[checkpoint] Start the switch to type inference.

src/repl.rs

@@ -1,5 +1,4 @@
 use crate::backend::{Backend, BackendError};
-use crate::ir::Program as IR;
 use crate::syntax::{ConstantType, Location, ParserError, Statement};
 use codespan_reporting::diagnostic::Diagnostic;
 use codespan_reporting::files::SimpleFiles;
@@ -155,7 +154,10 @@ impl REPL {
             return Ok(());
         }
 
-        let ir = IR::from(syntax);
+        let ir = crate::syntax::Program {
+            statements: vec![syntax],
+        }
+        .type_infer();
         let name = format!("line{}", line_no);
         let function_id = self.jitter.compile_function(&name, ir)?;
         self.jitter.module.finalize_definitions()?;