Add literal conversion based on context at compile time

example/main.nub

@@ -1,5 +1,17 @@
 namespace main
 
+struct Human {
+    age: ^u64
+}
+
 export func main(args: []^string) {
-    sys::call(60, 0)
-}
+    let x = [3]f64
+
+    x[0] = 1
+    x[1.2] = 2
+    x[2] = 3
+
+    c::printf("%d\n", x[0])
+    c::printf("%d\n", x[1])
+    c::printf("%d\n", x[2])
+}