Correct errors for invalid retry

Author: kddnewton

config.yml

@@ -138,6 +138,9 @@ errors:
   - INVALID_PRINTABLE_CHARACTER
   - INVALID_VARIABLE_GLOBAL
   - INVALID_VARIABLE_GLOBAL_3_3_0
+  - INVALID_RETRY_AFTER_ELSE
+  - INVALID_RETRY_AFTER_ENSURE
+  - INVALID_RETRY_WITHOUT_RESCUE
   - IT_NOT_ALLOWED_NUMBERED
   - IT_NOT_ALLOWED_ORDINARY
   - LAMBDA_OPEN

src/prism.c

@@ -15763,6 +15763,75 @@ parse_block_exit(pm_parser_t *parser, pm_token_t *token) {
     }
 }
 
+/**
+ * Ensures that the current retry token is valid in the current context.
+ */
+static void
+parse_retry(pm_parser_t *parser, pm_token_t *token) {
+    pm_context_node_t *context_node = parser->current_context;
+
+    while (context_node != NULL) {
+        switch (context_node->context) {
+            case PM_CONTEXT_RESCUE:
+            case PM_CONTEXT_RESCUE_DEF:
+                // These are the good cases. We're allowed to have a retry here.
+                return;
+            case PM_CONTEXT_CLASS:
+            case PM_CONTEXT_DEF:
+            case PM_CONTEXT_DEF_PARAMS:
+            case PM_CONTEXT_MAIN:
+            case PM_CONTEXT_MODULE:
+            case PM_CONTEXT_PREEXE:
+            case PM_CONTEXT_SCLASS:
+                // These are the bad cases. We're not allowed to have a retry in
+                // these contexts.
+                PM_PARSER_ERR_TOKEN_FORMAT_CONTENT(parser, *token, PM_ERR_INVALID_RETRY_WITHOUT_RESCUE);
+                return;
+            case PM_CONTEXT_RESCUE_ELSE_DEF:
+            case PM_CONTEXT_RESCUE_ELSE:
+                // These are also bad cases, but with a more specific error
+                // message indicating the else.
+                PM_PARSER_ERR_TOKEN_FORMAT_CONTENT(parser, *token, PM_ERR_INVALID_RETRY_AFTER_ELSE);
+                return;
+            case PM_CONTEXT_ENSURE:
+            case PM_CONTEXT_ENSURE_DEF:
+                // These are also bad cases, but with a more specific error
+                // message indicating the ensure.
+                PM_PARSER_ERR_TOKEN_FORMAT_CONTENT(parser, *token, PM_ERR_INVALID_RETRY_AFTER_ENSURE);
+                return;
+            case PM_CONTEXT_NONE:
+                // This case should never happen.
+                assert(false && "unreachable");
+                break;
+            case PM_CONTEXT_BEGIN:
+            case PM_CONTEXT_BLOCK_BRACES:
+            case PM_CONTEXT_BLOCK_KEYWORDS:
+            case PM_CONTEXT_CASE_IN:
+            case PM_CONTEXT_CASE_WHEN:
+            case PM_CONTEXT_DEFAULT_PARAMS:
+            case PM_CONTEXT_ELSE:
+            case PM_CONTEXT_ELSIF:
+            case PM_CONTEXT_EMBEXPR:
+            case PM_CONTEXT_FOR_INDEX:
+            case PM_CONTEXT_FOR:
+            case PM_CONTEXT_IF:
+            case PM_CONTEXT_LAMBDA_BRACES:
+            case PM_CONTEXT_LAMBDA_DO_END:
+            case PM_CONTEXT_PARENS:
+            case PM_CONTEXT_POSTEXE:
+            case PM_CONTEXT_PREDICATE:
+            case PM_CONTEXT_UNLESS:
+            case PM_CONTEXT_UNTIL:
+            case PM_CONTEXT_WHILE:
+                // In these contexts we should continue walking up the list of
+                // contexts.
+                break;
+        }
+
+        context_node = context_node->prev;
+    }
+}
+
 /**
  * Parse an expression that begins with the previous node that we just lexed.
  */
@@ -17355,6 +17424,7 @@ parse_expression_prefix(pm_parser_t *parser, pm_binding_power_t binding_power, b
             parser_lex(parser);
             return (pm_node_t *) pm_redo_node_create(parser, &parser->previous);
         case PM_TOKEN_KEYWORD_RETRY:
+            parse_retry(parser, &parser->current);
             parser_lex(parser);
             return (pm_node_t *) pm_retry_node_create(parser, &parser->previous);
         case PM_TOKEN_KEYWORD_SELF:

templates/src/diagnostic.c.erb

@@ -219,6 +219,9 @@ static const pm_diagnostic_data_t diagnostic_messages[PM_DIAGNOSTIC_ID_MAX] = {
     [PM_ERR_INVALID_MULTIBYTE_ESCAPE]           = { "invalid multibyte escape: /%.*s/", PM_ERROR_LEVEL_SYNTAX },
     [PM_ERR_INVALID_PRINTABLE_CHARACTER]        = { "invalid character `%c`", PM_ERROR_LEVEL_SYNTAX },
     [PM_ERR_INVALID_PERCENT]                    = { "invalid `%` token", PM_ERROR_LEVEL_SYNTAX }, // TODO WHAT?
+    [PM_ERR_INVALID_RETRY_AFTER_ELSE]           = { "Invalid retry after else", PM_ERROR_LEVEL_SYNTAX },
+    [PM_ERR_INVALID_RETRY_AFTER_ENSURE]         = { "Invalid retry after ensure", PM_ERROR_LEVEL_SYNTAX },
+    [PM_ERR_INVALID_RETRY_WITHOUT_RESCUE]       = { "Invalid retry without rescue", PM_ERROR_LEVEL_SYNTAX },
     [PM_ERR_INVALID_VARIABLE_GLOBAL_3_3_0]      = { "`%.*s' is not allowed as a global variable name", PM_ERROR_LEVEL_SYNTAX },
     [PM_ERR_INVALID_VARIABLE_GLOBAL]            = { "'%.*s' is not allowed as a global variable name", PM_ERROR_LEVEL_SYNTAX },
     [PM_ERR_IT_NOT_ALLOWED_NUMBERED]            = { "`it` is not allowed when an numbered parameter is defined", PM_ERROR_LEVEL_SYNTAX },