diff --git a/serde_derive/src/de.rs b/serde_derive/src/de.rs
index 778b19346..be4232657 100644
--- a/serde_derive/src/de.rs
+++ b/serde_derive/src/de.rs
@@ -1344,13 +1344,18 @@ fn deserialize_internally_tagged_enum(
 ) -> Fragment {
     let (variants_stmt, variant_visitor) = prepare_enum_variant_enum(variants, cattrs);
 
-    let mut default_variant = quote! { None };
-    for (i, variant) in variants.iter().enumerate() {
-        if variant.attrs.default() {
-            let variant_name = field_i(i);
-            default_variant = quote!{ Some(__Field::#variant_name) };
+    let default_variant = {
+        for (i, variant) in variants.iter().enumerate() {
+            if variant.attrs.default() {
+                return quote_block! {
+                    std::option::Option::Some(__Field::#{field_i(i)})
+                };
+            }
         }
-    }
+        quote_block! {
+            std::option::Option::None
+        }
+    };
 
     // Match arms to extract a variant from a string
     let variant_arms = variants
diff --git a/serde_derive/src/internals/ast.rs b/serde_derive/src/internals/ast.rs
index 739fc8992..cab72c4ff 100644
--- a/serde_derive/src/internals/ast.rs
+++ b/serde_derive/src/internals/ast.rs
@@ -156,10 +156,12 @@ fn enum_from_ast<'a>(
         })
         .collect();
 
-    // Check only one enum arm is marked #[serde(default)]
     let mut has_default = false;
     for variant in &variants {
-        if variant.attrs.default() && has_default {
+        if !variant.attrs.default() {
+            continue;
+        }
+        if has_default {
             cx.error_spanned_by(&variant.ident, "only one variant can be marked as default");
             break;
         }