fix a crash in data def compilation

Author: kaikalii

src/compile/data.rs

@@ -277,10 +277,11 @@ impl Compiler {
 
         let mut variant_index = 0;
         if data.variant {
-            let module_scope = self.higher_scopes.last_mut().unwrap_or(&mut self.scope);
-            variant_index = module_scope.data_variants.len();
-            let name = data.name.as_ref().unwrap().value.clone();
-            module_scope.data_variants.insert(name);
+            if let Some(name) = data.name.as_ref() {
+                let module_scope = self.higher_scopes.last_mut().unwrap_or(&mut self.scope);
+                variant_index = module_scope.data_variants.len();
+                module_scope.data_variants.insert(name.value.clone());
+            }
         }
 
         // Make getters

tests_special/error.ua

@@ -182,4 +182,6 @@ F ← |0.1000 ⍢(F F F|1)
 
 °⊸(⌝⤸0) ⇡3 °△3_3
 
-⊥1 5
+⊥1 5
+
+|