Disallow label in parentheses

Author: kddnewton

config.yml

@@ -272,6 +272,7 @@ errors:
   - UNEXPECTED_BLOCK_ARGUMENT
   - UNEXPECTED_INDEX_BLOCK
   - UNEXPECTED_INDEX_KEYWORDS
+  - UNEXPECTED_LABEL
   - UNEXPECTED_MULTI_WRITE
   - UNEXPECTED_RANGE_OPERATOR
   - UNEXPECTED_SAFE_NAVIGATION

src/prism.c

@@ -347,12 +347,13 @@ static const pm_diagnostic_data_t diagnostic_messages[PM_DIAGNOSTIC_ID_MAX] = {
     [PM_ERR_TERNARY_COLON]                      = { "expected a `:` after the true expression of a ternary operator", PM_ERROR_LEVEL_SYNTAX },
     [PM_ERR_TERNARY_EXPRESSION_FALSE]           = { "expected an expression after `:` in the ternary operator", PM_ERROR_LEVEL_SYNTAX },
     [PM_ERR_TERNARY_EXPRESSION_TRUE]            = { "expected an expression after `?` in the ternary operator", PM_ERROR_LEVEL_SYNTAX },
-    [PM_ERR_UNDEF_ARGUMENT]                     = { "invalid argument being passed to `undef`; expected a bare word, constant, or symbol argument", PM_ERROR_LEVEL_SYNTAX },
     [PM_ERR_UNARY_RECEIVER]                     = { "unexpected %s, expected a receiver for unary `%c`", PM_ERROR_LEVEL_SYNTAX },
     [PM_ERR_UNARY_DISALLOWED]                   = { "unexpected %s; unary calls are not allowed in this context", PM_ERROR_LEVEL_SYNTAX },
+    [PM_ERR_UNDEF_ARGUMENT]                     = { "invalid argument being passed to `undef`; expected a bare word, constant, or symbol argument", PM_ERROR_LEVEL_SYNTAX },
     [PM_ERR_UNEXPECTED_BLOCK_ARGUMENT]          = { "block argument should not be given", PM_ERROR_LEVEL_SYNTAX },
     [PM_ERR_UNEXPECTED_INDEX_BLOCK]             = { "unexpected block arg given in index assignment; blocks are not allowed in index assignment expressions", PM_ERROR_LEVEL_SYNTAX },
     [PM_ERR_UNEXPECTED_INDEX_KEYWORDS]          = { "unexpected keyword arg given in index assignment; keywords are not allowed in index assignment expressions", PM_ERROR_LEVEL_SYNTAX },
+    [PM_ERR_UNEXPECTED_LABEL]                   = { "unexpected label", PM_ERROR_LEVEL_SYNTAX },
     [PM_ERR_UNEXPECTED_MULTI_WRITE]             = { "unexpected multiple assignment; multiple assignment is not allowed in this context", PM_ERROR_LEVEL_SYNTAX },
     [PM_ERR_UNEXPECTED_RANGE_OPERATOR]          = { "unexpected range operator; .. and ... are non-associative and cannot be chained", PM_ERROR_LEVEL_SYNTAX },
     [PM_ERR_UNEXPECTED_SAFE_NAVIGATION]         = { "&. inside multiple assignment destination", PM_ERROR_LEVEL_SYNTAX },

templates/src/diagnostic.c.erb

@@ -0,0 +1,3 @@
+("a":)
+ ^~~~ unexpected label
+

test/prism/errors/label_in_parentheses.txt

@@ -1,3 +1,3 @@
 {x:'y':}
-     ^~ unexpected label terminator, expected a string literal terminator
+   ^~~~ unexpected label
 

test/prism/errors/symbol_in_hash.txt

@@ -1,3 +1,3 @@
 def foo(x:'y':); end
-            ^~ unexpected label terminator, expected a string literal terminator
+          ^~~~ unexpected label