From 9ed79984016a1e1423311670a2f913d21e6eaded Mon Sep 17 00:00:00 2001
From: Nilstrieb <48135649+Nilstrieb@users.noreply.github.com>
Date: Fri, 31 Dec 2021 17:00:51 +0100
Subject: [PATCH] fix string interning

---
 src/gc.rs | 29 +++++++++++++++++++++++++----
 test.dil  | 10 +++++++++-
 2 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/src/gc.rs b/src/gc.rs
index 5e1efbd..e5019f9 100644
--- a/src/gc.rs
+++ b/src/gc.rs
@@ -74,10 +74,29 @@ enum HeapObjectKind {
 
 #[derive(Debug)]
 pub struct RtAlloc {
-    symbols: HashSet<NonNull<str>>,
+    symbols: HashSet<NonNullStrWrapper>,
     objects: LinkedList<HeapObject>,
 }
 
+#[derive(Debug)]
+struct NonNullStrWrapper(NonNull<str>);
+
+impl Hash for NonNullStrWrapper {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        // SAFETY: Assume the ptr is valid, same rules as `Gc<T>`
+        unsafe { self.0.as_ref().hash(state) }
+    }
+}
+
+impl PartialEq for NonNullStrWrapper {
+    fn eq(&self, other: &Self) -> bool {
+        // SAFETY: Assume the ptr is valid, same rules as `Gc<T>`
+        unsafe { self.0.as_ref().eq(other.0.as_ref()) }
+    }
+}
+
+impl Eq for NonNullStrWrapper {}
+
 impl RtAlloc {
     /// # Safety
     /// Promise to not forget to mark any roots and to not deref `Gc<T>` after you've dropped me 🥺
@@ -119,10 +138,12 @@ impl RtAlloc {
     pub fn intern_string(&mut self, str: &str) -> Symbol {
         let original_nonnull = NonNull::from(str);
 
-        if let Some(interned) = self.symbols.get(&original_nonnull) {
-            Symbol::new(Gc { ptr: *interned })
+        if let Some(interned) = self.symbols.get(&NonNullStrWrapper(original_nonnull)) {
+            Symbol::new(Gc { ptr: interned.0 })
         } else {
-            Symbol::new(self.alloc_str(str))
+            let allocated = self.alloc_str(str);
+            self.symbols.insert(NonNullStrWrapper(allocated.ptr));
+            Symbol::new(allocated)
         }
     }
 }
diff --git a/test.dil b/test.dil
index 818947d..400067c 100644
--- a/test.dil
+++ b/test.dil
@@ -1 +1,9 @@
-print "Hello World!";
\ No newline at end of file
+let x = 5;
+print x + 4;
+
+let test = x + 6 * 159353.004;
+print test;
+
+if x > test {
+    print "lmao";
+}
\ No newline at end of file