From b0def14513c60a8ea44fc03e1b08cbf55caceecf Mon Sep 17 00:00:00 2001
From: Ethan-000 <s2026080@ed.ac.uk>
Date: Mon, 7 Aug 2023 15:13:41 +0100
Subject: [PATCH] chore: Improve unary error (#2199)

* unary error

* .

* Update crates/noirc_frontend/src/hir/type_check/errors.rs

---------

Co-authored-by: jfecher <jake@aztecprotocol.com>
---
 crates/noirc_frontend/src/hir/type_check/errors.rs | 3 +++
 crates/noirc_frontend/src/hir/type_check/expr.rs   | 8 +++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/crates/noirc_frontend/src/hir/type_check/errors.rs b/crates/noirc_frontend/src/hir/type_check/errors.rs
index 4f032503f3d..8b3623db3c3 100644
--- a/crates/noirc_frontend/src/hir/type_check/errors.rs
+++ b/crates/noirc_frontend/src/hir/type_check/errors.rs
@@ -71,6 +71,8 @@ pub enum TypeCheckError {
     IntegerBitWidth { bit_width_x: u32, bit_width_y: u32, span: Span },
     #[error("{kind} cannot be used in an infix operation")]
     InvalidInfixOp { kind: &'static str, span: Span },
+    #[error("{kind} cannot be used in a unary operation")]
+    InvalidUnaryOp { kind: String, span: Span },
     #[error("Bitwise operations are invalid on Field types. Try casting the operands to a sized integer type first.")]
     InvalidBitwiseOperationOnField { span: Span },
     #[error("Integer cannot be used with type {typ}")]
@@ -174,6 +176,7 @@ impl From<TypeCheckError> for Diagnostic {
             | TypeCheckError::IntegerSignedness { span, .. }
             | TypeCheckError::IntegerBitWidth { span, .. }
             | TypeCheckError::InvalidInfixOp { span, .. }
+            | TypeCheckError::InvalidUnaryOp { span, .. }
             | TypeCheckError::InvalidBitwiseOperationOnField { span, .. }
             | TypeCheckError::IntegerTypeMismatch { span, .. }
             | TypeCheckError::FieldComparison { span, .. }
diff --git a/crates/noirc_frontend/src/hir/type_check/expr.rs b/crates/noirc_frontend/src/hir/type_check/expr.rs
index 6c111a1d6a0..5bc6aa45359 100644
--- a/crates/noirc_frontend/src/hir/type_check/expr.rs
+++ b/crates/noirc_frontend/src/hir/type_check/expr.rs
@@ -1088,7 +1088,13 @@ impl<'interner> TypeChecker<'interner> {
         };
 
         match op {
-            crate::UnaryOp::Minus => unify(Type::polymorphic_integer(self.interner)),
+            crate::UnaryOp::Minus => {
+                let expected = Type::polymorphic_integer(self.interner);
+                rhs_type.unify(&expected, span, &mut self.errors, || {
+                    TypeCheckError::InvalidUnaryOp { kind: rhs_type.to_string(), span }
+                });
+                expected
+            }
             crate::UnaryOp::Not => {
                 let rhs_type = rhs_type.follow_bindings();