From 4b488a54874137fe01cd7dd211277aa69b6d030d Mon Sep 17 00:00:00 2001
From: Soares Chen <soares.chen@maybevoid.com>
Date: Fri, 27 Feb 2026 21:48:51 +0100
Subject: [PATCH 1/5] Fix UseType with self referential bound

---
 .../src/derive_component/derive.rs            |  4 +-
 .../cgp-macro-lib/src/entrypoints/cgp_type.rs | 13 ++++-
 .../src/type_component/derive.rs              | 12 ++--
 .../cgp-macro-lib/src/type_component/mod.rs   |  1 +
 .../src/type_component/replace.rs             | 39 +++++++++++++
 .../cgp-tests/tests/cgp_fn_tests/use_type.rs  | 57 ++++++++++++++++---
 6 files changed, 108 insertions(+), 18 deletions(-)
 create mode 100644 crates/cgp-macro-lib/src/type_component/replace.rs

diff --git a/crates/cgp-macro-lib/src/derive_component/derive.rs b/crates/cgp-macro-lib/src/derive_component/derive.rs
index bd4a4c07..32de632b 100644
--- a/crates/cgp-macro-lib/src/derive_component/derive.rs
+++ b/crates/cgp-macro-lib/src/derive_component/derive.rs
@@ -54,8 +54,8 @@ pub fn derive_component_with_ast(
     )?;
 
     let mut item_impls = vec![
+        provider_impl.clone(),
         consumer_impl,
-        provider_impl,
         use_context_impl,
         use_context_is_provider_impl,
     ];
@@ -80,6 +80,7 @@ pub fn derive_component_with_ast(
         component_struct,
         consumer_trait,
         provider_trait,
+        provider_impl,
         item_impls,
     };
 
@@ -90,6 +91,7 @@ pub struct DerivedComponent {
     pub component_struct: ItemStruct,
     pub consumer_trait: ItemTrait,
     pub provider_trait: ItemTrait,
+    pub provider_impl: ItemImpl,
     pub item_impls: Vec<ItemImpl>,
 }
 
diff --git a/crates/cgp-macro-lib/src/entrypoints/cgp_type.rs b/crates/cgp-macro-lib/src/entrypoints/cgp_type.rs
index 4aac783a..27a047ba 100644
--- a/crates/cgp-macro-lib/src/entrypoints/cgp_type.rs
+++ b/crates/cgp-macro-lib/src/entrypoints/cgp_type.rs
@@ -7,7 +7,9 @@ use syn::{Ident, ItemTrait, parse_quote, parse2};
 
 use crate::derive_component::derive_component_with_ast;
 use crate::parse::{ComponentSpec, Entries};
-use crate::type_component::{derive_type_alias, derive_type_providers, extract_item_type};
+use crate::type_component::{
+    derive_type_alias, derive_type_providers, extract_item_type_from_trait,
+};
 
 pub fn cgp_type(attrs: TokenStream, body: TokenStream) -> syn::Result<TokenStream> {
     let mut entries = if let Ok(provider_ident) = parse2::<Ident>(attrs.clone()) {
@@ -18,7 +20,7 @@ pub fn cgp_type(attrs: TokenStream, body: TokenStream) -> syn::Result<TokenStrea
 
     let consumer_trait: ItemTrait = syn::parse2(body)?;
 
-    let item_type = extract_item_type(&consumer_trait)?.clone();
+    let item_type = extract_item_type_from_trait(&consumer_trait)?.clone();
 
     entries.entry("provider".into()).or_insert_with(|| {
         let provider_name = Ident::new(
@@ -34,7 +36,12 @@ pub fn cgp_type(attrs: TokenStream, body: TokenStream) -> syn::Result<TokenStrea
 
     let alias_type = derive_type_alias(&component.consumer_trait, &spec.context_type, &item_type)?;
 
-    let type_provider_impls = derive_type_providers(&spec, &component.provider_trait, &item_type)?;
+    let type_provider_impls = derive_type_providers(
+        &spec,
+        &component.provider_trait,
+        &component.provider_impl,
+        &item_type,
+    )?;
 
     let mut out = quote! {
         #component
diff --git a/crates/cgp-macro-lib/src/type_component/derive.rs b/crates/cgp-macro-lib/src/type_component/derive.rs
index 1850d21e..eab2e06c 100644
--- a/crates/cgp-macro-lib/src/type_component/derive.rs
+++ b/crates/cgp-macro-lib/src/type_component/derive.rs
@@ -9,8 +9,9 @@ use syn::{
 
 use crate::derive_provider::derive_is_provider_for;
 use crate::parse::ComponentSpec;
+use crate::type_component::replace::get_bounds_and_replace_self_assoc_type;
 
-pub fn extract_item_type(consumer_trait: &ItemTrait) -> syn::Result<&TraitItemType> {
+pub fn extract_item_type_from_trait(consumer_trait: &ItemTrait) -> syn::Result<&TraitItemType> {
     if consumer_trait.items.len() != 1 {
         return Err(Error::new(
             consumer_trait.span(),
@@ -63,15 +64,16 @@ pub fn derive_type_alias(
 pub fn derive_type_providers(
     spec: &ComponentSpec,
     provider_trait: &ItemTrait,
+    provider_impl: &ItemImpl,
     item_type: &TraitItemType,
 ) -> syn::Result<Vec<ItemImpl>> {
     let context_name = &spec.context_type;
 
-    let component_name = {
+    let component_name: Type = {
         let name = &spec.component_name;
         let params = &spec.component_params;
-        parse2::<Type>(quote! { #name < #params > })
-    }?;
+        parse2(quote! { #name < #params > })?
+    };
 
     let provider_trait_name = &provider_trait.ident;
 
@@ -85,7 +87,7 @@ pub fn derive_type_providers(
 
     let type_name = &item_type.ident;
 
-    let type_bounds = &item_type.bounds;
+    let type_bounds = get_bounds_and_replace_self_assoc_type(&item_type);
 
     let use_type_impl: ItemImpl = parse2(quote! {
         impl< #type_name, #impl_generics_params >
diff --git a/crates/cgp-macro-lib/src/type_component/mod.rs b/crates/cgp-macro-lib/src/type_component/mod.rs
index 61eca8a7..42dc01bc 100644
--- a/crates/cgp-macro-lib/src/type_component/mod.rs
+++ b/crates/cgp-macro-lib/src/type_component/mod.rs
@@ -1,3 +1,4 @@
 mod derive;
+mod replace;
 
 pub use derive::*;
diff --git a/crates/cgp-macro-lib/src/type_component/replace.rs b/crates/cgp-macro-lib/src/type_component/replace.rs
new file mode 100644
index 00000000..a97fcb01
--- /dev/null
+++ b/crates/cgp-macro-lib/src/type_component/replace.rs
@@ -0,0 +1,39 @@
+// pub fn replace_self_assoc_type
+
+use syn::punctuated::Punctuated;
+use syn::token::Plus;
+use syn::visit_mut::{VisitMut, visit_type_mut, visit_type_param_bound_mut};
+use syn::{Ident, TraitItemType, Type, TypeParamBound, parse_quote};
+
+pub fn get_bounds_and_replace_self_assoc_type(
+    item_type: &TraitItemType,
+) -> Punctuated<TypeParamBound, Plus> {
+    let mut bounds = item_type.bounds.clone();
+    let mut visitor = ReplaceSelfAssocTypeVisitor {
+        type_ident: item_type.ident.clone(),
+    };
+
+    for bound in &mut bounds {
+        visit_type_param_bound_mut(&mut visitor, bound);
+    }
+
+    bounds
+}
+
+pub struct ReplaceSelfAssocTypeVisitor {
+    pub type_ident: Ident,
+}
+
+impl VisitMut for ReplaceSelfAssocTypeVisitor {
+    fn visit_type_mut(&mut self, node: &mut Type) {
+        if let Type::Path(type_path) = node {
+            let type_ident = &self.type_ident;
+            if type_path == &parse_quote! { Self :: #type_ident } {
+                *node = parse_quote!(#type_ident);
+                return;
+            }
+        }
+
+        visit_type_mut(self, node);
+    }
+}
diff --git a/crates/cgp-tests/tests/cgp_fn_tests/use_type.rs b/crates/cgp-tests/tests/cgp_fn_tests/use_type.rs
index 662a8039..06d1531f 100644
--- a/crates/cgp-tests/tests/cgp_fn_tests/use_type.rs
+++ b/crates/cgp-tests/tests/cgp_fn_tests/use_type.rs
@@ -1,18 +1,57 @@
+use core::f64;
 use std::ops::Mul;
 
 use cgp::prelude::*;
 
-#[cgp_type]
+// #[cgp_type]
+#[cgp_component(ScalarTypeProvider)]
 pub trait HasScalarType {
-    type Scalar;
+    type Scalar: Mul<Output = Self::Scalar> + Clone;
 }
 
 #[cgp_fn]
-#[use_type(HasScalarType::Scalar)]
-pub fn rectangle_area(&self, #[implicit] width: Scalar, #[implicit] height: Scalar) -> Scalar
-where
-    Scalar: Mul<Output = Scalar> + Clone,
-{
-    let res: Scalar = width * height;
-    res
+#[extend(HasScalarType)]
+pub fn rectangle_area(
+    &self,
+    #[implicit] width: Self::Scalar,
+    #[implicit] height: Self::Scalar,
+) -> Self::Scalar {
+    width * height
+}
+
+#[derive(HasField)]
+pub struct F32Rectangle {
+    pub width: f32,
+    pub height: f32,
+}
+
+impl HasScalarType for F32Rectangle {
+    type Scalar = f32;
+}
+
+#[derive(HasField)]
+pub struct F64Rectangle {
+    pub width: f64,
+    pub height: f64,
+}
+
+impl HasScalarType for F64Rectangle {
+    type Scalar = f64;
+}
+
+#[test]
+fn test_rectangle_area() {
+    let f32_rectangle = F32Rectangle {
+        width: 3.0,
+        height: 4.0,
+    };
+
+    assert_eq!(f32_rectangle.rectangle_area(), 12.0);
+
+    let f64_rectangle = F64Rectangle {
+        width: 3.0,
+        height: 4.0,
+    };
+
+    assert_eq!(f64_rectangle.rectangle_area(), 12.0);
 }

From 59b8d82268ee8642f4fbd12460cd498b338c3601 Mon Sep 17 00:00:00 2001
From: Soares Chen <soares.chen@maybevoid.com>
Date: Fri, 27 Feb 2026 21:50:56 +0100
Subject: [PATCH 2/5] Fix WithProvider derivation

---
 crates/cgp-macro-lib/src/derive_component/derive.rs | 4 +---
 crates/cgp-macro-lib/src/entrypoints/cgp_type.rs    | 7 +------
 crates/cgp-macro-lib/src/type_component/derive.rs   | 9 ++++-----
 crates/cgp-tests/tests/cgp_fn_tests/use_type.rs     | 3 +--
 4 files changed, 7 insertions(+), 16 deletions(-)

diff --git a/crates/cgp-macro-lib/src/derive_component/derive.rs b/crates/cgp-macro-lib/src/derive_component/derive.rs
index 32de632b..be02ae26 100644
--- a/crates/cgp-macro-lib/src/derive_component/derive.rs
+++ b/crates/cgp-macro-lib/src/derive_component/derive.rs
@@ -54,7 +54,7 @@ pub fn derive_component_with_ast(
     )?;
 
     let mut item_impls = vec![
-        provider_impl.clone(),
+        provider_impl,
         consumer_impl,
         use_context_impl,
         use_context_is_provider_impl,
@@ -80,7 +80,6 @@ pub fn derive_component_with_ast(
         component_struct,
         consumer_trait,
         provider_trait,
-        provider_impl,
         item_impls,
     };
 
@@ -91,7 +90,6 @@ pub struct DerivedComponent {
     pub component_struct: ItemStruct,
     pub consumer_trait: ItemTrait,
     pub provider_trait: ItemTrait,
-    pub provider_impl: ItemImpl,
     pub item_impls: Vec<ItemImpl>,
 }
 
diff --git a/crates/cgp-macro-lib/src/entrypoints/cgp_type.rs b/crates/cgp-macro-lib/src/entrypoints/cgp_type.rs
index 27a047ba..8fbec5c0 100644
--- a/crates/cgp-macro-lib/src/entrypoints/cgp_type.rs
+++ b/crates/cgp-macro-lib/src/entrypoints/cgp_type.rs
@@ -36,12 +36,7 @@ pub fn cgp_type(attrs: TokenStream, body: TokenStream) -> syn::Result<TokenStrea
 
     let alias_type = derive_type_alias(&component.consumer_trait, &spec.context_type, &item_type)?;
 
-    let type_provider_impls = derive_type_providers(
-        &spec,
-        &component.provider_trait,
-        &component.provider_impl,
-        &item_type,
-    )?;
+    let type_provider_impls = derive_type_providers(&spec, &component.provider_trait, &item_type)?;
 
     let mut out = quote! {
         #component
diff --git a/crates/cgp-macro-lib/src/type_component/derive.rs b/crates/cgp-macro-lib/src/type_component/derive.rs
index eab2e06c..58fd5fdf 100644
--- a/crates/cgp-macro-lib/src/type_component/derive.rs
+++ b/crates/cgp-macro-lib/src/type_component/derive.rs
@@ -64,7 +64,6 @@ pub fn derive_type_alias(
 pub fn derive_type_providers(
     spec: &ComponentSpec,
     provider_trait: &ItemTrait,
-    provider_impl: &ItemImpl,
     item_type: &TraitItemType,
 ) -> syn::Result<Vec<ItemImpl>> {
     let context_name = &spec.context_type;
@@ -104,15 +103,15 @@ pub fn derive_type_providers(
     let use_type_is_provider_impl = derive_is_provider_for(&component_name, &use_type_impl)?;
 
     let with_provider_impl: ItemImpl = parse2(quote! {
-        impl< __Provider__, #impl_generics_params >
+        impl< __Provider__, #type_name, #impl_generics_params >
             #provider_trait_name #type_generics
             for WithProvider< __Provider__ >
         where
-            __Provider__: ProvideType< #context_name, #component_name >,
-            __Provider__::Type: #type_bounds,
+            __Provider__: ProvideType< #context_name, #component_name, Type = #type_name >,
+            #type_name: #type_bounds,
             #predicates
         {
-            type #type_name = __Provider__::Type;
+            type #type_name = #type_name;
         }
     })?;
 
diff --git a/crates/cgp-tests/tests/cgp_fn_tests/use_type.rs b/crates/cgp-tests/tests/cgp_fn_tests/use_type.rs
index 06d1531f..8f43135c 100644
--- a/crates/cgp-tests/tests/cgp_fn_tests/use_type.rs
+++ b/crates/cgp-tests/tests/cgp_fn_tests/use_type.rs
@@ -3,8 +3,7 @@ use std::ops::Mul;
 
 use cgp::prelude::*;
 
-// #[cgp_type]
-#[cgp_component(ScalarTypeProvider)]
+#[cgp_type]
 pub trait HasScalarType {
     type Scalar: Mul<Output = Self::Scalar> + Clone;
 }

From 8396bfe95049b01adc6fc781a38ca65e0c845811 Mon Sep 17 00:00:00 2001
From: Soares Chen <soares.chen@maybevoid.com>
Date: Fri, 27 Feb 2026 21:53:12 +0100
Subject: [PATCH 3/5] Add test

---
 .../component_tests/abstract_types/mod.rs     |  1 +
 .../abstract_types/self_referential.rs        | 23 +++++++++++++++++++
 2 files changed, 24 insertions(+)
 create mode 100644 crates/cgp-tests/tests/component_tests/abstract_types/self_referential.rs

diff --git a/crates/cgp-tests/tests/component_tests/abstract_types/mod.rs b/crates/cgp-tests/tests/component_tests/abstract_types/mod.rs
index e206b362..ba04dea3 100644
--- a/crates/cgp-tests/tests/component_tests/abstract_types/mod.rs
+++ b/crates/cgp-tests/tests/component_tests/abstract_types/mod.rs
@@ -1,3 +1,4 @@
 pub mod basic;
 pub mod extend;
 pub mod foreign;
+pub mod self_referential;
diff --git a/crates/cgp-tests/tests/component_tests/abstract_types/self_referential.rs b/crates/cgp-tests/tests/component_tests/abstract_types/self_referential.rs
new file mode 100644
index 00000000..ee7112b4
--- /dev/null
+++ b/crates/cgp-tests/tests/component_tests/abstract_types/self_referential.rs
@@ -0,0 +1,23 @@
+use core::ops::Mul;
+
+use cgp::prelude::*;
+
+#[cgp_type]
+pub trait HasScalarType {
+    type Scalar: Mul<Output = Self::Scalar> + Clone;
+}
+
+pub struct App;
+
+delegate_components! {
+    App {
+        ScalarTypeProviderComponent:
+            UseType<f64>,
+    }
+}
+
+check_components! {
+    CanUseApp for App {
+        ScalarTypeProviderComponent,
+    }
+}

From 9707786f301fc0fae6b7224a0561f53718ef9b49 Mon Sep 17 00:00:00 2001
From: Soares Chen <soares.chen@maybevoid.com>
Date: Fri, 27 Feb 2026 22:04:21 +0100
Subject: [PATCH 4/5] Fix #[cgp_getter]

---
 .../src/derive_getter/blanket.rs              |  3 +-
 .../src/derive_getter/use_field.rs            |  3 +-
 .../src/derive_getter/use_fields.rs           |  3 +-
 .../src/derive_getter/with_provider.rs        |  3 +-
 .../cgp-macro-lib/src/type_component/mod.rs   |  1 +
 .../tests/getter_tests/assoc_type/mod.rs      |  2 ++
 .../assoc_type/self_referential.rs            | 29 +++++++++++++++++++
 .../assoc_type/self_referential_auto.rs       | 22 ++++++++++++++
 8 files changed, 62 insertions(+), 4 deletions(-)
 create mode 100644 crates/cgp-tests/tests/getter_tests/assoc_type/self_referential.rs
 create mode 100644 crates/cgp-tests/tests/getter_tests/assoc_type/self_referential_auto.rs

diff --git a/crates/cgp-macro-lib/src/derive_getter/blanket.rs b/crates/cgp-macro-lib/src/derive_getter/blanket.rs
index e067a095..24157f5c 100644
--- a/crates/cgp-macro-lib/src/derive_getter/blanket.rs
+++ b/crates/cgp-macro-lib/src/derive_getter/blanket.rs
@@ -9,6 +9,7 @@ use crate::derive_getter::{
     ContextArg, ReceiverMode, derive_getter_constraint, derive_getter_method,
 };
 use crate::symbol::symbol_from_string;
+use crate::type_component::get_bounds_and_replace_self_assoc_type;
 
 pub fn derive_blanket_impl(
     context_type: &Ident,
@@ -39,7 +40,7 @@ pub fn derive_blanket_impl(
             type #field_assoc_type_ident = #field_assoc_type_ident;
         });
 
-        let field_constraints = &field_assoc_type.bounds;
+        let field_constraints = get_bounds_and_replace_self_assoc_type(&field_assoc_type);
 
         generics.make_where_clause().predicates.push(parse2(quote! {
             #field_assoc_type_ident: #field_constraints
diff --git a/crates/cgp-macro-lib/src/derive_getter/use_field.rs b/crates/cgp-macro-lib/src/derive_getter/use_field.rs
index 661e98f4..d6f4e5d6 100644
--- a/crates/cgp-macro-lib/src/derive_getter/use_field.rs
+++ b/crates/cgp-macro-lib/src/derive_getter/use_field.rs
@@ -9,6 +9,7 @@ use crate::derive_getter::{
     ContextArg, ReceiverMode, derive_getter_constraint, derive_getter_method,
 };
 use crate::parse::ComponentSpec;
+use crate::type_component::get_bounds_and_replace_self_assoc_type;
 
 pub fn derive_use_field_impl(
     spec: &ComponentSpec,
@@ -43,7 +44,7 @@ pub fn derive_use_field_impl(
             type #field_assoc_type_ident = #field_assoc_type_ident;
         });
 
-        let field_constraints = &field_assoc_type.bounds;
+        let field_constraints = get_bounds_and_replace_self_assoc_type(&field_assoc_type);
 
         provider_generics
             .make_where_clause()
diff --git a/crates/cgp-macro-lib/src/derive_getter/use_fields.rs b/crates/cgp-macro-lib/src/derive_getter/use_fields.rs
index 9ebdb81e..7605c507 100644
--- a/crates/cgp-macro-lib/src/derive_getter/use_fields.rs
+++ b/crates/cgp-macro-lib/src/derive_getter/use_fields.rs
@@ -10,6 +10,7 @@ use crate::derive_getter::{
 };
 use crate::parse::ComponentSpec;
 use crate::symbol::symbol_from_string;
+use crate::type_component::get_bounds_and_replace_self_assoc_type;
 
 pub fn derive_use_fields_impl(
     spec: &ComponentSpec,
@@ -36,7 +37,7 @@ pub fn derive_use_fields_impl(
             type #field_assoc_type_ident = #field_assoc_type_ident;
         });
 
-        let field_constraints = &field_assoc_type.bounds;
+        let field_constraints = get_bounds_and_replace_self_assoc_type(&field_assoc_type);
 
         provider_generics
             .make_where_clause()
diff --git a/crates/cgp-macro-lib/src/derive_getter/with_provider.rs b/crates/cgp-macro-lib/src/derive_getter/with_provider.rs
index 30a1d0d5..2eaf72cf 100644
--- a/crates/cgp-macro-lib/src/derive_getter/with_provider.rs
+++ b/crates/cgp-macro-lib/src/derive_getter/with_provider.rs
@@ -5,6 +5,7 @@ use syn::{Generics, Ident, ItemImpl, ItemTrait, TraitItemType, parse_quote, pars
 use crate::derive_getter::getter_field::GetterField;
 use crate::derive_getter::{ContextArg, FieldMode, ReceiverMode, derive_getter_method};
 use crate::parse::ComponentSpec;
+use crate::type_component::get_bounds_and_replace_self_assoc_type;
 
 pub fn derive_with_provider_impl(
     spec: &ComponentSpec,
@@ -50,7 +51,7 @@ pub fn derive_with_provider_impl(
             type #field_assoc_type_ident = #field_assoc_type_ident;
         });
 
-        let field_constraints = &field_assoc_type.bounds;
+        let field_constraints = get_bounds_and_replace_self_assoc_type(&field_assoc_type);
 
         provider_generics
             .make_where_clause()
diff --git a/crates/cgp-macro-lib/src/type_component/mod.rs b/crates/cgp-macro-lib/src/type_component/mod.rs
index 42dc01bc..8eaf91af 100644
--- a/crates/cgp-macro-lib/src/type_component/mod.rs
+++ b/crates/cgp-macro-lib/src/type_component/mod.rs
@@ -2,3 +2,4 @@ mod derive;
 mod replace;
 
 pub use derive::*;
+pub use replace::*;
diff --git a/crates/cgp-tests/tests/getter_tests/assoc_type/mod.rs b/crates/cgp-tests/tests/getter_tests/assoc_type/mod.rs
index 98e2c237..5661cac9 100644
--- a/crates/cgp-tests/tests/getter_tests/assoc_type/mod.rs
+++ b/crates/cgp-tests/tests/getter_tests/assoc_type/mod.rs
@@ -1,2 +1,4 @@
 pub mod auto_getter;
 pub mod getter;
+pub mod self_referential;
+pub mod self_referential_auto;
diff --git a/crates/cgp-tests/tests/getter_tests/assoc_type/self_referential.rs b/crates/cgp-tests/tests/getter_tests/assoc_type/self_referential.rs
new file mode 100644
index 00000000..e3aa8502
--- /dev/null
+++ b/crates/cgp-tests/tests/getter_tests/assoc_type/self_referential.rs
@@ -0,0 +1,29 @@
+use core::ops::Mul;
+
+use cgp::prelude::*;
+
+#[cgp_getter]
+pub trait HasScalar {
+    type Scalar: Mul<Output = Self::Scalar> + Clone;
+
+    fn scalar(&self) -> &Self::Scalar;
+}
+
+#[derive(HasField)]
+pub struct App {
+    pub scalar: f64,
+}
+
+delegate_components! {
+    App {
+        ScalarGetterComponent:
+            UseField<Symbol!("scalar")>,
+    }
+}
+
+#[test]
+fn test_auto_getter_scalar() {
+    let app = App { scalar: 2.0 };
+
+    assert_eq!(*app.scalar(), 2.0);
+}
diff --git a/crates/cgp-tests/tests/getter_tests/assoc_type/self_referential_auto.rs b/crates/cgp-tests/tests/getter_tests/assoc_type/self_referential_auto.rs
new file mode 100644
index 00000000..b054d784
--- /dev/null
+++ b/crates/cgp-tests/tests/getter_tests/assoc_type/self_referential_auto.rs
@@ -0,0 +1,22 @@
+use core::ops::Mul;
+
+use cgp::prelude::*;
+
+#[cgp_auto_getter]
+pub trait HasScalarType {
+    type Scalar: Mul<Output = Self::Scalar> + Clone;
+
+    fn scalar(&self) -> &Self::Scalar;
+}
+
+#[derive(HasField)]
+pub struct App {
+    pub scalar: f64,
+}
+
+#[test]
+fn test_auto_getter_scalar() {
+    let app = App { scalar: 2.0 };
+
+    assert_eq!(*app.scalar(), 2.0);
+}

From 59f330a3ed4166ff7aa48d7f92bfd3e063ecd353 Mon Sep 17 00:00:00 2001
From: Soares Chen <soares.chen@maybevoid.com>
Date: Fri, 27 Feb 2026 22:14:48 +0100
Subject: [PATCH 5/5] Fix clippy

---
 crates/cgp-macro-lib/src/derive_getter/blanket.rs       | 2 +-
 crates/cgp-macro-lib/src/derive_getter/use_field.rs     | 2 +-
 crates/cgp-macro-lib/src/derive_getter/use_fields.rs    | 2 +-
 crates/cgp-macro-lib/src/derive_getter/with_provider.rs | 2 +-
 crates/cgp-macro-lib/src/type_component/derive.rs       | 2 +-
 5 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/crates/cgp-macro-lib/src/derive_getter/blanket.rs b/crates/cgp-macro-lib/src/derive_getter/blanket.rs
index 24157f5c..8dc02a9a 100644
--- a/crates/cgp-macro-lib/src/derive_getter/blanket.rs
+++ b/crates/cgp-macro-lib/src/derive_getter/blanket.rs
@@ -40,7 +40,7 @@ pub fn derive_blanket_impl(
             type #field_assoc_type_ident = #field_assoc_type_ident;
         });
 
-        let field_constraints = get_bounds_and_replace_self_assoc_type(&field_assoc_type);
+        let field_constraints = get_bounds_and_replace_self_assoc_type(field_assoc_type);
 
         generics.make_where_clause().predicates.push(parse2(quote! {
             #field_assoc_type_ident: #field_constraints
diff --git a/crates/cgp-macro-lib/src/derive_getter/use_field.rs b/crates/cgp-macro-lib/src/derive_getter/use_field.rs
index d6f4e5d6..cddc1977 100644
--- a/crates/cgp-macro-lib/src/derive_getter/use_field.rs
+++ b/crates/cgp-macro-lib/src/derive_getter/use_field.rs
@@ -44,7 +44,7 @@ pub fn derive_use_field_impl(
             type #field_assoc_type_ident = #field_assoc_type_ident;
         });
 
-        let field_constraints = get_bounds_and_replace_self_assoc_type(&field_assoc_type);
+        let field_constraints = get_bounds_and_replace_self_assoc_type(field_assoc_type);
 
         provider_generics
             .make_where_clause()
diff --git a/crates/cgp-macro-lib/src/derive_getter/use_fields.rs b/crates/cgp-macro-lib/src/derive_getter/use_fields.rs
index 7605c507..068122db 100644
--- a/crates/cgp-macro-lib/src/derive_getter/use_fields.rs
+++ b/crates/cgp-macro-lib/src/derive_getter/use_fields.rs
@@ -37,7 +37,7 @@ pub fn derive_use_fields_impl(
             type #field_assoc_type_ident = #field_assoc_type_ident;
         });
 
-        let field_constraints = get_bounds_and_replace_self_assoc_type(&field_assoc_type);
+        let field_constraints = get_bounds_and_replace_self_assoc_type(field_assoc_type);
 
         provider_generics
             .make_where_clause()
diff --git a/crates/cgp-macro-lib/src/derive_getter/with_provider.rs b/crates/cgp-macro-lib/src/derive_getter/with_provider.rs
index 2eaf72cf..6f470d6a 100644
--- a/crates/cgp-macro-lib/src/derive_getter/with_provider.rs
+++ b/crates/cgp-macro-lib/src/derive_getter/with_provider.rs
@@ -51,7 +51,7 @@ pub fn derive_with_provider_impl(
             type #field_assoc_type_ident = #field_assoc_type_ident;
         });
 
-        let field_constraints = get_bounds_and_replace_self_assoc_type(&field_assoc_type);
+        let field_constraints = get_bounds_and_replace_self_assoc_type(field_assoc_type);
 
         provider_generics
             .make_where_clause()
diff --git a/crates/cgp-macro-lib/src/type_component/derive.rs b/crates/cgp-macro-lib/src/type_component/derive.rs
index 58fd5fdf..d7178613 100644
--- a/crates/cgp-macro-lib/src/type_component/derive.rs
+++ b/crates/cgp-macro-lib/src/type_component/derive.rs
@@ -86,7 +86,7 @@ pub fn derive_type_providers(
 
     let type_name = &item_type.ident;
 
-    let type_bounds = get_bounds_and_replace_self_assoc_type(&item_type);
+    let type_bounds = get_bounds_and_replace_self_assoc_type(item_type);
 
     let use_type_impl: ItemImpl = parse2(quote! {
         impl< #type_name, #impl_generics_params >