Consolidate errors in the error module

36 files changed, 169 insertions, 60 deletions

diff --git a/dhall/src/error.rs b/dhall/src/error.rs
deleted file mode 100644
index 8497a91..0000000
--- a/dhall/src/error.rs
+++ /dev/null
@@ -1,60 +0,0 @@
-use std::io::Error as IOError;
-
-use dhall_syntax::ParseError;
-
-use crate::phase::binary::DecodeError;
-use crate::phase::resolve::ImportError;
-use crate::phase::typecheck::TypeError;
-
-pub type Result<T> = std::result::Result<T, Error>;
-
-#[derive(Debug)]
-#[non_exhaustive]
-pub enum Error {
-    IO(IOError),
-    Parse(ParseError),
-    Decode(DecodeError),
-    Resolve(ImportError),
-    Typecheck(TypeError),
-    Deserialize(String),
-}
-
-impl std::fmt::Display for Error {
-    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
-        match self {
-            Error::IO(err) => write!(f, "{}", err),
-            Error::Parse(err) => write!(f, "{}", err),
-            Error::Decode(err) => write!(f, "{:?}", err),
-            Error::Resolve(err) => write!(f, "{:?}", err),
-            Error::Typecheck(err) => write!(f, "{:?}", err),
-            Error::Deserialize(err) => write!(f, "{}", err),
-        }
-    }
-}
-
-impl std::error::Error for Error {}
-impl From<IOError> for Error {
-    fn from(err: IOError) -> Error {
-        Error::IO(err)
-    }
-}
-impl From<ParseError> for Error {
-    fn from(err: ParseError) -> Error {
-        Error::Parse(err)
-    }
-}
-impl From<DecodeError> for Error {
-    fn from(err: DecodeError) -> Error {
-        Error::Decode(err)
-    }
-}
-impl From<ImportError> for Error {
-    fn from(err: ImportError) -> Error {
-        Error::Resolve(err)
-    }
-}
-impl From<TypeError> for Error {
-    fn from(err: TypeError) -> Error {
-        Error::Typecheck(err)
-    }
-}
diff --git a/dhall/src/error/mod.rs b/dhall/src/error/mod.rs
new file mode 100644
index 0000000..e70b9a9
--- /dev/null
+++ b/dhall/src/error/mod.rs
@@ -0,0 +1,169 @@
+use std::io::Error as IOError;
+
+use dhall_syntax::{BinOp, Import, Label, ParseError, V};
+
+use crate::phase::resolve::ImportStack;
+use crate::phase::typecheck::TypecheckContext;
+use crate::phase::{Normalized, Type, Typed};
+
+pub type Result<T> = std::result::Result<T, Error>;
+
+#[derive(Debug)]
+#[non_exhaustive]
+pub enum Error {
+    IO(IOError),
+    Parse(ParseError),
+    Decode(DecodeError),
+    Resolve(ImportError),
+    Typecheck(TypeError),
+    Deserialize(String),
+}
+
+#[derive(Debug)]
+pub enum ImportError {
+    Recursive(Import, Box<Error>),
+    UnexpectedImport(Import),
+    ImportCycle(ImportStack, Import),
+}
+
+#[derive(Debug)]
+pub enum DecodeError {
+    CBORError(serde_cbor::error::Error),
+    WrongFormatError(String),
+}
+
+/// A structured type error that includes context
+#[derive(Debug)]
+pub struct TypeError {
+    type_message: TypeMessage,
+    context: TypecheckContext,
+}
+
+/// The specific type error
+#[derive(Debug)]
+pub(crate) enum TypeMessage {
+    UnboundVariable(V<Label>),
+    InvalidInputType(Normalized),
+    InvalidOutputType(Normalized),
+    NotAFunction(Typed),
+    TypeMismatch(Typed, Normalized, Typed),
+    AnnotMismatch(Typed, Normalized),
+    Untyped,
+    InvalidListElement(usize, Normalized, Typed),
+    InvalidListType(Normalized),
+    InvalidOptionalType(Normalized),
+    InvalidPredicate(Typed),
+    IfBranchMismatch(Typed, Typed),
+    IfBranchMustBeTerm(bool, Typed),
+    InvalidFieldType(Label, Type),
+    NotARecord(Label, Normalized),
+    MissingRecordField(Label, Typed),
+    MissingUnionField(Label, Normalized),
+    BinOpTypeMismatch(BinOp, Typed),
+    NoDependentTypes(Normalized, Normalized),
+    InvalidTextInterpolation(Typed),
+    Sort,
+    Unimplemented,
+}
+
+impl TypeError {
+    pub(crate) fn new(
+        context: &TypecheckContext,
+        type_message: TypeMessage,
+    ) -> Self {
+        TypeError {
+            context: context.clone(),
+            type_message,
+        }
+    }
+}
+
+impl From<TypeError> for std::option::NoneError {
+    fn from(_: TypeError) -> std::option::NoneError {
+        std::option::NoneError
+    }
+}
+
+impl std::error::Error for TypeMessage {
+    fn description(&self) -> &str {
+        use TypeMessage::*;
+        match *self {
+            // UnboundVariable => "Unbound variable",
+            InvalidInputType(_) => "Invalid function input",
+            InvalidOutputType(_) => "Invalid function output",
+            NotAFunction(_) => "Not a function",
+            TypeMismatch(_, _, _) => "Wrong type of function argument",
+            _ => "Unhandled error",
+        }
+    }
+}
+
+impl std::fmt::Display for TypeMessage {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        match self {
+            // UnboundVariable(_) => {
+            //     f.write_str(include_str!("errors/UnboundVariable.txt"))
+            // }
+            // TypeMismatch(e0, e1, e2) => {
+            //     let template = include_str!("errors/TypeMismatch.txt");
+            //     let s = template
+            //         .replace("$txt0", &format!("{}", e0.as_expr()))
+            //         .replace("$txt1", &format!("{}", e1.as_expr()))
+            //         .replace("$txt2", &format!("{}", e2.as_expr()))
+            //         .replace(
+            //             "$txt3",
+            //             &format!(
+            //                 "{}",
+            //                 e2.get_type()
+            //                     .unwrap()
+            //                     .as_normalized()
+            //                     .unwrap()
+            //                     .as_expr()
+            //             ),
+            //         );
+            //     f.write_str(&s)
+            // }
+            _ => f.write_str("Unhandled error message"),
+        }
+    }
+}
+
+impl std::fmt::Display for Error {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        match self {
+            Error::IO(err) => write!(f, "{}", err),
+            Error::Parse(err) => write!(f, "{}", err),
+            Error::Decode(err) => write!(f, "{:?}", err),
+            Error::Resolve(err) => write!(f, "{:?}", err),
+            Error::Typecheck(err) => write!(f, "{:?}", err),
+            Error::Deserialize(err) => write!(f, "{}", err),
+        }
+    }
+}
+
+impl std::error::Error for Error {}
+impl From<IOError> for Error {
+    fn from(err: IOError) -> Error {
+        Error::IO(err)
+    }
+}
+impl From<ParseError> for Error {
+    fn from(err: ParseError) -> Error {
+        Error::Parse(err)
+    }
+}
+impl From<DecodeError> for Error {
+    fn from(err: DecodeError) -> Error {
+        Error::Decode(err)
+    }
+}
+impl From<ImportError> for Error {
+    fn from(err: ImportError) -> Error {
+        Error::Resolve(err)
+    }
+}
+impl From<TypeError> for Error {
+    fn from(err: TypeError) -> Error {
+        Error::Typecheck(err)
+    }
+}
diff --git a/dhall/src/errors/AnnotMismatch.txt b/dhall/src/error/text/AnnotMismatch.txt
index 4904bf8..4904bf8 100644
--- a/dhall/src/errors/AnnotMismatch.txt
+++ b/dhall/src/error/text/AnnotMismatch.txt
diff --git a/dhall/src/errors/CantTextAppend.txt b/dhall/src/error/text/CantTextAppend.txt
index 26b9ceb..26b9ceb 100644
--- a/dhall/src/errors/CantTextAppend.txt
+++ b/dhall/src/error/text/CantTextAppend.txt
diff --git a/dhall/src/errors/DuplicateAlternative.txt b/dhall/src/error/text/DuplicateAlternative.txt
index 077f8aa..077f8aa 100644
--- a/dhall/src/errors/DuplicateAlternative.txt
+++ b/dhall/src/error/text/DuplicateAlternative.txt
diff --git a/dhall/src/errors/FieldCollision.txt b/dhall/src/error/text/FieldCollision.txt
index 2b2d260..2b2d260 100644
--- a/dhall/src/errors/FieldCollision.txt
+++ b/dhall/src/error/text/FieldCollision.txt
diff --git a/dhall/src/errors/HandlerInputTypeMismatch.txt b/dhall/src/error/text/HandlerInputTypeMismatch.txt
index 7d3525b..7d3525b 100644
--- a/dhall/src/errors/HandlerInputTypeMismatch.txt
+++ b/dhall/src/error/text/HandlerInputTypeMismatch.txt
diff --git a/dhall/src/errors/HandlerNotAFunction.txt b/dhall/src/error/text/HandlerNotAFunction.txt
index ff87443..ff87443 100644
--- a/dhall/src/errors/HandlerNotAFunction.txt
+++ b/dhall/src/error/text/HandlerNotAFunction.txt
diff --git a/dhall/src/errors/HandlerOutputTypeMismatch.txt b/dhall/src/error/text/HandlerOutputTypeMismatch.txt
index f359459..f359459 100644
--- a/dhall/src/errors/HandlerOutputTypeMismatch.txt
+++ b/dhall/src/error/text/HandlerOutputTypeMismatch.txt
diff --git a/dhall/src/errors/IfBranchMismatch.txt b/dhall/src/error/text/IfBranchMismatch.txt
index a95b130..a95b130 100644
--- a/dhall/src/errors/IfBranchMismatch.txt
+++ b/dhall/src/error/text/IfBranchMismatch.txt
diff --git a/dhall/src/errors/IfBranchMustBeTerm.txt b/dhall/src/error/text/IfBranchMustBeTerm.txt
index 4c15881..4c15881 100644
--- a/dhall/src/errors/IfBranchMustBeTerm.txt
+++ b/dhall/src/error/text/IfBranchMustBeTerm.txt
diff --git a/dhall/src/errors/InvalidAlterantive.txt b/dhall/src/error/text/InvalidAlterantive.txt
index 391fc3a..391fc3a 100644
--- a/dhall/src/errors/InvalidAlterantive.txt
+++ b/dhall/src/error/text/InvalidAlterantive.txt
diff --git a/dhall/src/errors/InvalidAlterantiveType.txt b/dhall/src/error/text/InvalidAlterantiveType.txt
index f5dadef..f5dadef 100644
--- a/dhall/src/errors/InvalidAlterantiveType.txt
+++ b/dhall/src/error/text/InvalidAlterantiveType.txt
diff --git a/dhall/src/errors/InvalidField.txt b/dhall/src/error/text/InvalidField.txt
index bfbf106..bfbf106 100644
--- a/dhall/src/errors/InvalidField.txt
+++ b/dhall/src/error/text/InvalidField.txt
diff --git a/dhall/src/errors/InvalidFieldType.txt b/dhall/src/error/text/InvalidFieldType.txt
index 4f76a64..4f76a64 100644
--- a/dhall/src/errors/InvalidFieldType.txt
+++ b/dhall/src/error/text/InvalidFieldType.txt
diff --git a/dhall/src/errors/InvalidInputType.txt b/dhall/src/error/text/InvalidInputType.txt
index eabafa4..eabafa4 100644
--- a/dhall/src/errors/InvalidInputType.txt
+++ b/dhall/src/error/text/InvalidInputType.txt
diff --git a/dhall/src/errors/InvalidListElement.txt b/dhall/src/error/text/InvalidListElement.txt
index 59db7b7..59db7b7 100644
--- a/dhall/src/errors/InvalidListElement.txt
+++ b/dhall/src/error/text/InvalidListElement.txt
diff --git a/dhall/src/errors/InvalidListType.txt b/dhall/src/error/text/InvalidListType.txt
index 676647e..676647e 100644
--- a/dhall/src/errors/InvalidListType.txt
+++ b/dhall/src/error/text/InvalidListType.txt
diff --git a/dhall/src/errors/InvalidOptionType.txt b/dhall/src/error/text/InvalidOptionType.txt
index 3bc81de..3bc81de 100644
--- a/dhall/src/errors/InvalidOptionType.txt
+++ b/dhall/src/error/text/InvalidOptionType.txt
diff --git a/dhall/src/errors/InvalidOptionalElement.txt b/dhall/src/error/text/InvalidOptionalElement.txt
index 0254220..0254220 100644
--- a/dhall/src/errors/InvalidOptionalElement.txt
+++ b/dhall/src/error/text/InvalidOptionalElement.txt
diff --git a/dhall/src/errors/InvalidOptionalLiteral.txt b/dhall/src/error/text/InvalidOptionalLiteral.txt
index 41c0fdc..41c0fdc 100644
--- a/dhall/src/errors/InvalidOptionalLiteral.txt
+++ b/dhall/src/error/text/InvalidOptionalLiteral.txt
diff --git a/dhall/src/errors/InvalidOutputType.txt b/dhall/src/error/text/InvalidOutputType.txt
index dd2695d..dd2695d 100644
--- a/dhall/src/errors/InvalidOutputType.txt
+++ b/dhall/src/error/text/InvalidOutputType.txt
diff --git a/dhall/src/errors/InvalidPredicate.txt b/dhall/src/error/text/InvalidPredicate.txt
index 4c15881..4c15881 100644
--- a/dhall/src/errors/InvalidPredicate.txt
+++ b/dhall/src/error/text/InvalidPredicate.txt
diff --git a/dhall/src/errors/MissingField.txt b/dhall/src/error/text/MissingField.txt
index de14a33..de14a33 100644
--- a/dhall/src/errors/MissingField.txt
+++ b/dhall/src/error/text/MissingField.txt
diff --git a/dhall/src/errors/MissingHandler.txt b/dhall/src/error/text/MissingHandler.txt
index 433445e..433445e 100644
--- a/dhall/src/errors/MissingHandler.txt
+++ b/dhall/src/error/text/MissingHandler.txt
diff --git a/dhall/src/errors/MustCombineARecord.txt b/dhall/src/error/text/MustCombineARecord.txt
index 141b969..141b969 100644
--- a/dhall/src/errors/MustCombineARecord.txt
+++ b/dhall/src/error/text/MustCombineARecord.txt
diff --git a/dhall/src/errors/MustMergeARecord.txt b/dhall/src/error/text/MustMergeARecord.txt
index 79094bd..79094bd 100644
--- a/dhall/src/errors/MustMergeARecord.txt
+++ b/dhall/src/error/text/MustMergeARecord.txt
diff --git a/dhall/src/errors/MustMergeUnion.txt b/dhall/src/error/text/MustMergeUnion.txt
index 68df70c..68df70c 100644
--- a/dhall/src/errors/MustMergeUnion.txt
+++ b/dhall/src/error/text/MustMergeUnion.txt
diff --git a/dhall/src/errors/NoDependentLet.txt b/dhall/src/error/text/NoDependentLet.txt
index fdc65b4..fdc65b4 100644
--- a/dhall/src/errors/NoDependentLet.txt
+++ b/dhall/src/error/text/NoDependentLet.txt
diff --git a/dhall/src/errors/NoDependentTypes.txt b/dhall/src/error/text/NoDependentTypes.txt
index 435bdcb..435bdcb 100644
--- a/dhall/src/errors/NoDependentTypes.txt
+++ b/dhall/src/error/text/NoDependentTypes.txt
diff --git a/dhall/src/errors/NotAFunction.txt b/dhall/src/error/text/NotAFunction.txt
index dd2695d..dd2695d 100644
--- a/dhall/src/errors/NotAFunction.txt
+++ b/dhall/src/error/text/NotAFunction.txt
diff --git a/dhall/src/errors/NotARecord.txt b/dhall/src/error/text/NotARecord.txt
index e0eebc8..e0eebc8 100644
--- a/dhall/src/errors/NotARecord.txt
+++ b/dhall/src/error/text/NotARecord.txt
diff --git a/dhall/src/errors/TypeMismatch.txt b/dhall/src/error/text/TypeMismatch.txt
index 4904bf8..4904bf8 100644
--- a/dhall/src/errors/TypeMismatch.txt
+++ b/dhall/src/error/text/TypeMismatch.txt
diff --git a/dhall/src/errors/UnboundVariable.txt b/dhall/src/error/text/UnboundVariable.txt
index bd7d483..bd7d483 100644
--- a/dhall/src/errors/UnboundVariable.txt
+++ b/dhall/src/error/text/UnboundVariable.txt
diff --git a/dhall/src/errors/Untyped.txt b/dhall/src/error/text/Untyped.txt
index 4904bf8..4904bf8 100644
--- a/dhall/src/errors/Untyped.txt
+++ b/dhall/src/error/text/Untyped.txt
diff --git a/dhall/src/errors/UnusedHandler.txt b/dhall/src/error/text/UnusedHandler.txt
index 2e46a12..2e46a12 100644
--- a/dhall/src/errors/UnusedHandler.txt
+++ b/dhall/src/error/text/UnusedHandler.txt