2 files changed, 9 insertions, 4 deletions

diff --git a/boot/lex.c b/boot/lex.c
index 0fc6ed1..c66d160 100644
--- a/boot/lex.c
+++ b/boot/lex.c
@@ -275,7 +275,8 @@ token_kind_to_string(enum Token_Kind kind)
         return "ASSIGN_RIGHT_SHIFT";
 
     default:
-        return "";
+        failure("unknown token kind passed to `token_kind_to_string`");
+        return nil;
     }
 }
 
diff --git a/boot/tree.c b/boot/tree.c
index e6c5b78..593103a 100644
--- a/boot/tree.c
+++ b/boot/tree.c
@@ -40,7 +40,8 @@ unary_operation_to_string(enum Unary_Operation operation)
         return "~";
 
     default:
-        return "unknown";
+        failure("unexpected unary operation passed to `unary_operation_to_string`");
+        return nil;
     }
 }
 
@@ -212,6 +213,7 @@ binary_operation_precedence(enum Binary_Operation operation)
         // strongest
 
     default:
+        failure("unexpected binary operation passed to `binary_operation_precedence`");
         return 0;
     }
 }
@@ -316,7 +318,8 @@ binary_operation_to_string(enum Binary_Operation operation)
         return ">>=";
 
     default:
-        return "unknown";
+        failure("unexpected binary operation passed to `binary_operation_to_string`");
+        return nil;
     }
 }
 
@@ -511,6 +514,7 @@ expression_print(const struct Expression* expression)
         printf(")");
         break;
     default:
+        failure("unexpected expression kind passed to `expression_print`");
         break;
     }
     printf(")");
@@ -572,7 +576,7 @@ statement_print(const struct Statement* statement)
         break;
     }
     default:
-        printf("unknown");
+        failure("unexpected statement kind passed to `statement_print`");
         break;
     }
     printf(")");