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perf(parser): optimize around parse_return_type #12095

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Merged
Boshen merged 1 commit into from
Jul 7, 2025
+20 −57
Merged

perf(parser): optimize around parse_return_type #12095

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21 changes: 6 additions & 15 deletions crates/oxc_parser/src/js/arrow.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,6 @@ struct ArrowFunctionHead<'a> {
return_type: Option<Box<'a, TSTypeAnnotation<'a>>>,
r#async: bool,
span: u32,
has_return_colon: bool,
}

impl<'a> ParserImpl<'a> {
Expand Down Expand Up @@ -248,14 +247,7 @@ impl<'a> ParserImpl<'a> {
self.expect(Kind::Arrow);

self.parse_arrow_function_expression_body(
ArrowFunctionHead {
type_parameters: None,
params,
return_type: None,
r#async,
span,
has_return_colon: false,
},
ArrowFunctionHead { type_parameters: None, params, return_type: None, r#async, span },
allow_return_type_in_arrow_function,
)
}
Expand All @@ -279,8 +271,7 @@ impl<'a> ParserImpl<'a> {
self.error(diagnostics::ts_arrow_function_this_parameter(this_param.span));
}

let has_return_colon = self.is_ts && self.at(Kind::Colon);
let return_type = self.parse_ts_return_type_annotation(Kind::Arrow, false);
let return_type = if self.is_ts { self.parse_ts_return_type_annotation() } else { None };

self.ctx = self.ctx.and_await(has_await);

Expand All @@ -290,7 +281,7 @@ impl<'a> ParserImpl<'a> {

self.expect(Kind::Arrow);

ArrowFunctionHead { type_parameters, params, return_type, r#async, span, has_return_colon }
ArrowFunctionHead { type_parameters, params, return_type, r#async, span }
}

/// [ConciseBody](https://tc39.es/ecma262/#prod-ConciseBody)
Expand All @@ -303,7 +294,7 @@ impl<'a> ParserImpl<'a> {
arrow_function_head: ArrowFunctionHead<'a>,
allow_return_type_in_arrow_function: bool,
) -> Expression<'a> {
let ArrowFunctionHead { type_parameters, params, return_type, r#async, span, .. } =
let ArrowFunctionHead { type_parameters, params, return_type, r#async, span } =
arrow_function_head;
let has_await = self.ctx.has_await();
let has_yield = self.ctx.has_yield();
Expand Down Expand Up @@ -362,7 +353,7 @@ impl<'a> ParserImpl<'a> {
return None;
}

let has_return_colon = head.has_return_colon;
let has_return_type = head.return_type.is_some();

let body =
self.parse_arrow_function_expression_body(head, allow_return_type_in_arrow_function);
Expand All @@ -381,7 +372,7 @@ impl<'a> ParserImpl<'a> {
// a() ? (b: number, c?: string): void => d() : e
// is determined by isParenthesizedArrowFunctionExpression to unambiguously
// be an arrow expression, so we allow a return type.
if !allow_return_type_in_arrow_function && has_return_colon {
if !allow_return_type_in_arrow_function && has_return_type {
// However, if the arrow function we were able to parse is followed by another colon
// as in:
// a ? (x): string => x : null
Expand Down
3 changes: 1 addition & 2 deletions crates/oxc_parser/src/js/function.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -117,8 +117,7 @@ impl<'a> ParserImpl<'a> {
self.ctx = self.ctx.and_in(true).and_await(r#async).and_yield(generator);
let type_parameters = self.parse_ts_type_parameters();
let (this_param, params) = self.parse_formal_parameters(func_kind, param_kind);
let return_type =
self.parse_ts_return_type_annotation(Kind::Colon, /* is_type */ true);
let return_type = if self.is_ts { self.parse_ts_return_type_annotation() } else { None };
let body = if self.at(Kind::LCurly) { Some(self.parse_function_body()) } else { None };
self.ctx =
self.ctx.and_in(ctx.has_in()).and_await(ctx.has_await()).and_yield(ctx.has_yield());
Expand Down
53 changes: 13 additions & 40 deletions crates/oxc_parser/src/ts/types.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -59,9 +59,7 @@ impl<'a> ParserImpl<'a> {
self.parse_formal_parameters(FunctionKind::Declaration, FormalParameterKind::Signature);
let return_type = {
let return_type_span = self.start_span();
let Some(return_type) = self.parse_return_type(Kind::Arrow, /* is_type */ false) else {
return self.unexpected();
};
let return_type = self.parse_return_type();
self.ast.ts_type_annotation(self.end_span(return_type_span), return_type)
};

Expand Down Expand Up @@ -1038,47 +1036,22 @@ impl<'a> ParserImpl<'a> {

pub(crate) fn parse_ts_return_type_annotation(
&mut self,
kind: Kind,
is_type: bool,
) -> Option<Box<'a, TSTypeAnnotation<'a>>> {
if !self.is_ts {
return None;
}
if !self.at(Kind::Colon) {
return None;
}
let span = self.start_span();
self.parse_return_type(kind, is_type)
.map(|return_type| self.ast.alloc_ts_type_annotation(self.end_span(span), return_type))
let return_type = self.parse_return_type();
Some(self.ast.alloc_ts_type_annotation(self.end_span(span), return_type))
}

fn parse_return_type(&mut self, return_kind: Kind, is_type: bool) -> Option<TSType<'a>> {
if self.should_parse_return_type(return_kind, is_type) {
return Some(self.context(
Context::empty(),
Context::DisallowConditionalTypes,
Self::parse_type_or_type_predicate,
));
}
None
}

fn should_parse_return_type(&mut self, return_kind: Kind, _is_type: bool) -> bool {
if return_kind == Kind::Arrow {
self.bump_any();
return true;
}
if self.eat(Kind::Colon) {
return true;
}
// TODO
// if (isType && token() === SyntaxKind.EqualsGreaterThanToken) {
// // This is easy to get backward, especially in type contexts, so parse the type anyway
// parseErrorAtCurrentToken(Diagnostics._0_expected, tokenToString(SyntaxKind.ColonToken));
// nextToken();
// return true;
// }
false
fn parse_return_type(&mut self) -> TSType<'a> {
self.bump_any();
self.context(
Context::empty(),
Context::DisallowConditionalTypes,
Self::parse_type_or_type_predicate,
)
}

fn parse_type_or_type_predicate(&mut self) -> TSType<'a> {
Expand Down Expand Up @@ -1134,7 +1107,7 @@ impl<'a> ParserImpl<'a> {
self.error(diagnostics::ts_constructor_this_parameter(this_param.span));
}
}
let return_type = self.parse_ts_return_type_annotation(Kind::Colon, false);
let return_type = self.parse_ts_return_type_annotation();
self.parse_type_member_semicolon();
match kind {
CallOrConstructorSignature::Call => self.ast.ts_signature_call_signature_declaration(
Expand Down Expand Up @@ -1163,7 +1136,7 @@ impl<'a> ParserImpl<'a> {
let (key, computed) = self.parse_property_name();
let (this_param, params) =
self.parse_formal_parameters(FunctionKind::Declaration, FormalParameterKind::Signature);
let return_type = self.parse_ts_return_type_annotation(Kind::Colon, false);
let return_type = self.parse_ts_return_type_annotation();
self.parse_type_member_semicolon();
if kind == TSMethodSignatureKind::Set {
if let Some(return_type) = return_type.as_ref() {
Expand Down Expand Up @@ -1197,7 +1170,7 @@ impl<'a> ParserImpl<'a> {
let type_parameters = self.parse_ts_type_parameters();
let (this_param, params) = self
.parse_formal_parameters(FunctionKind::Declaration, FormalParameterKind::Signature);
let return_type = self.parse_ts_return_type_annotation(Kind::Colon, true);
let return_type = self.parse_ts_return_type_annotation();
self.parse_type_member_semicolon();
self.ast.ts_signature_method_signature(
self.end_span(span),
Expand Down
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