergeHandlerFreeVar.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: MergeHandlerReturnTypeMustNotBeDependent
diff --git a/dhall/tests/type-errors/unit/MergeHandlerNotInUnion.txt b/dhall/tests/type-errors/unit/MergeHandlerNotInUnion.txt
index 4b68fea..852634a 100644
--- a/dhall/tests/type-errors/unit/MergeHandlerNotInUnion.txt
+++ b/dhall/tests/type-errors/unit/MergeHandlerNotInUnion.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: Merge2ArgMustBeUnion(Value@Unevaled { value: UnionType({}), type: Type })
diff --git a/dhall/tests/type-errors/unit/MergeHandlersWithDifferentType.txt b/dhall/tests/type-errors/unit/MergeHandlersWithDifferentType.txt
index 4b68fea..8b729a4 100644
--- a/dhall/tests/type-errors/unit/MergeHandlersWithDifferentType.txt
+++ b/dhall/tests/type-errors/unit/MergeHandlersWithDifferentType.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: MergeHandlerTypeMismatch
diff --git a/dhall/tests/type-errors/unit/MergeLhsNotRecord.txt b/dhall/tests/type-errors/unit/MergeLhsNotRecord.txt
index 4b68fea..da600de 100644
--- a/dhall/tests/type-errors/unit/MergeLhsNotRecord.txt
+++ b/dhall/tests/type-errors/unit/MergeLhsNotRecord.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: Merge1ArgMustBeRecord(Value@Unevaled { value: PartialExpr(BoolLit(true)), type: Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/MergeMissingHandler1.txt b/dhall/tests/type-errors/unit/MergeMissingHandler1.txt
index 4b68fea..d4e9024 100644
--- a/dhall/tests/type-errors/unit/MergeMissingHandler1.txt
+++ b/dhall/tests/type-errors/unit/MergeMissingHandler1.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: MergeVariantMissingHandler(Label("x"))
diff --git a/dhall/tests/type-errors/unit/MergeMissingHandler2.txt b/dhall/tests/type-errors/unit/MergeMissingHandler2.txt
index 4b68fea..d583de7 100644
--- a/dhall/tests/type-errors/unit/MergeMissingHandler2.txt
+++ b/dhall/tests/type-errors/unit/MergeMissingHandler2.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: MergeVariantMissingHandler(Label("y"))
diff --git a/dhall/tests/type-errors/unit/MergeRhsNotUnion.txt b/dhall/tests/type-errors/unit/MergeRhsNotUnion.txt
index 4b68fea..0872642 100644
--- a/dhall/tests/type-errors/unit/MergeRhsNotUnion.txt
+++ b/dhall/tests/type-errors/unit/MergeRhsNotUnion.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: Merge2ArgMustBeUnion(Value@Unevaled { value: PartialExpr(BoolLit(true)), type: Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/MergeUnusedHandler.txt b/dhall/tests/type-errors/unit/MergeUnusedHandler.txt
index 4b68fea..b7eefdd 100644
--- a/dhall/tests/type-errors/unit/MergeUnusedHandler.txt
+++ b/dhall/tests/type-errors/unit/MergeUnusedHandler.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: MergeHandlerMissingVariant(Label("y"))
diff --git a/dhall/tests/type-errors/unit/OperatorAndNotBool.txt b/dhall/tests/type-errors/unit/OperatorAndNotBool.txt
index 4b68fea..a4346f2 100644
--- a/dhall/tests/type-errors/unit/OperatorAndNotBool.txt
+++ b/dhall/tests/type-errors/unit/OperatorAndNotBool.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: BinOpTypeMismatch(BoolAnd, Value@Unevaled { value: PartialExpr(NaturalLit(1)), type: Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/OperatorEqualNotBool.txt b/dhall/tests/type-errors/unit/OperatorEqualNotBool.txt
index 4b68fea..57f9095 100644
--- a/dhall/tests/type-errors/unit/OperatorEqualNotBool.txt
+++ b/dhall/tests/type-errors/unit/OperatorEqualNotBool.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: BinOpTypeMismatch(BoolEQ, Value@Unevaled { value: PartialExpr(NaturalLit(1)), type: Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/OperatorListConcatenateLhsNotList.txt b/dhall/tests/type-errors/unit/OperatorListConcatenateLhsNotList.txt
index 4b68fea..2bcb4fc 100644
--- a/dhall/tests/type-errors/unit/OperatorListConcatenateLhsNotList.txt
+++ b/dhall/tests/type-errors/unit/OperatorListConcatenateLhsNotList.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: BinOpTypeMismatch(ListAppend, Value@Unevaled { value: PartialExpr(NaturalLit(1)), type: Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/OperatorListConcatenateListsNotMatch.txt b/dhall/tests/type-errors/unit/OperatorListConcatenateListsNotMatch.txt
index 4b68fea..e314702 100644
--- a/dhall/tests/type-errors/unit/OperatorListConcatenateListsNotMatch.txt
+++ b/dhall/tests/type-errors/unit/OperatorListConcatenateListsNotMatch.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: BinOpTypeMismatch(ListAppend, Value@Unevaled { value: PartialExpr(NEListLit([Value@Unevaled { value: PartialExpr(NaturalLit(1)), type: Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type } }])), type: Value@WHNF { value: AppliedBuiltin(List, [Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type }]), type: Type } })
diff --git a/dhall/tests/type-errors/unit/OperatorListConcatenateNotListsButMatch.txt b/dhall/tests/type-errors/unit/OperatorListConcatenateNotListsButMatch.txt
index 4b68fea..2bcb4fc 100644
--- a/dhall/tests/type-errors/unit/OperatorListConcatenateNotListsButMatch.txt
+++ b/dhall/tests/type-errors/unit/OperatorListConcatenateNotListsButMatch.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: BinOpTypeMismatch(ListAppend, Value@Unevaled { value: PartialExpr(NaturalLit(1)), type: Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/OperatorListConcatenateRhsNotList.txt b/dhall/tests/type-errors/unit/OperatorListConcatenateRhsNotList.txt
index 4b68fea..2bcb4fc 100644
--- a/dhall/tests/type-errors/unit/OperatorListConcatenateRhsNotList.txt
+++ b/dhall/tests/type-errors/unit/OperatorListConcatenateRhsNotList.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: BinOpTypeMismatch(ListAppend, Value@Unevaled { value: PartialExpr(NaturalLit(1)), type: Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/OperatorNotEqualNotBool.txt b/dhall/tests/type-errors/unit/OperatorNotEqualNotBool.txt
index 4b68fea..32b3549 100644
--- a/dhall/tests/type-errors/unit/OperatorNotEqualNotBool.txt
+++ b/dhall/tests/type-errors/unit/OperatorNotEqualNotBool.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: BinOpTypeMismatch(BoolNE, Value@Unevaled { value: PartialExpr(NaturalLit(1)), type: Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/OperatorOrNotBool.txt b/dhall/tests/type-errors/unit/OperatorOrNotBool.txt
index 4b68fea..f91bd83 100644
--- a/dhall/tests/type-errors/unit/OperatorOrNotBool.txt
+++ b/dhall/tests/type-errors/unit/OperatorOrNotBool.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: BinOpTypeMismatch(BoolOr, Value@Unevaled { value: PartialExpr(NaturalLit(1)), type: Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/OperatorPlusNotNatural.txt b/dhall/tests/type-errors/unit/OperatorPlusNotNatural.txt
index 4b68fea..9194f3a 100644
--- a/dhall/tests/type-errors/unit/OperatorPlusNotNatural.txt
+++ b/dhall/tests/type-errors/unit/OperatorPlusNotNatural.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: BinOpTypeMismatch(NaturalPlus, Value@Unevaled { value: PartialExpr(BoolLit(true)), type: Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/OperatorTextConcatenateLhsNotText.txt b/dhall/tests/type-errors/unit/OperatorTextConcatenateLhsNotText.txt
index 4b68fea..e67e9e5 100644
--- a/dhall/tests/type-errors/unit/OperatorTextConcatenateLhsNotText.txt
+++ b/dhall/tests/type-errors/unit/OperatorTextConcatenateLhsNotText.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: BinOpTypeMismatch(TextAppend, Value@Unevaled { value: PartialExpr(NaturalLit(1)), type: Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/OperatorTextConcatenateRhsNotText.txt b/dhall/tests/type-errors/unit/OperatorTextConcatenateRhsNotText.txt
index 4b68fea..e67e9e5 100644
--- a/dhall/tests/type-errors/unit/OperatorTextConcatenateRhsNotText.txt
+++ b/dhall/tests/type-errors/unit/OperatorTextConcatenateRhsNotText.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: BinOpTypeMismatch(TextAppend, Value@Unevaled { value: PartialExpr(NaturalLit(1)), type: Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/OperatorTimesNotNatural.txt b/dhall/tests/type-errors/unit/OperatorTimesNotNatural.txt
index 4b68fea..8146ba9 100644
--- a/dhall/tests/type-errors/unit/OperatorTimesNotNatural.txt
+++ b/dhall/tests/type-errors/unit/OperatorTimesNotNatural.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: BinOpTypeMismatch(NaturalTimes, Value@Unevaled { value: PartialExpr(BoolLit(true)), type: Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/OptionalDeprecatedSyntaxAbsent.txt b/dhall/tests/type-errors/unit/OptionalDeprecatedSyntaxAbsent.txt
index 4b68fea..c319c81 100644
--- a/dhall/tests/type-errors/unit/OptionalDeprecatedSyntaxAbsent.txt
+++ b/dhall/tests/type-errors/unit/OptionalDeprecatedSyntaxAbsent.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: InvalidListType(Value@WHNF { value: AppliedBuiltin(Optional, [Value@Unevaled { value: AppliedBuiltin(Bool, []), type: Type }]), type: Type })
diff --git a/dhall/tests/type-errors/unit/OptionalDeprecatedSyntaxPresent.txt b/dhall/tests/type-errors/unit/OptionalDeprecatedSyntaxPresent.txt
index 4b68fea..99df27c 100644
--- a/dhall/tests/type-errors/unit/OptionalDeprecatedSyntaxPresent.txt
+++ b/dhall/tests/type-errors/unit/OptionalDeprecatedSyntaxPresent.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: AnnotMismatch(Value@Unevaled { value: PartialExpr(NEListLit([Value@Unevaled { value: PartialExpr(NaturalLit(1)), type: Value@Unevaled { value: AppliedBuiltin(Natural, []), type: Type } }])), type: Value@WHNF { value: AppliedBuiltin(List, [Value@Unevaled { value: AppliedBuiltin(Natural, []), type: Type }]), type: Type } }, Value@WHNF { value: AppliedBuiltin(Optional, [Value@Unevaled { value: AppliedBuiltin(Natural, []), type: Type }]), type: Type })
diff --git a/dhall/tests/type-errors/unit/RecordLitDuplicateFields.txt b/dhall/tests/type-errors/unit/RecordLitDuplicateFields.txt
index 4b68fea..4fc4a50 100644
--- a/dhall/tests/type-errors/unit/RecordLitDuplicateFields.txt
+++ b/dhall/tests/type-errors/unit/RecordLitDuplicateFields.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: RecordTypeDuplicateField
diff --git a/dhall/tests/type-errors/unit/RecordMixedKinds3.txt b/dhall/tests/type-errors/unit/RecordMixedKinds3.txt
index 4b68fea..5b88ff7 100644
--- a/dhall/tests/type-errors/unit/RecordMixedKinds3.txt
+++ b/dhall/tests/type-errors/unit/RecordMixedKinds3.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: Sort
diff --git a/dhall/tests/type-errors/unit/RecordProjectionDuplicateFields.txt b/dhall/tests/type-errors/unit/RecordProjectionDuplicateFields.txt
index 4b68fea..0d2e83e 100644
--- a/dhall/tests/type-errors/unit/RecordProjectionDuplicateFields.txt
+++ b/dhall/tests/type-errors/unit/RecordProjectionDuplicateFields.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: ProjectionDuplicateField
diff --git a/dhall/tests/type-errors/unit/RecordProjectionEmpty.txt b/dhall/tests/type-errors/unit/RecordProjectionEmpty.txt
index 4b68fea..ddbe5e4 100644
--- a/dhall/tests/type-errors/unit/RecordProjectionEmpty.txt
+++ b/dhall/tests/type-errors/unit/RecordProjectionEmpty.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: ProjectionMissingEntry
diff --git a/dhall/tests/type-errors/unit/RecordProjectionNotPresent.txt b/dhall/tests/type-errors/unit/RecordProjectionNotPresent.txt
index 4b68fea..ddbe5e4 100644
--- a/dhall/tests/type-errors/unit/RecordProjectionNotPresent.txt
+++ b/dhall/tests/type-errors/unit/RecordProjectionNotPresent.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: ProjectionMissingEntry
diff --git a/dhall/tests/type-errors/unit/RecordProjectionNotRecord.txt b/dhall/tests/type-errors/unit/RecordProjectionNotRecord.txt
index 4b68fea..cb4b52f 100644
--- a/dhall/tests/type-errors/unit/RecordProjectionNotRecord.txt
+++ b/dhall/tests/type-errors/unit/RecordProjectionNotRecord.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: ProjectionMustBeRecord
diff --git a/dhall/tests/type-errors/unit/RecordSelectionEmpty.txt b/dhall/tests/type-errors/unit/RecordSelectionEmpty.txt
index 4b68fea..1770faa 100644
--- a/dhall/tests/type-errors/unit/RecordSelectionEmpty.txt
+++ b/dhall/tests/type-errors/unit/RecordSelectionEmpty.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: MissingRecordField(Label("x"), Value@Unevaled { value: PartialExpr(RecordLit(DupTreeMap { map: {}, size: 0 })), type: Value@WHNF { value: RecordType({}), type: Type } })
diff --git a/dhall/tests/type-errors/unit/RecordSelectionNotPresent.txt b/dhall/tests/type-errors/unit/RecordSelectionNotPresent.txt
index 4b68fea..9211e05 100644
--- a/dhall/tests/type-errors/unit/RecordSelectionNotPresent.txt
+++ b/dhall/tests/type-errors/unit/RecordSelectionNotPresent.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: MissingRecordField(Label("x"), Value@Unevaled { value: PartialExpr(RecordLit(DupTreeMap { map: {Label("y"): [Value@Unevaled { value: PartialExpr(RecordLit(DupTreeMap { map: {}, size: 0 })), type: Value@Unevaled { value: RecordType({}), type: Type } }]}, size: 1 })), type: Value@WHNF { value: RecordType({Label("y"): Value@Unevaled { value: RecordType({}), type: Type }}), type: Type } })
diff --git a/dhall/tests/type-errors/unit/RecordSelectionNotRecord.txt b/dhall/tests/type-errors/unit/RecordSelectionNotRecord.txt
index 4b68fea..27db6a2 100644
--- a/dhall/tests/type-errors/unit/RecordSelectionNotRecord.txt
+++ b/dhall/tests/type-errors/unit/RecordSelectionNotRecord.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: NotARecord(Label("x"), Value@WHNF { value: BoolLit(true), type: Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/RecordSelectionTypeNotUnionType.txt b/dhall/tests/type-errors/unit/RecordSelectionTypeNotUnionType.txt
index 4b68fea..36c8e28 100644
--- a/dhall/tests/type-errors/unit/RecordSelectionTypeNotUnionType.txt
+++ b/dhall/tests/type-errors/unit/RecordSelectionTypeNotUnionType.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: NotARecord(Label("x"), Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type })
diff --git a/dhall/tests/type-errors/unit/RecordTypeDuplicateFields.txt b/dhall/tests/type-errors/unit/RecordTypeDuplicateFields.txt
index 4b68fea..4fc4a50 100644
--- a/dhall/tests/type-errors/unit/RecordTypeDuplicateFields.txt
+++ b/dhall/tests/type-errors/unit/RecordTypeDuplicateFields.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: RecordTypeDuplicateField
diff --git a/dhall/tests/type-errors/unit/RecordTypeValueMember.txt b/dhall/tests/type-errors/unit/RecordTypeValueMember.txt
index 4b68fea..72d4316 100644
--- a/dhall/tests/type-errors/unit/RecordTypeValueMember.txt
+++ b/dhall/tests/type-errors/unit/RecordTypeValueMember.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: InvalidFieldType(Label("x"), Value@Unevaled { value: PartialExpr(BoolLit(true)), type: Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/RecursiveRecordMergeLhsNotRecord.txt b/dhall/tests/type-errors/unit/RecursiveRecordMergeLhsNotRecord.txt
index 4b68fea..42cdf65 100644
--- a/dhall/tests/type-errors/unit/RecursiveRecordMergeLhsNotRecord.txt
+++ b/dhall/tests/type-errors/unit/RecursiveRecordMergeLhsNotRecord.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: RecordTypeMergeRequiresRecordType(Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type })
diff --git a/dhall/tests/type-errors/unit/RecursiveRecordMergeOverlapping.txt b/dhall/tests/type-errors/unit/RecursiveRecordMergeOverlapping.txt
index 4b68fea..42cdf65 100644
--- a/dhall/tests/type-errors/unit/RecursiveRecordMergeOverlapping.txt
+++ b/dhall/tests/type-errors/unit/RecursiveRecordMergeOverlapping.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: RecordTypeMergeRequiresRecordType(Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type })
diff --git a/dhall/tests/type-errors/unit/RecursiveRecordMergeRhsNotRecord.txt b/dhall/tests/type-errors/unit/RecursiveRecordMergeRhsNotRecord.txt
index 4b68fea..42cdf65 100644
--- a/dhall/tests/type-errors/unit/RecursiveRecordMergeRhsNotRecord.txt
+++ b/dhall/tests/type-errors/unit/RecursiveRecordMergeRhsNotRecord.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: RecordTypeMergeRequiresRecordType(Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type })
diff --git a/dhall/tests/type-errors/unit/RecursiveRecordTypeMergeLhsNotRecordType.txt b/dhall/tests/type-errors/unit/RecursiveRecordTypeMergeLhsNotRecordType.txt
index 4b68fea..42cdf65 100644
--- a/dhall/tests/type-errors/unit/RecursiveRecordTypeMergeLhsNotRecordType.txt
+++ b/dhall/tests/type-errors/unit/RecursiveRecordTypeMergeLhsNotRecordType.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: RecordTypeMergeRequiresRecordType(Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type })
diff --git a/dhall/tests/type-errors/unit/RecursiveRecordTypeMergeOverlapping.txt b/dhall/tests/type-errors/unit/RecursiveRecordTypeMergeOverlapping.txt
index 4b68fea..42cdf65 100644
--- a/dhall/tests/type-errors/unit/RecursiveRecordTypeMergeOverlapping.txt
+++ b/dhall/tests/type-errors/unit/RecursiveRecordTypeMergeOverlapping.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: RecordTypeMergeRequiresRecordType(Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type })
diff --git a/dhall/tests/type-errors/unit/RecursiveRecordTypeMergeRhsNotRecordType.txt b/dhall/tests/type-errors/unit/RecursiveRecordTypeMergeRhsNotRecordType.txt
index 4b68fea..42cdf65 100644
--- a/dhall/tests/type-errors/unit/RecursiveRecordTypeMergeRhsNotRecordType.txt
+++ b/dhall/tests/type-errors/unit/RecursiveRecordTypeMergeRhsNotRecordType.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: RecordTypeMergeRequiresRecordType(Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type })
diff --git a/dhall/tests/type-errors/unit/RightBiasedRecordMergeLhsNotRecord.txt b/dhall/tests/type-errors/unit/RightBiasedRecordMergeLhsNotRecord.txt
index 4b68fea..9a2913b 100644
--- a/dhall/tests/type-errors/unit/RightBiasedRecordMergeLhsNotRecord.txt
+++ b/dhall/tests/type-errors/unit/RightBiasedRecordMergeLhsNotRecord.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: MustCombineRecord(Value@Unevaled { value: PartialExpr(BoolLit(true)), type: Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/RightBiasedRecordMergeMixedKinds2.txt b/dhall/tests/type-errors/unit/RightBiasedRecordMergeMixedKinds2.txt
index 4b68fea..5b88ff7 100644
--- a/dhall/tests/type-errors/unit/RightBiasedRecordMergeMixedKinds2.txt
+++ b/dhall/tests/type-errors/unit/RightBiasedRecordMergeMixedKinds2.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: Sort
diff --git a/dhall/tests/type-errors/unit/RightBiasedRecordMergeMixedKinds3.txt b/dhall/tests/type-errors/unit/RightBiasedRecordMergeMixedKinds3.txt
index 4b68fea..5b88ff7 100644
--- a/dhall/tests/type-errors/unit/RightBiasedRecordMergeMixedKinds3.txt
+++ b/dhall/tests/type-errors/unit/RightBiasedRecordMergeMixedKinds3.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: Sort
diff --git a/dhall/tests/type-errors/unit/RightBiasedRecordMergeRhsNotRecord.txt b/dhall/tests/type-errors/unit/RightBiasedRecordMergeRhsNotRecord.txt
index 4b68fea..9a2913b 100644
--- a/dhall/tests/type-errors/unit/RightBiasedRecordMergeRhsNotRecord.txt
+++ b/dhall/tests/type-errors/unit/RightBiasedRecordMergeRhsNotRecord.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: MustCombineRecord(Value@Unevaled { value: PartialExpr(BoolLit(true)), type: Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/SomeNotType.txt b/dhall/tests/type-errors/unit/SomeNotType.txt
index 4b68fea..43581a0 100644
--- a/dhall/tests/type-errors/unit/SomeNotType.txt
+++ b/dhall/tests/type-errors/unit/SomeNotType.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: InvalidOptionalType(Type)
diff --git a/dhall/tests/type-errors/unit/Sort.txt b/dhall/tests/type-errors/unit/Sort.txt
index 4b68fea..5b88ff7 100644
--- a/dhall/tests/type-errors/unit/Sort.txt
+++ b/dhall/tests/type-errors/unit/Sort.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: Sort
diff --git a/dhall/tests/type-errors/unit/TextLiteralInterpolateNotText.txt b/dhall/tests/type-errors/unit/TextLiteralInterpolateNotText.txt
index 4b68fea..ba2aecd 100644
--- a/dhall/tests/type-errors/unit/TextLiteralInterpolateNotText.txt
+++ b/dhall/tests/type-errors/unit/TextLiteralInterpolateNotText.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: InvalidTextInterpolation(Value@Unevaled { value: PartialExpr(NaturalLit(1)), type: Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type } })
diff --git a/dhall/tests/type-errors/unit/TypeAnnotationWrong.txt b/dhall/tests/type-errors/unit/TypeAnnotationWrong.txt
index 4b68fea..77ff57f 100644
--- a/dhall/tests/type-errors/unit/TypeAnnotationWrong.txt
+++ b/dhall/tests/type-errors/unit/TypeAnnotationWrong.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: AnnotMismatch(Value@Unevaled { value: PartialExpr(NaturalLit(1)), type: Value@WHNF { value: AppliedBuiltin(Natural, []), type: Type } }, Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type })
diff --git a/dhall/tests/type-errors/unit/UnionConstructorFieldNotPresent.txt b/dhall/tests/type-errors/unit/UnionConstructorFieldNotPresent.txt
index 4b68fea..7b2e610 100644
--- a/dhall/tests/type-errors/unit/UnionConstructorFieldNotPresent.txt
+++ b/dhall/tests/type-errors/unit/UnionConstructorFieldNotPresent.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: MissingUnionField(Label("y"), Value@WHNF { value: UnionType({Label("x"): Some(Value@Unevaled { value: AppliedBuiltin(Bool, []), type: Type })}), type: Type })
diff --git a/dhall/tests/type-errors/unit/UnionTypeDuplicateVariants1.txt b/dhall/tests/type-errors/unit/UnionTypeDuplicateVariants1.txt
index 4b68fea..27c6cbe 100644
--- a/dhall/tests/type-errors/unit/UnionTypeDuplicateVariants1.txt
+++ b/dhall/tests/type-errors/unit/UnionTypeDuplicateVariants1.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: UnionTypeDuplicateField
diff --git a/dhall/tests/type-errors/unit/UnionTypeDuplicateVariants2.txt b/dhall/tests/type-errors/unit/UnionTypeDuplicateVariants2.txt
index 4b68fea..27c6cbe 100644
--- a/dhall/tests/type-errors/unit/UnionTypeDuplicateVariants2.txt
+++ b/dhall/tests/type-errors/unit/UnionTypeDuplicateVariants2.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: UnionTypeDuplicateField
diff --git a/dhall/tests/type-errors/unit/UnionTypeMixedKinds.txt b/dhall/tests/type-errors/unit/UnionTypeMixedKinds.txt
index 4b68fea..07604ba 100644
--- a/dhall/tests/type-errors/unit/UnionTypeMixedKinds.txt
+++ b/dhall/tests/type-errors/unit/UnionTypeMixedKinds.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: InvalidFieldType(Label("y"), Type)
diff --git a/dhall/tests/type-errors/unit/UnionTypeMixedKinds2.txt b/dhall/tests/type-errors/unit/UnionTypeMixedKinds2.txt
index 4b68fea..07604ba 100644
--- a/dhall/tests/type-errors/unit/UnionTypeMixedKinds2.txt
+++ b/dhall/tests/type-errors/unit/UnionTypeMixedKinds2.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: InvalidFieldType(Label("y"), Type)
diff --git a/dhall/tests/type-errors/unit/UnionTypeMixedKinds3.txt b/dhall/tests/type-errors/unit/UnionTypeMixedKinds3.txt
index 4b68fea..83fc426 100644
--- a/dhall/tests/type-errors/unit/UnionTypeMixedKinds3.txt
+++ b/dhall/tests/type-errors/unit/UnionTypeMixedKinds3.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: InvalidFieldType(Label("y"), Value@Unevaled { value: AppliedBuiltin(Bool, []), type: Type })
diff --git a/dhall/tests/type-errors/unit/UnionTypeNotType.txt b/dhall/tests/type-errors/unit/UnionTypeNotType.txt
index 4b68fea..72d4316 100644
--- a/dhall/tests/type-errors/unit/UnionTypeNotType.txt
+++ b/dhall/tests/type-errors/unit/UnionTypeNotType.txt
@@ -1 +1 @@
-Type error: Unhandled error
+Type error: Unhandled error: InvalidFieldType(Label("x"), Value@Unevaled { value: PartialExpr(BoolLit(true)), type: Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type } })
-- 
cgit v1.3.1


From 5f52c5bda0277edd87323eb67dcda721cd18a9d3 Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Tue, 24 Dec 2019 20:23:19 +0000
Subject: Extend merge to work on Optionals

---
 dhall-lang                                         |  2 +-
 dhall/build.rs                                     | 16 ++++++++++++---
 dhall/src/dhall.pest.visibility                    |  1 +
 dhall/src/error/mod.rs                             |  2 +-
 dhall/src/semantics/phase/normalize.rs             | 24 ++++++++++++++++++++--
 dhall/src/semantics/phase/typecheck.rs             | 16 +++++++++++++--
 dhall/src/syntax/text/parser.rs                    |  9 ++++++++
 .../type-errors/unit/MergeAnnotationNotType.txt    |  2 +-
 .../unit/MergeEmptyWithoutAnnotation.txt           |  2 +-
 .../type-errors/unit/MergeHandlerNotInUnion.txt    |  2 +-
 dhall/tests/type-errors/unit/MergeRhsNotUnion.txt  |  2 +-
 11 files changed, 65 insertions(+), 13 deletions(-)

(limited to 'dhall/src')

diff --git a/dhall-lang b/dhall-lang
index c7dd51e..0c99dc6 160000
--- a/dhall-lang
+++ b/dhall-lang
@@ -1 +1 @@
-Subproject commit c7dd51ec433e07433243cf1a1134655dbab6cc95
+Subproject commit 0c99dc6f53919fc2df6b965877c355b62cf6ba02
diff --git a/dhall/build.rs b/dhall/build.rs
index 981e558..3d4a2eb 100644
--- a/dhall/build.rs
+++ b/dhall/build.rs
@@ -128,7 +128,7 @@ fn generate_tests() -> std::io::Result<()> {
                     || path == "unit/import/urls/emptyPath0"
                     || path == "unit/import/urls/emptyPath1"
                     || path == "unit/import/urls/emptyPathSegment"
-                    // TODO: https://github.com/dhall-lang/dhall-lang/pull/788#issuecomment-568298973
+                    // TODO: waiting for https://github.com/dhall-lang/dhall-lang/pull/871
                     || path == "preferMissingNoSpaces"
             }),
             input_type: FileType::Text,
@@ -154,7 +154,7 @@ fn generate_tests() -> std::io::Result<()> {
                     || path == "unit/import/urls/emptyPath0"
                     || path == "unit/import/urls/emptyPath1"
                     || path == "unit/import/urls/emptyPathSegment"
-                    // TODO: https://github.com/dhall-lang/dhall-lang/pull/788#issuecomment-568298973
+                    // TODO: waiting for https://github.com/dhall-lang/dhall-lang/pull/871
                     || path == "preferMissingNoSpaces"
             }),
             input_type: FileType::Text,
@@ -178,7 +178,7 @@ fn generate_tests() -> std::io::Result<()> {
                     || path == "unit/import/urls/emptyPath0"
                     || path == "unit/import/urls/emptyPath1"
                     || path == "unit/import/urls/emptyPathSegment"
-                    // TODO: https://github.com/dhall-lang/dhall-lang/pull/788#issuecomment-568298973
+                    // TODO: waiting for https://github.com/dhall-lang/dhall-lang/pull/871
                     || path == "preferMissingNoSpaces"
             }),
             input_type: FileType::Text,
@@ -282,6 +282,9 @@ fn generate_tests() -> std::io::Result<()> {
                     // TODO: record completion
                     || path == "simple/completion"
                     || path == "unit/Completion"
+                    // TODO: waiting for https://github.com/dhall-lang/dhall-lang/pull/871
+                    || path == "unit/MergeNone"
+                    || path == "unit/MergeSome"
             }),
             input_type: FileType::Text,
             output_type: Some(FileType::Text),
@@ -317,6 +320,9 @@ fn generate_tests() -> std::io::Result<()> {
                     // TODO: record completion
                     || path == "simple/completion"
                     || path == "unit/Completion"
+                    // TODO: waiting for https://github.com/dhall-lang/dhall-lang/pull/871
+                    || path == "unit/MergeNone"
+                    || path == "unit/MergeSome"
             }),
             input_type: FileType::Text,
             output_type: Some(FileType::Text),
@@ -423,6 +429,10 @@ fn convert_abnf_to_pest() -> std::io::Result<()> {
 
     // Prefer my nice error message to illegible parse errors.
     rules.remove("unicode_escape");
+    rules.remove("unbraced_escape");
+    rules.remove("braced_escape");
+    rules.remove("braced_codepoint");
+    rules.remove("unicode_suffix");
     writeln!(
         &mut file,
         r#"unicode_escape = _{{ HEXDIG{{4}} | "{{" ~ HEXDIG+ ~ "}}" }}"#
diff --git a/dhall/src/dhall.pest.visibility b/dhall/src/dhall.pest.visibility
index 5d3b4c8..03a000b 100644
--- a/dhall/src/dhall.pest.visibility
+++ b/dhall/src/dhall.pest.visibility
@@ -21,6 +21,7 @@ quoted_label
 # label
 # nonreserved_label
 # any_label
+any_label_or_some
 double_quote_chunk
 double_quote_escaped
 # unicode_escape
diff --git a/dhall/src/error/mod.rs b/dhall/src/error/mod.rs
index 8976478..6e7be64 100644
--- a/dhall/src/error/mod.rs
+++ b/dhall/src/error/mod.rs
@@ -67,7 +67,7 @@ pub(crate) enum TypeMessage {
     BinOpTypeMismatch(BinOp, Value),
     InvalidTextInterpolation(Value),
     Merge1ArgMustBeRecord(Value),
-    Merge2ArgMustBeUnion(Value),
+    Merge2ArgMustBeUnionOrOptional(Value),
     MergeEmptyNeedsAnnotation,
     MergeHandlerMissingVariant(Label),
     MergeVariantMissingHandler(Label),
diff --git a/dhall/src/semantics/phase/normalize.rs b/dhall/src/semantics/phase/normalize.rs
index 5a0f566..459eaf1 100644
--- a/dhall/src/semantics/phase/normalize.rs
+++ b/dhall/src/semantics/phase/normalize.rs
@@ -590,8 +590,8 @@ pub(crate) fn normalize_one_layer(
     ty: &Value,
 ) -> ValueKind {
     use ValueKind::{
-        AppliedBuiltin, BoolLit, DoubleLit, EmptyListLit, IntegerLit,
-        NEListLit, NEOptionalLit, NaturalLit, RecordLit, TextLit,
+        AppliedBuiltin, BoolLit, DoubleLit, EmptyListLit, EmptyOptionalLit,
+        IntegerLit, NEListLit, NEOptionalLit, NaturalLit, RecordLit, TextLit,
         UnionConstructor, UnionLit, UnionType,
     };
 
@@ -739,6 +739,26 @@ pub(crate) fn normalize_one_layer(
                         Ret::Expr(expr)
                     }
                 },
+                (RecordLit(kvs), EmptyOptionalLit(_)) => {
+                    match kvs.get(&"None".into()) {
+                        Some(h) => Ret::Value(h.clone()),
+                        None => {
+                            drop(handlers_borrow);
+                            drop(variant_borrow);
+                            Ret::Expr(expr)
+                        }
+                    }
+                }
+                (RecordLit(kvs), NEOptionalLit(v)) => {
+                    match kvs.get(&"Some".into()) {
+                        Some(h) => Ret::Value(h.app(v.clone())),
+                        None => {
+                            drop(handlers_borrow);
+                            drop(variant_borrow);
+                            Ret::Expr(expr)
+                        }
+                    }
+                }
                 _ => {
                     drop(handlers_borrow);
                     drop(variant_borrow);
diff --git a/dhall/src/semantics/phase/typecheck.rs b/dhall/src/semantics/phase/typecheck.rs
index 7ea4951..97502d4 100644
--- a/dhall/src/semantics/phase/typecheck.rs
+++ b/dhall/src/semantics/phase/typecheck.rs
@@ -1,3 +1,4 @@
+use std::borrow::Cow;
 use std::cmp::max;
 use std::collections::HashMap;
 
@@ -695,8 +696,19 @@ fn type_last_layer(
             let union_type = union.get_type()?;
             let union_borrow = union_type.as_whnf();
             let variants = match &*union_borrow {
-                ValueKind::UnionType(kts) => kts,
-                _ => return mkerr(Merge2ArgMustBeUnion(union.clone())),
+                ValueKind::UnionType(kts) => Cow::Borrowed(kts),
+                ValueKind::AppliedBuiltin(syntax::Builtin::Optional, args)
+                    if args.len() == 1 =>
+                {
+                    let ty = &args[0];
+                    let mut kts = HashMap::new();
+                    kts.insert("None".into(), None);
+                    kts.insert("Some".into(), Some(ty.clone()));
+                    Cow::Owned(kts)
+                }
+                _ => {
+                    return mkerr(Merge2ArgMustBeUnionOrOptional(union.clone()))
+                }
             };
 
             let mut inferred_type = None;
diff --git a/dhall/src/syntax/text/parser.rs b/dhall/src/syntax/text/parser.rs
index 0e3e97a..feaa2a5 100644
--- a/dhall/src/syntax/text/parser.rs
+++ b/dhall/src/syntax/text/parser.rs
@@ -183,6 +183,15 @@ impl DhallParser {
         Ok(Label::from(input.as_str()))
     }
 
+    // TODO: waiting for https://github.com/dhall-lang/dhall-lang/pull/871
+    // #[alias(label)]
+    // fn any_label_or_some(input: ParseInput) -> ParseResult<Label> {
+    //     Ok(match_nodes!(input.into_children();
+    //         [label(l)] => l,
+    //         [Some_(_)] => Label::from("Some"),
+    //     ))
+    // }
+
     fn double_quote_literal(input: ParseInput) -> ParseResult<ParsedText> {
         Ok(match_nodes!(input.into_children();
             [double_quote_chunk(chunks)..] => {
diff --git a/dhall/tests/type-errors/unit/MergeAnnotationNotType.txt b/dhall/tests/type-errors/unit/MergeAnnotationNotType.txt
index 852634a..7da5cb9 100644
--- a/dhall/tests/type-errors/unit/MergeAnnotationNotType.txt
+++ b/dhall/tests/type-errors/unit/MergeAnnotationNotType.txt
@@ -1 +1 @@
-Type error: Unhandled error: Merge2ArgMustBeUnion(Value@Unevaled { value: UnionType({}), type: Type })
+Type error: Unhandled error: Merge2ArgMustBeUnionOrOptional(Value@Unevaled { value: UnionType({}), type: Type })
diff --git a/dhall/tests/type-errors/unit/MergeEmptyWithoutAnnotation.txt b/dhall/tests/type-errors/unit/MergeEmptyWithoutAnnotation.txt
index 852634a..7da5cb9 100644
--- a/dhall/tests/type-errors/unit/MergeEmptyWithoutAnnotation.txt
+++ b/dhall/tests/type-errors/unit/MergeEmptyWithoutAnnotation.txt
@@ -1 +1 @@
-Type error: Unhandled error: Merge2ArgMustBeUnion(Value@Unevaled { value: UnionType({}), type: Type })
+Type error: Unhandled error: Merge2ArgMustBeUnionOrOptional(Value@Unevaled { value: UnionType({}), type: Type })
diff --git a/dhall/tests/type-errors/unit/MergeHandlerNotInUnion.txt b/dhall/tests/type-errors/unit/MergeHandlerNotInUnion.txt
index 852634a..7da5cb9 100644
--- a/dhall/tests/type-errors/unit/MergeHandlerNotInUnion.txt
+++ b/dhall/tests/type-errors/unit/MergeHandlerNotInUnion.txt
@@ -1 +1 @@
-Type error: Unhandled error: Merge2ArgMustBeUnion(Value@Unevaled { value: UnionType({}), type: Type })
+Type error: Unhandled error: Merge2ArgMustBeUnionOrOptional(Value@Unevaled { value: UnionType({}), type: Type })
diff --git a/dhall/tests/type-errors/unit/MergeRhsNotUnion.txt b/dhall/tests/type-errors/unit/MergeRhsNotUnion.txt
index 0872642..db93650 100644
--- a/dhall/tests/type-errors/unit/MergeRhsNotUnion.txt
+++ b/dhall/tests/type-errors/unit/MergeRhsNotUnion.txt
@@ -1 +1 @@
-Type error: Unhandled error: Merge2ArgMustBeUnion(Value@Unevaled { value: PartialExpr(BoolLit(true)), type: Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type } })
+Type error: Unhandled error: Merge2ArgMustBeUnionOrOptional(Value@Unevaled { value: PartialExpr(BoolLit(true)), type: Value@WHNF { value: AppliedBuiltin(Bool, []), type: Type } })
-- 
cgit v1.3.1