From 88326ab0afdfeb86be3096ec76392a1ad663421c Mon Sep 17 00:00:00 2001
From: Rua <ruawhitepaw@gmail.com>
Date: Wed, 15 Apr 2026 15:01:47 +0200
Subject: [PATCH 1/2] transpile: Do not require `expr` for
 `convert_cast_to_enum`

---
 c2rust-transpile/src/translator/mod.rs      | 10 +---------
 c2rust-transpile/src/translator/pointers.rs |  3 +--
 2 files changed, 2 insertions(+), 11 deletions(-)

diff --git a/c2rust-transpile/src/translator/mod.rs b/c2rust-transpile/src/translator/mod.rs
index e986c89aeb..343286b34f 100644
--- a/c2rust-transpile/src/translator/mod.rs
+++ b/c2rust-transpile/src/translator/mod.rs
@@ -4228,16 +4228,8 @@ impl<'c> Translation<'c> {
                     self.f128_cast_to(val, target_ty_kind)
                 } else if let &CTypeKind::Enum(enum_decl_id) = target_ty_kind {
                     // Casts targeting `enum` types...
-                    let expr =
-                        expr.ok_or_else(|| format_err!("Casts to enums require a C ExprId"))?;
                     val.result_map(|val| {
-                        self.convert_cast_to_enum(
-                            ctx,
-                            target_cty.ctype,
-                            enum_decl_id,
-                            Some(expr),
-                            val,
-                        )
+                        self.convert_cast_to_enum(ctx, target_cty.ctype, enum_decl_id, expr, val)
                     })
                 } else if target_ty_kind.is_floating_type() && source_ty_kind.is_bool() {
                     Ok(val.map(|val| {
diff --git a/c2rust-transpile/src/translator/pointers.rs b/c2rust-transpile/src/translator/pointers.rs
index cd678edafa..eb58f47a52 100644
--- a/c2rust-transpile/src/translator/pointers.rs
+++ b/c2rust-transpile/src/translator/pointers.rs
@@ -547,9 +547,8 @@ impl<'c> Translation<'c> {
                 )))
             })
         } else if let &CTypeKind::Enum(enum_decl_id) = target_ty_kind {
-            let expr = expr.ok_or_else(|| format_err!("Casts to enums require a C ExprId"))?;
             val.result_map(|val| {
-                self.convert_cast_to_enum(ctx, target_cty, enum_decl_id, Some(expr), val)
+                self.convert_cast_to_enum(ctx, target_cty, enum_decl_id, expr, val)
             })
         } else {
             Ok(val.map(|val| mk().cast_expr(val, target_ty)))

From eeece581dfb7305f7db029a3cbc248226744a1c5 Mon Sep 17 00:00:00 2001
From: Rua <ruawhitepaw@gmail.com>
Date: Wed, 15 Apr 2026 15:02:03 +0200
Subject: [PATCH 2/2] transpile: Include enums in `CastKind::from_types`

---
 c2rust-transpile/src/c_ast/mod.rs | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/c2rust-transpile/src/c_ast/mod.rs b/c2rust-transpile/src/c_ast/mod.rs
index b83171902c..7f06c74aab 100644
--- a/c2rust-transpile/src/c_ast/mod.rs
+++ b/c2rust-transpile/src/c_ast/mod.rs
@@ -1803,17 +1803,17 @@ impl CastKind {
 
             (CTypeKind::Function(..), CTypeKind::Pointer(..)) => CastKind::FunctionToPointerDecay,
 
-            (_, CTypeKind::Pointer(..)) if source_ty_kind.is_integral_type() => {
+            (_, CTypeKind::Pointer(..)) if source_ty_kind.is_enum_or_integral_type() => {
                 CastKind::IntegralToPointer
             }
 
             (CTypeKind::Pointer(..), CTypeKind::Bool) => CastKind::PointerToBoolean,
 
-            (CTypeKind::Pointer(..), _) if target_ty_kind.is_integral_type() => {
+            (CTypeKind::Pointer(..), _) if target_ty_kind.is_enum_or_integral_type() => {
                 CastKind::PointerToIntegral
             }
 
-            (_, CTypeKind::Bool) if source_ty_kind.is_integral_type() => {
+            (_, CTypeKind::Bool) if source_ty_kind.is_enum_or_integral_type() => {
                 CastKind::IntegralToBoolean
             }
 
@@ -1821,11 +1821,17 @@ impl CastKind {
                 CastKind::BooleanToSignedIntegral
             }
 
-            (_, _) if source_ty_kind.is_integral_type() && target_ty_kind.is_integral_type() => {
+            (_, _)
+                if source_ty_kind.is_enum_or_integral_type()
+                    && target_ty_kind.is_enum_or_integral_type() =>
+            {
                 CastKind::IntegralCast
             }
 
-            (_, _) if source_ty_kind.is_integral_type() && target_ty_kind.is_floating_type() => {
+            (_, _)
+                if source_ty_kind.is_enum_or_integral_type()
+                    && target_ty_kind.is_floating_type() =>
+            {
                 CastKind::IntegralToFloating
             }
 
@@ -1833,7 +1839,10 @@ impl CastKind {
                 CastKind::FloatingToBoolean
             }
 
-            (_, _) if source_ty_kind.is_floating_type() && target_ty_kind.is_integral_type() => {
+            (_, _)
+                if source_ty_kind.is_floating_type()
+                    && target_ty_kind.is_enum_or_integral_type() =>
+            {
                 CastKind::FloatingToIntegral
             }
 
@@ -2684,6 +2693,10 @@ impl CTypeKind {
         matches!(*self, Self::Enum { .. })
     }
 
+    pub fn is_enum_or_integral_type(&self) -> bool {
+        self.is_integral_type() || self.is_enum()
+    }
+
     pub fn is_integral_type(&self) -> bool {
         self.is_unsigned_integral_type() || self.is_signed_integral_type()
     }