diff --git a/crates/hir-def/src/data.rs b/crates/hir-def/src/data.rs
index 9d368911a4..de1e10ae2b 100644
--- a/crates/hir-def/src/data.rs
+++ b/crates/hir-def/src/data.rs
@@ -30,7 +30,7 @@ use crate::{
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct FunctionData {
     pub name: Name,
-    pub params: Vec<(Option<Name>, Interned<TypeRef>)>,
+    pub params: Vec<Interned<TypeRef>>,
     pub ret_type: Interned<TypeRef>,
     pub attrs: Attrs,
     pub visibility: RawVisibility,
@@ -100,7 +100,7 @@ impl FunctionData {
             params: enabled_params
                 .clone()
                 .filter_map(|id| match &item_tree[id] {
-                    Param::Normal(name, ty) => Some((name.clone(), ty.clone())),
+                    Param::Normal(_, ty) => Some(ty.clone()),
                     Param::Varargs => None,
                 })
                 .collect(),
diff --git a/crates/hir-def/src/generics.rs b/crates/hir-def/src/generics.rs
index 354b8fd0af..4285a0ca72 100644
--- a/crates/hir-def/src/generics.rs
+++ b/crates/hir-def/src/generics.rs
@@ -176,7 +176,7 @@ impl GenericParams {
                 // Don't create an `Expander` nor call `loc.source(db)` if not needed since this
                 // causes a reparse after the `ItemTree` has been created.
                 let mut expander = Lazy::new(|| Expander::new(db, loc.source(db).file_id, module));
-                for (_, param) in &func_data.params {
+                for param in &func_data.params {
                     generic_params.fill_implicit_impl_trait_args(db, &mut expander, param);
                 }
 
diff --git a/crates/hir-ty/src/infer.rs b/crates/hir-ty/src/infer.rs
index 76fd3effc0..c34b24bee8 100644
--- a/crates/hir-ty/src/infer.rs
+++ b/crates/hir-ty/src/infer.rs
@@ -618,7 +618,7 @@ impl<'a> InferenceContext<'a> {
         let ctx = crate::lower::TyLoweringContext::new(self.db, &self.resolver)
             .with_impl_trait_mode(ImplTraitLoweringMode::Param);
         let mut param_tys =
-            data.params.iter().map(|(_, type_ref)| ctx.lower_ty(type_ref)).collect::<Vec<_>>();
+            data.params.iter().map(|type_ref| ctx.lower_ty(type_ref)).collect::<Vec<_>>();
         // Check if function contains a va_list, if it does then we append it to the parameter types
         // that are collected from the function data
         if data.is_varargs() {
diff --git a/crates/hir-ty/src/lower.rs b/crates/hir-ty/src/lower.rs
index c4326f98cd..d69fd8c811 100644
--- a/crates/hir-ty/src/lower.rs
+++ b/crates/hir-ty/src/lower.rs
@@ -1634,7 +1634,7 @@ fn fn_sig_for_fn(db: &dyn HirDatabase, def: FunctionId) -> PolyFnSig {
     let ctx_params = TyLoweringContext::new(db, &resolver)
         .with_impl_trait_mode(ImplTraitLoweringMode::Variable)
         .with_type_param_mode(ParamLoweringMode::Variable);
-    let params = data.params.iter().map(|(_, tr)| ctx_params.lower_ty(tr)).collect::<Vec<_>>();
+    let params = data.params.iter().map(|tr| ctx_params.lower_ty(tr)).collect::<Vec<_>>();
     let ctx_ret = TyLoweringContext::new(db, &resolver)
         .with_impl_trait_mode(ImplTraitLoweringMode::Opaque)
         .with_type_param_mode(ParamLoweringMode::Variable);
diff --git a/crates/hir/src/display.rs b/crates/hir/src/display.rs
index 7cb29114d7..49165ca70e 100644
--- a/crates/hir/src/display.rs
+++ b/crates/hir/src/display.rs
@@ -8,6 +8,7 @@ use hir_def::{
     type_ref::{TypeBound, TypeRef},
     AdtId, GenericDefId,
 };
+use hir_expand::name;
 use hir_ty::{
     display::{
         write_bounds_like_dyn_trait_with_prefix, write_visibility, HirDisplay, HirDisplayError,
@@ -76,22 +77,22 @@ impl HirDisplay for Function {
         };
 
         let mut first = true;
-        for (name, type_ref) in &data.params {
+        // FIXME: Use resolved `param.ty` once we no longer discard lifetimes
+        for (type_ref, param) in data.params.iter().zip(self.assoc_fn_params(db)) {
+            let local = param.as_local(db).map(|it| it.name(db));
             if !first {
                 f.write_str(", ")?;
             } else {
                 first = false;
-                if data.has_self_param() {
+                if local == Some(name!(self)) {
                     write_self_param(type_ref, f)?;
                     continue;
                 }
             }
-            match name {
+            match local {
                 Some(name) => write!(f, "{name}: ")?,
                 None => f.write_str("_: ")?,
             }
-            // FIXME: Use resolved `param.ty` or raw `type_ref`?
-            // The former will ignore lifetime arguments currently.
             type_ref.hir_fmt(f)?;
         }
 
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index a355ea1642..fad9f19d25 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -1844,7 +1844,7 @@ impl Param {
     }
 
     pub fn name(&self, db: &dyn HirDatabase) -> Option<Name> {
-        db.function_data(self.func.id).params[self.idx].0.clone()
+        Some(self.as_local(db)?.name(db))
     }
 
     pub fn as_local(&self, db: &dyn HirDatabase) -> Option<Local> {
@@ -1885,7 +1885,7 @@ impl SelfParam {
         func_data
             .params
             .first()
-            .map(|(_, param)| match &**param {
+            .map(|param| match &**param {
                 TypeRef::Reference(.., mutability) => match mutability {
                     hir_def::type_ref::Mutability::Shared => Access::Shared,
                     hir_def::type_ref::Mutability::Mut => Access::Exclusive,