fix: Change can_be_main to be recursive

tooling/ast_fuzzer/src/program/mod.rs

@@ -51,7 +51,7 @@
     ctx.set_function_decl(FuncId(1), decl_inner.clone());
     ctx.gen_function(u, FuncId(1))?;
 
     // Parameterless main declaration wrapping the inner "main"
     // function call
     let decl_main = FunctionDeclaration {
         name: "main".into(),
@@ -63,7 +63,7 @@
     };
 
     ctx.set_function_decl(FuncId(0), decl_main);
     ctx.gen_function_with_body(u, FuncId(0), |u, fctx| fctx.gen_body_with_lit_call(u, FuncId(1)))?;
     ctx.rewrite_functions(u)?;
 
     let program = ctx.finalize();
@@ -251,7 +251,7 @@
 
     /// Generate random function body.
     fn gen_function(&mut self, u: &mut Unstructured, id: FuncId) -> arbitrary::Result<()> {
         self.gen_function_with_body(u, id, |u, fctx| fctx.gen_body(u))
     }
 
     /// Generate function with a specified body generator.
@@ -261,7 +261,7 @@
         id: FuncId,
         f: impl Fn(&mut Unstructured, FunctionContext) -> arbitrary::Result<Expression>,
     ) -> arbitrary::Result<()> {
         let fctx = FunctionContext::new(self, id);
         let body = f(u, fctx)?;
         let decl = self.function_decl(id);
         let func = Function {
@@ -425,6 +425,9 @@
                 break;
             }
         }
+        if is_main {
+            println!("TYPE FOR MAIN: {typ}");
+        }
         self.types.insert(typ.clone());
 
         Ok(typ)

tooling/ast_fuzzer/src/program/types.rs

@@ -42,8 +42,11 @@ pub(crate) fn can_be_global(typ: &Type) -> bool {
 /// as well as part of the databus. They are not expected in real programs as they don't do anything useful.
 pub(crate) fn can_be_main(typ: &Type) -> bool {
     match typ {
-        Type::Array(size, _) | Type::String(size) => *size > 0,
-        _ => true,
+        Type::String(size) => *size > 0,
+        Type::Array(size, typ) => *size > 0 && can_be_main(typ),
+        Type::Tuple(types) => types.iter().all(can_be_main),
+        Type::Bool | Type::Field | Type::Integer(_, _) => true,
+        _ => false,
     }
 }