diff --git a/crates/aiken-lang/Cargo.toml b/crates/aiken-lang/Cargo.toml
index a443df3c..5b2ccafa 100644
--- a/crates/aiken-lang/Cargo.toml
+++ b/crates/aiken-lang/Cargo.toml
@@ -11,7 +11,7 @@ authors = [
     "Kasey White <kwhitemsg@gmail.com>",
     "KtorZ <matthias.benkort@gmail.com>",
 ]
-rust-version = "1.70.0"
+rust-version = "1.80.0"
 build = "build.rs"
 
 [dependencies]
diff --git a/crates/aiken-lang/src/builtins.rs b/crates/aiken-lang/src/builtins.rs
index 9419ee83..774081e8 100644
--- a/crates/aiken-lang/src/builtins.rs
+++ b/crates/aiken-lang/src/builtins.rs
@@ -12,6 +12,7 @@ use crate::{
     },
     IdGenerator,
 };
+use std::{collections::BTreeSet, sync::LazyLock};
 
 use indexmap::IndexMap;
 use std::{collections::HashMap, rc::Rc};
@@ -25,6 +26,16 @@ use uplc::{
 pub const PRELUDE: &str = "aiken";
 pub const BUILTIN: &str = "aiken/builtin";
 
+pub static INTERNAL_FUNCTIONS: LazyLock<BTreeSet<&'static str>> = LazyLock::new(|| {
+    let mut set = BTreeSet::new();
+    set.insert("diagnostic");
+    set.insert("do_from_int");
+    set.insert("encode_base16");
+    set.insert("enumerate");
+    set.insert("from_int");
+    set
+});
+
 /// Build a prelude that can be injected
 /// into a compiler pipeline
 pub fn prelude(id_gen: &IdGenerator) -> TypeInfo {
diff --git a/crates/aiken-lang/src/tipo/environment.rs b/crates/aiken-lang/src/tipo/environment.rs
index 6473ce91..3a2cd2f2 100644
--- a/crates/aiken-lang/src/tipo/environment.rs
+++ b/crates/aiken-lang/src/tipo/environment.rs
@@ -796,8 +796,7 @@ impl<'a> Environment<'a> {
         self.module_types
             .keys()
             .filter_map(|t| {
-                // Avoid leaking special internal types such as __ScriptContext or
-                // __ScriptPurpose.
+                // Avoid leaking special internal types in error hints.
                 if t.starts_with("__") {
                     None
                 } else {
@@ -811,6 +810,9 @@ impl<'a> Environment<'a> {
         self.scope
             .keys()
             .filter(|&t| PIPE_VARIABLE != t)
+            // Avoid leaking internal functions in error hints.
+            .filter(|&t| !crate::builtins::INTERNAL_FUNCTIONS.contains(t.as_str()))
+            .filter(|&t| !t.starts_with("__") && !TypeConstructor::might_be(t))
             .map(|t| t.to_string())
             .collect()
     }
@@ -818,7 +820,9 @@ impl<'a> Environment<'a> {
     pub fn local_constructor_names(&self) -> Vec<String> {
         self.scope
             .keys()
-            .filter(|&t| t.chars().next().unwrap_or_default().is_uppercase())
+            // Avoid leaking internal constructors in error hints.
+            .filter(|&t| !t.starts_with("__"))
+            .filter(|&t| TypeConstructor::might_be(t))
             .map(|t| t.to_string())
             .collect()
     }