basic support for structures through the IR

src/ir/arbitrary.rs

@@ -9,6 +9,7 @@ use proptest::test_runner::{TestRng, TestRunner};
 use rand::distributions::{Distribution, WeightedIndex};
 use rand::seq::SliceRandom;
 use rand::Rng;
+use std::collections::HashMap;
 use std::str::FromStr;
 
 lazy_static::lazy_static! {
@@ -214,7 +215,10 @@ impl ProgramTree {
             }
         }
 
-        let current = Program { items };
+        let current = Program {
+            items,
+            type_definitions: HashMap::new(),
+        };
 
         ProgramTree { _rng: rng, current }
     }
@@ -328,6 +332,7 @@ fn generate_random_expression(
                         .expect("actually chose type");
                     Expression::Cast(Location::manufactured(), Type::Primitive(*to_type), inner)
                 }
+                Type::Structure(_) => unimplemented!(),
             }
         }
 
@@ -350,6 +355,7 @@ fn generate_random_expression(
                         Expression::Primitive(Location::manufactured(), out_type, primop, args)
                     }
                 },
+                Type::Structure(_) => unimplemented!(),
             }
         }