Show integer literal range limits on IntegerOutOfBounds

noir-lang · Jul 4, 2024 · 70d6c5e · 70d6c5e
1 parent c0feadf
commit 70d6c5e
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Showing 3 changed files with 44 additions and 24 deletions.
diff --git a/compiler/noirc_evaluator/src/errors.rs b/compiler/noirc_evaluator/src/errors.rs
@@ -23,8 +23,13 @@ pub enum RuntimeError {
     IndexOutOfBounds { index: usize, array_size: usize, call_stack: CallStack },
     #[error("Range constraint of {num_bits} bits is too large for the Field size")]
     InvalidRangeConstraint { num_bits: u32, call_stack: CallStack },
-    #[error("{value} does not fit within the type bounds for {typ}")]
-    IntegerOutOfBounds { value: FieldElement, typ: NumericType, call_stack: CallStack },
+    #[error("The value `{value:?}` cannot fit into `{typ}` which has range `{range}`")]
+    IntegerOutOfBounds {
+        value: FieldElement,
+        typ: NumericType,
+        range: String,
+        call_stack: CallStack,
+    },
     #[error("Expected array index to fit into a u64")]
     TypeConversion { from: String, into: String, call_stack: CallStack },
     #[error("{name:?} is not initialized")]

diff --git a/compiler/noirc_evaluator/src/ssa/ir/types.rs b/compiler/noirc_evaluator/src/ssa/ir/types.rs
@@ -29,23 +29,37 @@ impl NumericType {
         }
     }
 
-    /// Returns true if the given Field value is within the numeric limits
-    /// for the current NumericType.
-    pub(crate) fn value_is_within_limits(self, field: FieldElement, negative: bool) -> bool {
+    /// Returns None if the given Field value is within the numeric limits
+    /// for the current NumericType. Otherwise returns a string describing
+    /// the limits, as a range.
+    pub(crate) fn value_is_outside_limits(
+        self,
+        field: FieldElement,
+        negative: bool,
+    ) -> Option<String> {
         match self {
             NumericType::Unsigned { bit_size } => {
+                let max = 2u128.pow(bit_size) - 1;
                 if negative {
-                    return false;
+                    return Some(format!("0..={}", max));
+                }
+                if field <= max.into() {
+                    None
+                } else {
+                    Some(format!("0..={}", max))
                 }
-                let max = 2u128.pow(bit_size) - 1;
-                field <= max.into()
             }
             NumericType::Signed { bit_size } => {
-                let max =
-                    if negative { 2u128.pow(bit_size - 1) } else { 2u128.pow(bit_size - 1) - 1 };
-                field <= max.into()
+                let min = 2u128.pow(bit_size - 1);
+                let max = 2u128.pow(bit_size - 1) - 1;
+                let target_max = if negative { min } else { max };
+                if field <= target_max.into() {
+                    None
+                } else {
+                    Some(format!("-{}..={}", min, max))
+                }
             }
-            NumericType::NativeField => true,
+            NumericType::NativeField => None,
         }
     }
 }
@@ -224,21 +238,21 @@ mod tests {
     use super::*;
 
     #[test]
-    fn test_u8_is_within_limits() {
+    fn test_u8_value_is_outside_limits() {
         let u8 = NumericType::Unsigned { bit_size: 8 };
-        assert!(!u8.value_is_within_limits(FieldElement::from(1_i128), true));
-        assert!(u8.value_is_within_limits(FieldElement::from(0_i128), false));
-        assert!(u8.value_is_within_limits(FieldElement::from(255_i128), false));
-        assert!(!u8.value_is_within_limits(FieldElement::from(256_i128), false));
+        assert!(u8.value_is_outside_limits(FieldElement::from(1_i128), true).is_some());
+        assert!(u8.value_is_outside_limits(FieldElement::from(0_i128), false).is_none());
+        assert!(u8.value_is_outside_limits(FieldElement::from(255_i128), false).is_none());
+        assert!(u8.value_is_outside_limits(FieldElement::from(256_i128), false).is_some());
     }
 
     #[test]
-    fn test_i8_is_within_limits() {
+    fn test_i8_value_is_outside_limits() {
         let i8 = NumericType::Signed { bit_size: 8 };
-        assert!(!i8.value_is_within_limits(FieldElement::from(129_i128), true));
-        assert!(i8.value_is_within_limits(FieldElement::from(128_i128), true));
-        assert!(i8.value_is_within_limits(FieldElement::from(0_i128), false));
-        assert!(i8.value_is_within_limits(FieldElement::from(127_i128), false));
-        assert!(!i8.value_is_within_limits(FieldElement::from(128_i128), false));
+        assert!(i8.value_is_outside_limits(FieldElement::from(129_i128), true).is_some());
+        assert!(i8.value_is_outside_limits(FieldElement::from(128_i128), true).is_none());
+        assert!(i8.value_is_outside_limits(FieldElement::from(0_i128), false).is_none());
+        assert!(i8.value_is_outside_limits(FieldElement::from(127_i128), false).is_none());
+        assert!(i8.value_is_outside_limits(FieldElement::from(128_i128), false).is_some());
     }
 }
diff --git a/compiler/noirc_evaluator/src/ssa/ssa_gen/context.rs b/compiler/noirc_evaluator/src/ssa/ssa_gen/context.rs
@@ -272,11 +272,12 @@ impl<'a> FunctionContext<'a> {
         let value = value.into();
 
         if let Type::Numeric(numeric_type) = typ {
-            if !numeric_type.value_is_within_limits(value, negative) {
+            if let Some(range) = numeric_type.value_is_outside_limits(value, negative) {
                 let call_stack = self.builder.get_call_stack();
                 return Err(RuntimeError::IntegerOutOfBounds {
                     value,
                     typ: numeric_type,
+                    range: range,
                     call_stack,
                 });
             }