diff --git a/c2rust-transpile/src/c_ast/conversion.rs b/c2rust-transpile/src/c_ast/conversion.rs
index 54edf960c9..0fbd335904 100644
--- a/c2rust-transpile/src/c_ast/conversion.rs
+++ b/c2rust-transpile/src/c_ast/conversion.rs
@@ -2294,12 +2294,12 @@ impl ConversionContext {
                         })
                         .collect();
 
-                    let integral_type = node.type_id.map(|x| self.visit_qualified_type(x));
+                    let underlying_type_id = node.type_id.map(|x| self.visit_qualified_type(x));
 
                     let enum_decl = CDeclKind::Enum {
                         name,
                         variants,
-                        integral_type,
+                        underlying_type_id,
                     };
 
                     self.add_decl(new_id, located(node, enum_decl));
diff --git a/c2rust-transpile/src/c_ast/iterators.rs b/c2rust-transpile/src/c_ast/iterators.rs
index a7c1522250..123c3777f6 100644
--- a/c2rust-transpile/src/c_ast/iterators.rs
+++ b/c2rust-transpile/src/c_ast/iterators.rs
@@ -171,11 +171,11 @@ fn immediate_decl_children(kind: &CDeclKind) -> Vec<SomeId> {
         }
         Enum {
             ref variants,
-            integral_type,
+            underlying_type_id,
             ..
         } => {
             let mut res: Vec<SomeId> = variants.iter().map(|&x| x.into()).collect();
-            if let Some(qty) = integral_type {
+            if let Some(qty) = underlying_type_id {
                 res.push(qty.ctype.into());
             }
             res
diff --git a/c2rust-transpile/src/c_ast/mod.rs b/c2rust-transpile/src/c_ast/mod.rs
index fb1e73a1e3..2968ced03a 100644
--- a/c2rust-transpile/src/c_ast/mod.rs
+++ b/c2rust-transpile/src/c_ast/mod.rs
@@ -530,7 +530,7 @@ impl TypedAstContext {
                 Struct { fields: None, .. }
                     | Union { fields: None, .. }
                     | Enum {
-                        integral_type: None,
+                        underlying_type_id: None,
                         ..
                     }
             )
@@ -1832,7 +1832,7 @@ pub enum CDeclKind {
     Enum {
         name: Option<String>,
         variants: Vec<CEnumConstantId>,
-        integral_type: Option<CQualTypeId>,
+        underlying_type_id: Option<CQualTypeId>,
     },
 
     EnumConstant {
diff --git a/c2rust-transpile/src/cfg/mod.rs b/c2rust-transpile/src/cfg/mod.rs
index 94daca5eb0..e75faac2ac 100644
--- a/c2rust-transpile/src/cfg/mod.rs
+++ b/c2rust-transpile/src/cfg/mod.rs
@@ -2026,7 +2026,7 @@ impl CfgBuilder {
                         .kind;
 
                     if let CTypeKind::Enum(enum_id) = *castee_type_kind {
-                        if target_type_id == translator.enum_integral_type(enum_id) {
+                        if target_type_id == translator.enum_underlying_type(enum_id) {
                             expected_type_id = Some(castee_type_id);
                         }
                     }
diff --git a/c2rust-transpile/src/translator/enums.rs b/c2rust-transpile/src/translator/enums.rs
index 65c81bf884..06529c41d2 100644
--- a/c2rust-transpile/src/translator/enums.rs
+++ b/c2rust-transpile/src/translator/enums.rs
@@ -15,7 +15,7 @@ impl<'c> Translation<'c> {
         &self,
         enum_id: CEnumId,
         span: Span,
-        integral_type: CQualTypeId,
+        underlying_type_id: CQualTypeId,
         variants: &[CEnumConstantId],
     ) -> TranslationResult<ConvertedDecl> {
         let enum_name = &self
@@ -23,8 +23,8 @@ impl<'c> Translation<'c> {
             .borrow()
             .resolve_decl_name(enum_id)
             .expect("Enums should already be renamed");
-        let integral_type_rs = self.convert_type(integral_type.ctype)?;
-        let field = mk().pub_().enum_field(integral_type_rs);
+        let underlying_type_rs = self.convert_type(underlying_type_id.ctype)?;
+        let field = mk().pub_().enum_field(underlying_type_rs);
         let enum_item = mk()
             .span(span)
             .call_attr("derive", vec!["Clone", "Copy", "PartialEq", "Eq"])
@@ -36,6 +36,8 @@ impl<'c> Translation<'c> {
             return Ok(ConvertedDecl::Item(enum_item));
         }
 
+        let underlying_type_kind = &self.ast_context.resolve_type(underlying_type_id.ctype).kind;
+        let underlying_type_is_bool = underlying_type_kind.is_bool();
         let enum_type = mk().ident_ty("Self");
         let constants = variants
             .iter()
@@ -49,7 +51,8 @@ impl<'c> Translation<'c> {
                     enum_constant_id,
                     name,
                 );
-                let (span, init) = self.make_enum_constant_init(enum_constant_id);
+                let (span, init) =
+                    self.make_enum_constant_init(enum_constant_id, underlying_type_is_bool);
                 mk().span(span)
                     .pub_()
                     .const_impl_item(name_rs, enum_type.clone(), init)
@@ -62,14 +65,26 @@ impl<'c> Translation<'c> {
         Ok(ConvertedDecl::Items(vec![enum_item, impl_block]))
     }
 
-    fn make_enum_constant_init(&self, enum_constant_id: CEnumConstantId) -> (Span, Box<Expr>) {
+    fn make_enum_constant_init(
+        &self,
+        enum_constant_id: CEnumConstantId,
+        is_bool: bool,
+    ) -> (Span, Box<Expr>) {
         let value = match self.ast_context[enum_constant_id].kind {
             CDeclKind::EnumConstant { value, .. } => value,
             _ => panic!("{:?} does not point to an enum variant", enum_constant_id),
         };
         let value_rs = match value {
             ConstIntExpr::I(value) => signed_int_expr(value),
-            ConstIntExpr::U(value) => mk().lit_expr(mk().int_unsuffixed_lit(value as u128)),
+            ConstIntExpr::U(value) => {
+                let lit = if is_bool {
+                    mk().bool_lit(value != 0)
+                } else {
+                    mk().int_unsuffixed_lit(value as u128)
+                };
+
+                mk().lit_expr(lit)
+            }
         };
         let enum_id = self.ast_context.parents[&enum_constant_id];
         let init = self.enum_constructor_expr(enum_id, value_rs, true);
@@ -116,16 +131,16 @@ impl<'c> Translation<'c> {
             ));
         }
 
-        // First extract the enum's inner type...
-        val = self.integer_from_enum(val);
+        // First extract the enum's underlying type...
+        val = self.make_enum_to_underlying_cast(val);
 
-        // Cast from the enum's integral type to the expected integral type.
-        let source_cty = self.enum_integral_type(enum_id);
+        // Cast from the underlying type to the expected type.
+        let source_cty = self.enum_underlying_type(enum_id);
         self.make_cast(ctx, source_cty, target_cty, WithStmts::new_val(val))
     }
 
-    /// Gets the inner integral value of an enum value.
-    pub fn integer_from_enum(&self, val: Box<Expr>) -> Box<Expr> {
+    /// Gets the underlying value of an enum value.
+    pub fn make_enum_to_underlying_cast(&self, val: Box<Expr>) -> Box<Expr> {
         mk().anon_field_expr(val, 0)
     }
 
@@ -152,14 +167,14 @@ impl<'c> Translation<'c> {
                 ));
             }
 
-            // Enum-to-enum casts need to be translated via the inner value as an intermediate.
-            val = self.integer_from_enum(val);
-            source_cty = self.enum_integral_type(source_enum_id);
+            // Enum-to-enum casts need to be translated via the underlying value as an intermediate.
+            val = self.make_enum_to_underlying_cast(val);
+            source_cty = self.enum_underlying_type(source_enum_id);
         }
 
-        let enum_integral_type = self.enum_integral_type(enum_id);
+        let underlying_type_id = self.enum_underlying_type(enum_id);
         let mut val = WithStmts::new_val(val);
-        val = self.make_cast(ctx, source_cty, enum_integral_type, val)?;
+        val = self.make_cast(ctx, source_cty, underlying_type_id, val)?;
         val = val.map(|val| self.enum_constructor_expr(enum_id, val, false));
 
         Ok(val)
@@ -172,7 +187,7 @@ impl<'c> Translation<'c> {
             return self.enum_constant_expr(enum_constant_id);
         }
 
-        let underlying_type_id = self.enum_integral_type(enum_id);
+        let underlying_type_id = self.enum_underlying_type(enum_id);
         let value = match self.ast_context.resolve_type(underlying_type_id.ctype).kind {
             CTypeKind::UInt => mk().lit_expr(mk().int_unsuffixed_lit((value as u32) as u128)),
             CTypeKind::ULong => mk().lit_expr(mk().int_unsuffixed_lit((value as u64) as u128)),
@@ -261,14 +276,14 @@ impl<'c> Translation<'c> {
         type_enum_id == constant_enum_id
     }
 
-    pub(crate) fn enum_integral_type(&self, enum_id: CEnumId) -> CQualTypeId {
+    pub(crate) fn enum_underlying_type(&self, enum_id: CEnumId) -> CQualTypeId {
         match self.ast_context[enum_id].kind {
             CDeclKind::Enum {
-                integral_type: Some(integral_type),
+                underlying_type_id: Some(underlying_type_id),
                 ..
-            } => integral_type,
+            } => underlying_type_id,
             _ => panic!(
-                "{:?} does not point to an integral `enum` declaration",
+                "{:?} does not point to a non-extern `enum` declaration",
                 enum_id
             ),
         }
diff --git a/c2rust-transpile/src/translator/mod.rs b/c2rust-transpile/src/translator/mod.rs
index 5a0a6450db..1233f1e3dc 100644
--- a/c2rust-transpile/src/translator/mod.rs
+++ b/c2rust-transpile/src/translator/mod.rs
@@ -2067,7 +2067,7 @@ impl<'c> Translation<'c> {
             Struct { fields: None, .. }
             | Union { fields: None, .. }
             | Enum {
-                integral_type: None,
+                underlying_type_id: None,
                 ..
             } => {
                 self.use_feature("extern_types");
@@ -2110,9 +2110,9 @@ impl<'c> Translation<'c> {
 
             Enum {
                 ref variants,
-                integral_type: Some(integral_type),
+                underlying_type_id: Some(underlying_type_id),
                 ..
-            } => self.convert_enum(decl_id, span, integral_type, variants),
+            } => self.convert_enum(decl_id, span, underlying_type_id, variants),
 
             // EnumConstant is translated as part of Enum.
             EnumConstant { .. } => Ok(ConvertedDecl::NoItem),
@@ -4165,16 +4165,16 @@ impl<'c> Translation<'c> {
                 let target_type_kind = &self.ast_context.resolve_type(target_type_id.ctype).kind;
 
                 if let CTypeKind::Enum(target_enum_id) = *target_type_kind {
-                    let target_integral_type_id = self.enum_integral_type(target_enum_id);
-                    let target_integral_type_kind = &self
+                    let target_underlying_type_id = self.enum_underlying_type(target_enum_id);
+                    let target_underlying_type_kind = &self
                         .ast_context
-                        .resolve_type(target_integral_type_id.ctype)
+                        .resolve_type(target_underlying_type_id.ctype)
                         .kind;
 
                     // We are casting to an enum type, from its underlying integral type.
                     // Skip the cast to the integral type and cast to the enum type directly.
                     if cast_kind == CastKind::IntegralCast
-                        && source_type_kind == target_integral_type_kind
+                        && source_type_kind == target_underlying_type_kind
                     {
                         return true;
                     }
@@ -4191,14 +4191,14 @@ impl<'c> Translation<'c> {
                     }
 
                     let source_enum_id = self.ast_context.parents[&decl_id];
-                    let source_integral_type_id = self.enum_integral_type(source_enum_id);
+                    let source_underlying_type_id = self.enum_underlying_type(source_enum_id);
                     let target_type_resolved_id = self
                         .ast_context
                         .resolve_type_id_no_typedef(target_type_id.ctype);
 
-                    // Likewise, if we are casting to the inner integral type of the enum, then
+                    // Likewise, if we are casting to the underlying type of the enum, then
                     // translate the enum constant directly as that.
-                    if target_type_resolved_id == source_integral_type_id.ctype {
+                    if target_type_resolved_id == source_underlying_type_id.ctype {
                         return true;
                     }
                 }
@@ -4695,7 +4695,7 @@ impl<'c> Translation<'c> {
             }
 
             let val = if ty.is_enum() {
-                self.integer_from_enum(val)
+                self.make_enum_to_underlying_cast(val)
             } else {
                 val
             };
diff --git a/c2rust-transpile/src/translator/operators.rs b/c2rust-transpile/src/translator/operators.rs
index 4c2de512b8..f85193f5fc 100644
--- a/c2rust-transpile/src/translator/operators.rs
+++ b/c2rust-transpile/src/translator/operators.rs
@@ -664,7 +664,7 @@ impl<'c> Translation<'c> {
                 one_type_id = CQualTypeId::new(self.ast_context.type_for_kind(&CTypeKind::Int));
             }
             CTypeKind::Enum(enum_id) => {
-                one_type_id = self.enum_integral_type(enum_id);
+                one_type_id = self.enum_underlying_type(enum_id);
                 compute_lhs_type_id = one_type_id;
                 compute_res_type_id = one_type_id;
             }
diff --git a/c2rust-transpile/src/translator/variadic.rs b/c2rust-transpile/src/translator/variadic.rs
index bacdf9f362..e86286c62b 100644
--- a/c2rust-transpile/src/translator/variadic.rs
+++ b/c2rust-transpile/src/translator/variadic.rs
@@ -192,9 +192,9 @@ impl<'c> Translation<'c> {
 
         match self.ast_context.resolve_type(ty.ctype).kind {
             CTypeKind::Enum(enum_id) => {
-                let integral_type_id = self.enum_integral_type(enum_id);
+                let underlying_type_id = self.enum_underlying_type(enum_id);
                 cast_kind = Some(VaArgCastKind::Enum(enum_id));
-                arg_ty = Some(self.convert_type(integral_type_id.ctype).unwrap());
+                arg_ty = Some(self.convert_type(underlying_type_id.ctype).unwrap());
             }
 
             CTypeKind::Pointer(p) => {