fix uniqueness bug

builtin defs were included twice, which threw off uniqueness inference

compiler/can/src/module.rs

@@ -153,12 +153,8 @@ pub fn canonicalize_module_defs<'a>(
         references.insert(*symbol);
     }
 
-    // Add defs for any referenced builtins.
+    // NOTE previously we inserted builtin defs into the list of defs here
-    for (symbol, def) in builtin_defs(var_store) {
+    // this is now done later, in file.rs.
-        if references.contains(&symbol) {
-            defs.can_defs_by_symbol.insert(symbol, def);
-        }
-    }
 
     match sort_can_defs(&mut env, defs, Output::default()) {
         (Ok(declarations), output) => {

compiler/constrain/src/uniq.rs

@@ -67,6 +67,7 @@ pub fn constrain_decls(
 
     // perform usage analysis on the whole file
     let mut var_usage = VarUsage::default();
+
     for decl in decls.iter().rev() {
         // NOTE: rigids are empty because they are not shared between top-level definitions
         match decl {

examples/quicksort/Quicksort.roc

@@ -1,6 +1,7 @@
 app Quicksort provides [ quicksort ] imports []
 
 quicksort = \originalList ->
+
     quicksortHelp : List (Num a), Int, Int -> List (Num a)
     quicksortHelp = \list, low, high ->
         if low < high then