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Discrepancy in parsing of for statement condition #351
Description
The following piece of code is valid but it is parsed incorrectly:
for (let i = 0; i < 10; i++) {}Here's a link to the TypeScript Playground showing that the snippet above is valid JavaScript or TypeScript:
https://www.typescriptlang.org/play/?#code/GYewTgBAFANgpgFwgSwgXggBgNwogHggEYcUBqMgSggG8BfIA
The output of tree-sitter parse is the following:
(program [0, 0] - [1, 0]
(for_statement [0, 0] - [0, 31]
initializer: (lexical_declaration [0, 5] - [0, 15]
(variable_declarator [0, 9] - [0, 14]
name: (identifier [0, 9] - [0, 10])
value: (number [0, 13] - [0, 14])))
condition: (binary_expression [0, 16] - [0, 22]
left: (identifier [0, 16] - [0, 17])
right: (number [0, 20] - [0, 22]))
increment: (update_expression [0, 24] - [0, 27]
argument: (identifier [0, 24] - [0, 25]))
body: (statement_block [0, 29] - [0, 31])))
However, tree-sitter playground generates the following tree:
program [0, 0] - [1, 0]
for_statement [0, 0] - [0, 31]
for [0, 0] - [0, 3]
( [0, 4] - [0, 5]
initializer: lexical_declaration [0, 5] - [0, 15]
kind: let [0, 5] - [0, 8]
variable_declarator [0, 9] - [0, 14]
name: identifier [0, 9] - [0, 10]
= [0, 11] - [0, 12]
value: number [0, 13] - [0, 14]
; [0, 14] - [0, 15]
condition: expression_statement [0, 16] - [0, 23]
binary_expression [0, 16] - [0, 22]
left: identifier [0, 16] - [0, 17]
operator: < [0, 18] - [0, 19]
right: number [0, 20] - [0, 22]
; [0, 22] - [0, 23]
increment: update_expression [0, 24] - [0, 27]
argument: identifier [0, 24] - [0, 25]
operator: ++ [0, 25] - [0, 27]
) [0, 27] - [0, 28]
body: statement_block [0, 29] - [0, 31]
{ [0, 29] - [0, 30]
} [0, 30] - [0, 31]
In the playground tree, the condition i < 10; is wrapped inside an expression_statement, whereas in the tree generated by tree-sitter parse, it is directly a binary_expression. The expected behavior is that the tree-sitter parse output should match the playground tree, ensuring the condition is correctly wrapped inside an expression_statement.
Activity
jackschu commentedon May 27, 2025
I think maybe you just has the 'show anonymous nodes' button selected in the playground and that fully explains the difference. I think this should be closed.