chore: make spans non-optional on UnresolvedType (#5773)

---

# Description

## Problem\*

Resolves <!-- Link to GitHub Issue -->

## Summary\*

This PR pulls out the change to make spans on `UnresolvedType` mandatory
to reduce the diff from #5739

## Additional Context



## Documentation\*

Check one:
- [x] No documentation needed.
- [ ] Documentation included in this PR.
- [ ] **[For Experimental Features]** Documentation to be submitted in a
separate PR.

# PR Checklist\*

- [x] I have tested the changes locally.
- [x] I have formatted the changes with [Prettier](https://prettier.io/)
and/or `cargo fmt` on default settings.

---------

Co-authored-by: Jake Fecher <jake@aztecprotocol.com>

Author: TomAFrench

aztec_macros/src/transforms/functions.rs

@@ -267,7 +267,7 @@ fn create_inputs(ty: &str) -> Param {
     let path_snippet = ty.to_case(Case::Snake); // e.g. private_context_inputs
     let type_path = chained_dep!("aztec", "context", "inputs", &path_snippet, ty);
 
-    let context_type = make_type(UnresolvedTypeData::Named(type_path, vec![], true));
+    let context_type = make_type(UnresolvedTypeData::Named(type_path, Default::default(), true));
     let visibility = Visibility::Private;
 
     Param { pattern: context_pattern, typ: context_type, visibility, span: Span::default() }
@@ -396,7 +396,7 @@ fn serialize_to_hasher(
                         Signedness::Unsigned,
                         ast::IntegerBitSize::ThirtyTwo,
                     ),
-                    span: None,
+                    span: Span::default(),
                 },
                 hasher_name,
             ))
@@ -595,7 +595,7 @@ fn abstract_return_values(func: &NoirFunction) -> Result<Option<Vec<Statement>>,
                 serialize_to_hasher(&ident(return_value_name), &current_return_type, hasher_name)
                     .ok_or_else(|| AztecMacroError::UnsupportedFunctionReturnType {
                     typ: current_return_type.clone(),
-                    span: func.return_type().span.unwrap_or_default(),
+                    span: func.return_type().span,
                 })?;
 
             replacement_statements.extend(serialization_statements);

aztec_macros/src/transforms/note_interface.rs

@@ -62,8 +62,9 @@ pub fn generate_note_interface_impl(
                     note_struct.name.0.contents
                 )),
             })?;
-        let note_interface_impl_span: Option<Span> =
-            if empty_spans { None } else { trait_impl.object_type.span };
+        let note_interface_impl_span =
+            if empty_spans { Span::default() } else { trait_impl.object_type.span };
+
         // Look for the note struct implementation, generate a default one if it doesn't exist (in order to append methods to it)
         let existing_impl = module.impls.iter_mut().find(|r#impl| match &r#impl.object_type.typ {
             UnresolvedTypeData::Named(path, _, _) => path.last_ident().eq(&note_struct.name),
@@ -94,7 +95,7 @@ pub fn generate_note_interface_impl(
                     Ok(val.to_string())
                 }
                 _ => Err(AztecMacroError::CouldNotImplementNoteInterface {
-                    span: trait_impl.object_type.span,
+                    span: Some(trait_impl.object_type.span),
                     secondary_message: Some(format!(
                         "NoteInterface must be generic over NOTE_LEN and NOTE_BYTES_LEN: {}",
                         note_type
@@ -231,7 +232,7 @@ fn generate_note_to_be_bytes(
     note_type: &String,
     byte_length: &str,
     serialized_length: &str,
-    impl_span: Option<Span>,
+    impl_span: Span,
     empty_spans: bool,
 ) -> Result<NoirFunction, AztecMacroError> {
     let function_source = format!(
@@ -268,21 +269,21 @@ fn generate_note_to_be_bytes(
         dbg!(errors);
         return Err(AztecMacroError::CouldNotImplementNoteInterface {
             secondary_message: Some("Failed to parse Noir macro code (fn to_be_bytes). This is either a bug in the compiler or the Noir macro code".to_string()),
-            span: impl_span
+            span: Some(impl_span)
         });
     }
 
     let mut function_ast = function_ast.into_sorted();
     let mut noir_fn = function_ast.functions.remove(0);
-    noir_fn.def.span = impl_span.unwrap_or_default();
+    noir_fn.def.span = impl_span;
     noir_fn.def.visibility = ItemVisibility::Public;
     Ok(noir_fn)
 }
 
 fn generate_note_get_header(
     note_type: &String,
     note_header_field_name: &String,
-    impl_span: Option<Span>,
+    impl_span: Span,
     empty_spans: bool,
 ) -> Result<NoirFunction, AztecMacroError> {
     let function_source = format!(
@@ -300,21 +301,21 @@ fn generate_note_get_header(
         dbg!(errors);
         return Err(AztecMacroError::CouldNotImplementNoteInterface {
             secondary_message: Some("Failed to parse Noir macro code (fn get_header). This is either a bug in the compiler or the Noir macro code".to_string()),
-            span: impl_span
+            span: Some(impl_span)
         });
     }
 
     let mut function_ast = function_ast.into_sorted();
     let mut noir_fn = function_ast.functions.remove(0);
-    noir_fn.def.span = impl_span.unwrap_or_default();
+    noir_fn.def.span = impl_span;
     noir_fn.def.visibility = ItemVisibility::Public;
     Ok(noir_fn)
 }
 
 fn generate_note_set_header(
     note_type: &String,
     note_header_field_name: &String,
-    impl_span: Option<Span>,
+    impl_span: Span,
     empty_spans: bool,
 ) -> Result<NoirFunction, AztecMacroError> {
     let function_source = format!(
@@ -331,13 +332,13 @@ fn generate_note_set_header(
         dbg!(errors);
         return Err(AztecMacroError::CouldNotImplementNoteInterface  {
             secondary_message: Some("Failed to parse Noir macro code (fn set_header). This is either a bug in the compiler or the Noir macro code".to_string()),
-            span: impl_span
+            span: Some(impl_span)
         });
     }
 
     let mut function_ast = function_ast.into_sorted();
     let mut noir_fn = function_ast.functions.remove(0);
-    noir_fn.def.span = impl_span.unwrap_or_default();
+    noir_fn.def.span = impl_span;
     noir_fn.def.visibility = ItemVisibility::Public;
     Ok(noir_fn)
 }
@@ -346,7 +347,7 @@ fn generate_note_set_header(
 // of the conversion of the characters in the note's struct name to unsigned integers.
 fn generate_get_note_type_id(
     note_type_id: u32,
-    impl_span: Option<Span>,
+    impl_span: Span,
     empty_spans: bool,
 ) -> Result<NoirFunction, AztecMacroError> {
     // TODO(#7165): replace {} with dep::aztec::protocol_types::abis::note_selector::compute_note_selector(\"{}\") in the function source below
@@ -365,13 +366,13 @@ fn generate_get_note_type_id(
         dbg!(errors);
         return Err(AztecMacroError::CouldNotImplementNoteInterface {
             secondary_message: Some("Failed to parse Noir macro code (fn get_note_type_id). This is either a bug in the compiler or the Noir macro code".to_string()),
-            span: impl_span
+            span: Some(impl_span)
         });
     }
 
     let mut function_ast = function_ast.into_sorted();
     let mut noir_fn = function_ast.functions.remove(0);
-    noir_fn.def.span = impl_span.unwrap_or_default();
+    noir_fn.def.span = impl_span;
     noir_fn.def.visibility = ItemVisibility::Public;
     Ok(noir_fn)
 }
@@ -389,7 +390,7 @@ fn generate_note_properties_struct(
     note_type: &str,
     note_fields: &[(String, String)],
     note_header_field_name: &String,
-    impl_span: Option<Span>,
+    impl_span: Span,
     empty_spans: bool,
 ) -> Result<NoirStruct, AztecMacroError> {
     let struct_source =
@@ -400,7 +401,7 @@ fn generate_note_properties_struct(
         dbg!(errors);
         return Err(AztecMacroError::CouldNotImplementNoteInterface {
             secondary_message: Some(format!("Failed to parse Noir macro code (struct {}Properties). This is either a bug in the compiler or the Noir macro code", note_type)),
-            span: impl_span
+            span: Some(impl_span)
         });
     }
 
@@ -423,7 +424,7 @@ fn generate_note_deserialize_content(
     note_fields: &[(String, String)],
     note_serialize_len: &String,
     note_header_field_name: &String,
-    impl_span: Option<Span>,
+    impl_span: Span,
     empty_spans: bool,
 ) -> Result<NoirFunction, AztecMacroError> {
     let function_source = generate_note_deserialize_content_source(
@@ -438,13 +439,13 @@ fn generate_note_deserialize_content(
         dbg!(errors);
         return Err(AztecMacroError::CouldNotImplementNoteInterface {
             secondary_message: Some("Failed to parse Noir macro code (fn deserialize_content). This is either a bug in the compiler or the Noir macro code".to_string()),
-            span: impl_span
+            span: Some(impl_span)
         });
     }
 
     let mut function_ast = function_ast.into_sorted();
     let mut noir_fn = function_ast.functions.remove(0);
-    noir_fn.def.span = impl_span.unwrap_or_default();
+    noir_fn.def.span = impl_span;
     noir_fn.def.visibility = ItemVisibility::Public;
     Ok(noir_fn)
 }
@@ -461,7 +462,7 @@ fn generate_note_serialize_content(
     note_fields: &[(String, String)],
     note_serialize_len: &String,
     note_header_field_name: &String,
-    impl_span: Option<Span>,
+    impl_span: Span,
     empty_spans: bool,
 ) -> Result<NoirFunction, AztecMacroError> {
     let function_source = generate_note_serialize_content_source(
@@ -476,13 +477,13 @@ fn generate_note_serialize_content(
         dbg!(errors);
         return Err(AztecMacroError::CouldNotImplementNoteInterface {
             secondary_message: Some("Failed to parse Noir macro code (fn serialize_content). This is either a bug in the compiler or the Noir macro code".to_string()),
-            span: impl_span
+            span: Some(impl_span)
         });
     }
 
     let mut function_ast = function_ast.into_sorted();
     let mut noir_fn = function_ast.functions.remove(0);
-    noir_fn.def.span = impl_span.unwrap_or_default();
+    noir_fn.def.span = impl_span;
     noir_fn.def.visibility = ItemVisibility::Public;
     Ok(noir_fn)
 }
@@ -492,7 +493,7 @@ fn generate_note_properties_fn(
     note_type: &str,
     note_fields: &[(String, String)],
     note_header_field_name: &String,
-    impl_span: Option<Span>,
+    impl_span: Span,
     empty_spans: bool,
 ) -> Result<NoirFunction, AztecMacroError> {
     let function_source =
@@ -502,12 +503,12 @@ fn generate_note_properties_fn(
         dbg!(errors);
         return Err(AztecMacroError::CouldNotImplementNoteInterface {
             secondary_message: Some("Failed to parse Noir macro code (fn properties). This is either a bug in the compiler or the Noir macro code".to_string()),
-            span: impl_span
+            span: Some(impl_span)
         });
     }
     let mut function_ast = function_ast.into_sorted();
     let mut noir_fn = function_ast.functions.remove(0);
-    noir_fn.def.span = impl_span.unwrap_or_default();
+    noir_fn.def.span = impl_span;
     noir_fn.def.visibility = ItemVisibility::Public;
     Ok(noir_fn)
 }
@@ -519,7 +520,7 @@ fn generate_note_properties_fn(
 //
 fn generate_compute_note_hiding_point(
     note_type: &String,
-    impl_span: Option<Span>,
+    impl_span: Span,
     empty_spans: bool,
 ) -> Result<NoirFunction, AztecMacroError> {
     // TODO(#7771): update this to do only 1 MSM call
@@ -541,12 +542,12 @@ fn generate_compute_note_hiding_point(
         dbg!(errors);
         return Err(AztecMacroError::CouldNotImplementNoteInterface {
             secondary_message: Some("Failed to parse Noir macro code (fn compute_note_hiding_point). This is either a bug in the compiler or the Noir macro code".to_string()),
-            span: impl_span
+            span: Some(impl_span)
         });
     }
     let mut function_ast = function_ast.into_sorted();
     let mut noir_fn = function_ast.functions.remove(0);
-    noir_fn.def.span = impl_span.unwrap_or_default();
+    noir_fn.def.span = impl_span;
     noir_fn.def.visibility = ItemVisibility::Public;
     Ok(noir_fn)
 }

aztec_macros/src/transforms/storage.rs

@@ -238,7 +238,7 @@ pub fn generate_storage_implementation(
                 vec![generic_context_type.clone()],
                 true,
             ),
-            span: Some(Span::default()),
+            span: Span::default(),
         },
         type_span: Span::default(),
         generics: vec![generic_context_ident.into()],

aztec_macros/src/utils/ast_utils.rs

@@ -108,17 +108,14 @@ pub fn assignment_with_type(
 }
 
 pub fn return_type(path: Path) -> FunctionReturnType {
-    let ty = make_type(UnresolvedTypeData::Named(path, vec![], true));
+    let ty = make_type(UnresolvedTypeData::Named(path, Default::default(), true));
     FunctionReturnType::Ty(ty)
 }
 
 pub fn lambda(parameters: Vec<(Pattern, UnresolvedType)>, body: Expression) -> Expression {
     expression(ExpressionKind::Lambda(Box::new(Lambda {
         parameters,
-        return_type: UnresolvedType {
-            typ: UnresolvedTypeData::Unspecified,
-            span: Some(Span::default()),
-        },
+        return_type: UnresolvedType { typ: UnresolvedTypeData::Unspecified, span: Span::default() },
         body,
     })))
 }
@@ -179,7 +176,7 @@ pub fn cast(lhs: Expression, ty: UnresolvedTypeData) -> Expression {
 }
 
 pub fn make_type(typ: UnresolvedTypeData) -> UnresolvedType {
-    UnresolvedType { typ, span: Some(Span::default()) }
+    UnresolvedType { typ, span: Span::default() }
 }
 
 pub fn index_array(array: Ident, index: &str) -> Expression {

compiler/noirc_frontend/src/ast/expression.rs

@@ -69,9 +69,7 @@ impl UnresolvedGeneric {
     pub fn span(&self) -> Span {
         match self {
             UnresolvedGeneric::Variable(ident) => ident.0.span(),
-            UnresolvedGeneric::Numeric { ident, typ } => {
-                ident.0.span().merge(typ.span.unwrap_or_default())
-            }
+            UnresolvedGeneric::Numeric { ident, typ } => ident.0.span().merge(typ.span),
             UnresolvedGeneric::Resolved(_, span) => *span,
         }
     }
@@ -791,7 +789,7 @@ impl FunctionDefinition {
                 visibility: Visibility::Private,
                 pattern: Pattern::Identifier(ident.clone()),
                 typ: unresolved_type.clone(),
-                span: ident.span().merge(unresolved_type.span.unwrap()),
+                span: ident.span().merge(unresolved_type.span),
             })
             .collect();
 
@@ -848,7 +846,7 @@ impl FunctionReturnType {
     pub fn get_type(&self) -> Cow<UnresolvedType> {
         match self {
             FunctionReturnType::Default(span) => {
-                Cow::Owned(UnresolvedType { typ: UnresolvedTypeData::Unit, span: Some(*span) })
+                Cow::Owned(UnresolvedType { typ: UnresolvedTypeData::Unit, span: *span })
             }
             FunctionReturnType::Ty(typ) => Cow::Borrowed(typ),
         }

compiler/noirc_frontend/src/ast/function.rs

@@ -61,9 +61,7 @@ impl NoirFunction {
 
     pub fn return_type(&self) -> UnresolvedType {
         match &self.def.return_type {
-            FunctionReturnType::Default(_) => {
-                UnresolvedType::without_span(UnresolvedTypeData::Unit)
-            }
+            FunctionReturnType::Default(span) => UnresolvedTypeData::Unit.with_span(*span),
             FunctionReturnType::Ty(ty) => ty.clone(),
         }
     }

compiler/noirc_frontend/src/ast/mod.rs

@@ -148,11 +148,7 @@ pub enum UnresolvedTypeData {
 #[derive(Debug, PartialEq, Eq, Clone, Hash)]
 pub struct UnresolvedType {
     pub typ: UnresolvedTypeData,
-
-    // The span is None in the cases where the User omitted a type:
-    //  fn Foo() {}  --- return type is UnresolvedType::Unit without a span
-    //  let x = 100; --- type is UnresolvedType::Unspecified without a span
-    pub span: Option<Span>,
+    pub span: Span,
 }
 
 /// Type wrapper for a member access
@@ -184,7 +180,7 @@ pub enum UnresolvedTypeExpression {
 
 impl Recoverable for UnresolvedType {
     fn error(span: Span) -> Self {
-        UnresolvedType { typ: UnresolvedTypeData::Error, span: Some(span) }
+        UnresolvedType { typ: UnresolvedTypeData::Error, span }
     }
 }
 
@@ -280,14 +276,6 @@ impl UnresolvedType {
         }
     }
 
-    pub fn without_span(typ: UnresolvedTypeData) -> UnresolvedType {
-        UnresolvedType { typ, span: None }
-    }
-
-    pub fn unspecified() -> UnresolvedType {
-        UnresolvedType { typ: UnresolvedTypeData::Unspecified, span: None }
-    }
-
     pub(crate) fn is_type_expression(&self) -> bool {
         matches!(&self.typ, UnresolvedTypeData::Expression(_))
     }
@@ -309,7 +297,7 @@ impl UnresolvedTypeData {
     }
 
     pub fn with_span(&self, span: Span) -> UnresolvedType {
-        UnresolvedType { typ: self.clone(), span: Some(span) }
+        UnresolvedType { typ: self.clone(), span }
     }
 }