diff --git a/src/output/interfaces.rs b/src/output/interfaces.rs
index ea25fd8e..ff5677f4 100644
--- a/src/output/interfaces.rs
+++ b/src/output/interfaces.rs
@@ -16,7 +16,11 @@ impl CodeWriter for InterfaceMap {
                     false,
                     |fmt| {
                         for (name, value) in ifaces {
-                            writeln!(fmt, "public const nint {} = {:#X};", name, value)?;
+                            if *value > i32::MAX as u64 {
+                                writeln!(fmt, "public static readonly nint {} = unchecked((nint){:#X});", name, value)?;
+                            } else {
+                                writeln!(fmt, "public const nint {} = {:#X};", name, value)?;
+                            };
                         }
 
                         Ok(())
diff --git a/src/output/schemas.rs b/src/output/schemas.rs
index 4a6b0ac1..e665a3be 100644
--- a/src/output/schemas.rs
+++ b/src/output/schemas.rs
@@ -41,7 +41,13 @@ impl CodeWriter for SchemaMap {
                                         .members
                                         .iter()
                                         .map(|member| {
-                                            format!("{} = {:#X}", member.name, member.value)
+                                            let hex = format!("{:#X}", member.value);
+                                            let cast = if member.value == -1 {
+                                                format!("unchecked(({})-1)", type_name)
+                                            } else {
+                                                format!("{}", hex)
+                                            };
+                                            format!("{} = {}", member.name, cast)
                                         })
                                         .collect::<Vec<_>>()
                                         .join(",\n");