Fix bug that disabled the creation of recursive functions

...oops.

The introduction and usage of `Compiler::emit_assign` deferred the
declaration of a name to be declared *after* the RHS of an assignment
had been evaluated. Normally, this is not a problem because you
shouldn't be using the LHS that you're assigning in the RHS
expression... except when you're defining a function.

This has been enabled for functions *only* and well be enabled for other
types as necessary.

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

src/compiler.rs

@@ -588,6 +588,22 @@ impl StmtVisitor for Compiler<'_> {
         match stmt.op.kind {
             // normal assignment
             TokenKind::Eq => {
+                // Insert the name beforehand, but only if we're compiling a function
+                // I think this is the only instance where we care about inserting a name before
+                // it's used
+                if stmt
+                    .rhs
+                    .as_any_ref()
+                    .downcast_ref::<FunctionExpr>()
+                    .is_some()
+                {
+                    if self.is_global_scope() {
+                        self.insert_global(name)?;
+                    } else if self.get_local(name).is_none() {
+                        self.insert_local(name.to_string())?;
+                    }
+                }
+
                 // compile RHS
                 self.compile_expr(&stmt.rhs)?;