diff --git a/typify-impl/src/value.rs b/typify-impl/src/value.rs
index 4e9e13c8..ac7bfc60 100644
--- a/typify-impl/src/value.rs
+++ b/typify-impl/src/value.rs
@@ -437,8 +437,8 @@ fn value_for_struct_props(
             }
 
             let flat_value = type_entry.output_value(type_space, &extra_value, scope)?;
-            let name = &prop.name;
-            Some(quote! { #name: #flat_value })
+            let name_ident = format_ident!("{}", &prop.name);
+            Some(quote! { #name_ident: #flat_value })
         }
         _ => None,
     });
diff --git a/typify/tests/schemas/flatten-default.json b/typify/tests/schemas/flatten-default.json
new file mode 100644
index 00000000..4111d633
--- /dev/null
+++ b/typify/tests/schemas/flatten-default.json
@@ -0,0 +1,23 @@
+{
+  "$comment": "regression test: a default value for a struct type with a flattened property must produce a valid Rust identifier for the flattened field",
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "title": "Container",
+  "type": "object",
+  "properties": {
+    "thing": {
+      "type": "object",
+      "properties": {
+        "id": {
+          "type": "string"
+        }
+      },
+      "additionalProperties": {
+        "type": "string"
+      },
+      "default": {
+        "id": "abc",
+        "extra_key": "extra_value"
+      }
+    }
+  }
+}
diff --git a/typify/tests/schemas/flatten-default.rs b/typify/tests/schemas/flatten-default.rs
new file mode 100644
index 00000000..33261102
--- /dev/null
+++ b/typify/tests/schemas/flatten-default.rs
@@ -0,0 +1,226 @@
+#![deny(warnings)]
+#[doc = r" Error types."]
+pub mod error {
+    #[doc = r" Error from a `TryFrom` or `FromStr` implementation."]
+    pub struct ConversionError(::std::borrow::Cow<'static, str>);
+    impl ::std::error::Error for ConversionError {}
+    impl ::std::fmt::Display for ConversionError {
+        fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> Result<(), ::std::fmt::Error> {
+            ::std::fmt::Display::fmt(&self.0, f)
+        }
+    }
+    impl ::std::fmt::Debug for ConversionError {
+        fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> Result<(), ::std::fmt::Error> {
+            ::std::fmt::Debug::fmt(&self.0, f)
+        }
+    }
+    impl From<&'static str> for ConversionError {
+        fn from(value: &'static str) -> Self {
+            Self(value.into())
+        }
+    }
+    impl From<String> for ConversionError {
+        fn from(value: String) -> Self {
+            Self(value.into())
+        }
+    }
+}
+#[doc = "`Container`"]
+#[doc = r""]
+#[doc = r" <details><summary>JSON schema</summary>"]
+#[doc = r""]
+#[doc = r" ```json"]
+#[doc = "{"]
+#[doc = "  \"title\": \"Container\","]
+#[doc = "  \"type\": \"object\","]
+#[doc = "  \"properties\": {"]
+#[doc = "    \"thing\": {"]
+#[doc = "      \"default\": {"]
+#[doc = "        \"extra_key\": \"extra_value\","]
+#[doc = "        \"id\": \"abc\""]
+#[doc = "      },"]
+#[doc = "      \"type\": \"object\","]
+#[doc = "      \"properties\": {"]
+#[doc = "        \"id\": {"]
+#[doc = "          \"type\": \"string\""]
+#[doc = "        }"]
+#[doc = "      },"]
+#[doc = "      \"additionalProperties\": {"]
+#[doc = "        \"type\": \"string\""]
+#[doc = "      }"]
+#[doc = "    }"]
+#[doc = "  },"]
+#[doc = "  \"$comment\": \"regression test: a default value for a struct type with a flattened property must produce a valid Rust identifier for the flattened field\""]
+#[doc = "}"]
+#[doc = r" ```"]
+#[doc = r" </details>"]
+#[derive(:: serde :: Deserialize, :: serde :: Serialize, Clone, Debug)]
+pub struct Container {
+    #[serde(default, skip_serializing_if = "::std::option::Option::is_none")]
+    pub thing: ::std::option::Option<ContainerThing>,
+}
+impl ::std::default::Default for Container {
+    fn default() -> Self {
+        Self {
+            thing: Default::default(),
+        }
+    }
+}
+impl Container {
+    pub fn builder() -> builder::Container {
+        Default::default()
+    }
+}
+#[doc = "`ContainerThing`"]
+#[doc = r""]
+#[doc = r" <details><summary>JSON schema</summary>"]
+#[doc = r""]
+#[doc = r" ```json"]
+#[doc = "{"]
+#[doc = "  \"default\": {"]
+#[doc = "    \"extra_key\": \"extra_value\","]
+#[doc = "    \"id\": \"abc\""]
+#[doc = "  },"]
+#[doc = "  \"type\": \"object\","]
+#[doc = "  \"properties\": {"]
+#[doc = "    \"id\": {"]
+#[doc = "      \"type\": \"string\""]
+#[doc = "    }"]
+#[doc = "  },"]
+#[doc = "  \"additionalProperties\": {"]
+#[doc = "    \"type\": \"string\""]
+#[doc = "  }"]
+#[doc = "}"]
+#[doc = r" ```"]
+#[doc = r" </details>"]
+#[derive(:: serde :: Deserialize, :: serde :: Serialize, Clone, Debug)]
+pub struct ContainerThing {
+    #[serde(default, skip_serializing_if = "::std::option::Option::is_none")]
+    pub id: ::std::option::Option<::std::string::String>,
+    #[serde(flatten)]
+    pub extra: ::std::collections::HashMap<::std::string::String, ::std::string::String>,
+}
+impl ::std::default::Default for ContainerThing {
+    fn default() -> Self {
+        ContainerThing {
+            id: ::std::option::Option::Some("abc".to_string()),
+            extra: [("extra_key".to_string(), "extra_value".to_string())]
+                .into_iter()
+                .collect(),
+        }
+    }
+}
+impl ContainerThing {
+    pub fn builder() -> builder::ContainerThing {
+        Default::default()
+    }
+}
+#[doc = r" Types for composing complex structures."]
+pub mod builder {
+    #[derive(Clone, Debug)]
+    pub struct Container {
+        thing: ::std::result::Result<
+            ::std::option::Option<super::ContainerThing>,
+            ::std::string::String,
+        >,
+    }
+    impl ::std::default::Default for Container {
+        fn default() -> Self {
+            Self {
+                thing: Ok(Default::default()),
+            }
+        }
+    }
+    impl Container {
+        pub fn thing<T>(mut self, value: T) -> Self
+        where
+            T: ::std::convert::TryInto<::std::option::Option<super::ContainerThing>>,
+            T::Error: ::std::fmt::Display,
+        {
+            self.thing = value
+                .try_into()
+                .map_err(|e| format!("error converting supplied value for thing: {e}"));
+            self
+        }
+    }
+    impl ::std::convert::TryFrom<Container> for super::Container {
+        type Error = super::error::ConversionError;
+        fn try_from(
+            value: Container,
+        ) -> ::std::result::Result<Self, super::error::ConversionError> {
+            Ok(Self {
+                thing: value.thing?,
+            })
+        }
+    }
+    impl ::std::convert::From<super::Container> for Container {
+        fn from(value: super::Container) -> Self {
+            Self {
+                thing: Ok(value.thing),
+            }
+        }
+    }
+    #[derive(Clone, Debug)]
+    pub struct ContainerThing {
+        id: ::std::result::Result<
+            ::std::option::Option<::std::string::String>,
+            ::std::string::String,
+        >,
+        extra: ::std::result::Result<
+            ::std::collections::HashMap<::std::string::String, ::std::string::String>,
+            ::std::string::String,
+        >,
+    }
+    impl ::std::default::Default for ContainerThing {
+        fn default() -> Self {
+            Self {
+                id: Ok(Default::default()),
+                extra: Err("no value supplied for extra".to_string()),
+            }
+        }
+    }
+    impl ContainerThing {
+        pub fn id<T>(mut self, value: T) -> Self
+        where
+            T: ::std::convert::TryInto<::std::option::Option<::std::string::String>>,
+            T::Error: ::std::fmt::Display,
+        {
+            self.id = value
+                .try_into()
+                .map_err(|e| format!("error converting supplied value for id: {e}"));
+            self
+        }
+        pub fn extra<T>(mut self, value: T) -> Self
+        where
+            T: ::std::convert::TryInto<
+                ::std::collections::HashMap<::std::string::String, ::std::string::String>,
+            >,
+            T::Error: ::std::fmt::Display,
+        {
+            self.extra = value
+                .try_into()
+                .map_err(|e| format!("error converting supplied value for extra: {e}"));
+            self
+        }
+    }
+    impl ::std::convert::TryFrom<ContainerThing> for super::ContainerThing {
+        type Error = super::error::ConversionError;
+        fn try_from(
+            value: ContainerThing,
+        ) -> ::std::result::Result<Self, super::error::ConversionError> {
+            Ok(Self {
+                id: value.id?,
+                extra: value.extra?,
+            })
+        }
+    }
+    impl ::std::convert::From<super::ContainerThing> for ContainerThing {
+        fn from(value: super::ContainerThing) -> Self {
+            Self {
+                id: Ok(value.id),
+                extra: Ok(value.extra),
+            }
+        }
+    }
+}
+fn main() {}