Add some more hardcoded builtin types

src/module/symbol.rs

@@ -547,6 +547,8 @@ define_builtins! {
         1 FLOAT_FLOATINGPOINT: "FloatingPoint" // Float : Num FloatingPoint
         2 FLOAT_AT_FLOATINTPOINT: "@FloatingPoint" // the Float.@FloatingPoint private tag
         3 FLOAT_DIV: "div"
+        4 FLOAT_HIGHEST: "highest"
+        5 FLOAT_LOWEST: "lowest"
     }
     4 BOOL: "Bool" => {
         0 BOOL_BOOL: "Bool" // the Bool.Bool type alias

src/solve.rs

@@ -368,6 +368,24 @@ impl SolvedType {
             ),
         );
 
+        // highest : Float
+        types.insert(
+            Symbol::FLOAT_HIGHEST,
+            (
+                SolvedType::Apply(Symbol::FLOAT_FLOAT, Vec::new()),
+                Region::zero(),
+            ),
+        );
+
+        // lowest : Float
+        types.insert(
+            Symbol::FLOAT_LOWEST,
+            (
+                SolvedType::Apply(Symbol::FLOAT_FLOAT, Vec::new()),
+                Region::zero(),
+            ),
+        );
+
         // List module
 
         // List elem : [ @List elem ]