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fix(tree-sitter): add interface/type alias/as cast support, fix ternary scanner bug #1303

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fix(tree-sitter): add interface/type alias/as cast support, fix ternary scanner bug #1303

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fix(tree-sitter): add interface/type alias/as cast support, fix terna…
Jun 20, 2026
d5cc7c2
fix(tree-sitter): add interface/type alias/as cast support, fix terna…
Jun 20, 2026
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104 changes: 97 additions & 7 deletions grammars/tree-sitter/grammar.js
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Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,10 @@ module.exports = grammar({
$._jsx_statement_container_output,
],

precedences: ($) => [
['call', 'ternary', $.arrow_function],
],

word: ($) => $.identifier,

conflicts: ($) => [
Expand Down Expand Up @@ -97,6 +101,9 @@ module.exports = grammar({
[$.method_definition, $.property_signature],
[$.required_parameter, $.primary_expression, $.type, $.type_identifier],
[$.pattern, $.primary_expression, $.type, $.type_identifier],
[$.as_expression, $.primary_expression],
[$.as_expression, $.type, $.type_identifier],
[$.array_pattern, $.primary_expression],
[$.primary_expression, $.jsx_element_name, $.type_parameter],
[$.spread_element, $.jsx_expression],
[$.if_statement],
Expand All @@ -118,6 +125,13 @@ module.exports = grammar({
[$.declaration, $.jsx_statement_container],
[$.jsx_statement_container, $.object],
[$.jsx_try_expression],
[$.type, $.type_identifier, $.generic_type],
[$.type, $.type_identifier, $.nested_type_identifier],
[$.type, $.generic_type],
[$.type, $.nested_type_identifier],
[$._type_annotation, $.array_type],
[$.empty_statement, $.object_type],
[$.call_expression, $.ternary_expression],

@cursor cursor Bot Jun 20, 2026

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Missing cast in statement expressions

Medium Severity

This commit adds as_expression to the general expression rule but not to _expression_statement_expression or the @{} container expression-statement choice. Top-level or container statements like value as Type; therefore fail to parse as casts unless wrapped in parentheses, unlike other TypeScript contexts that use expression.

Additional Locations (1)
Fix in Cursor Fix in Web

Reviewed by Cursor Bugbot for commit d5cc7c2. Configure here.

],

rules: {
Expand Down Expand Up @@ -395,6 +409,8 @@ module.exports = grammar({
$.class_declaration,
$.lexical_declaration,
$.variable_declaration,
$.interface_declaration,
$.type_alias_declaration,
),

fragment_declaration: ($) =>
Expand Down Expand Up @@ -810,7 +826,13 @@ module.exports = grammar({
array_pattern: ($) =>
seq(
'[',
commaSep(choice($.pattern, $.assignment_pattern, $.rest_pattern)),
commaSep(choice(
$.pattern,
$.assignment_pattern,
$.rest_pattern,
$.member_expression,
$.subscript_expression,
)),
optional(','),
']',
),
Expand All @@ -832,6 +854,7 @@ module.exports = grammar({
$.new_expression,
$.yield_expression,
$.parenthesized_expression,
$.as_expression,
),

primary_expression: ($) =>
Expand Down Expand Up @@ -926,10 +949,10 @@ module.exports = grammar({

ternary_expression: ($) =>
prec.right(
PREC.TERNARY,
'ternary',
seq(
field('condition', $.expression),
$._ternary_qmark,
alias($._ternary_qmark, '?'),
field('consequence', $.expression),
':',
field('alternative', $.expression),
Expand Down Expand Up @@ -1008,7 +1031,7 @@ module.exports = grammar({

call_expression: ($) =>
prec(
PREC.CALL,
'call',
seq(
field('function', choice($.expression, $.import)),
field('arguments', choice($.arguments, $.template_string)),
Expand All @@ -1020,8 +1043,9 @@ module.exports = grammar({
PREC.NEW,
seq(
'new',
field('constructor', $.primary_expression),
optional(field('arguments', $.arguments)),
field('constructor', $.primary_expression),
optional(field('type_arguments', $.type_arguments)),
optional(field('arguments', $.arguments)),
),
),

Expand Down Expand Up @@ -1355,7 +1379,7 @@ module.exports = grammar({

type_arguments: ($) => seq('<', commaSep1($.type), optional(','), '>'),

object_type: ($) => seq('{', commaSep($.property_signature), optional(','), '}'),
object_type: ($) => seq('{', sepBy($.property_signature, choice(';', ',')), optional(choice(';', ',')), '}'),

property_signature: ($) =>
seq(optional('readonly'), field('name', $.property_name), optional('?'), $._type_annotation),
Expand All @@ -1374,12 +1398,78 @@ module.exports = grammar({

parenthesized_type: ($) => seq('(', $.type, ')'),

// TypeScript interface declarations
interface_declaration: ($) =>
seq(
'interface',
field('name', $.type_identifier),
optional(field('type_parameters', $.type_parameters)),
optional(seq('extends', commaSep1($.type))),
field('body', $.interface_body),
),

interface_body: ($) =>
seq(
'{',
repeat(seq(
choice($.property_signature, $.method_signature, $.index_signature),
optional(choice($._semicolon, ',')),
)),
'}',
),


method_signature: ($) =>
seq(
field('name', $.property_name),
optional('?'),
optional(field('type_parameters', $.type_parameters)),
field('parameters', $.formal_parameters),
optional($._type_annotation),
),

index_signature: ($) =>
seq(
'[',
field('name', $.identifier),
':',
field('index_type', $.type),
']',
$._type_annotation,
),

// TypeScript type alias declarations
type_alias_declaration: ($) =>
seq(
'type',
field('name', $.type_identifier),
optional(field('type_parameters', $.type_parameters)),
'=',
field('value', $.type),
$._semicolon,
),

// TypeScript 'as' type assertion / cast
as_expression: ($) =>
prec.left(
PREC.REL,
seq(
field('expression', $.expression),
'as',
field('type', choice($.type, 'const')),
),
),

initializer: ($) => seq('=', choice($.expression, $.style_element)),

_semicolon: ($) => choice($._automatic_semicolon, ';'),
},
});

function sepBy(rule, sep) {
return optional(seq(rule, repeat(seq(sep, rule))));
}

function commaSep(rule) {
return optional(commaSep1(rule));
}
Expand Down
5 changes: 1 addition & 4 deletions grammars/tree-sitter/src/scanner.c
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Original file line number Diff line number Diff line change
Expand Up @@ -278,10 +278,7 @@ bool tree_sitter_ripple_external_scanner_scan(void *payload, TSLexer *lexer,

if (valid_symbols[AUTOMATIC_SEMICOLON]) {
bool ret = scan_automatic_semicolon(lexer);
if (!ret && !valid_symbols[TERNARY_QMARK] && lexer->lookahead == '?') {
return false;
}
return ret;
if (ret) return true;
}

if (valid_symbols[TERNARY_QMARK]) {
Expand Down