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Fix parsing type casted generic flow arrow exprs (#11955)
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@existentialism
existentialism committed Aug 19, 2020
1 parent 180e9c0 commit 96cc829
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Showing 10 changed files with 282 additions and 9 deletions.
51 changes: 42 additions & 9 deletions packages/babel-parser/src/plugins/flow.js
View file
Expand Up @@ -2674,28 +2674,57 @@ export default (superClass: Class<Parser>): Class<Parser> =>

let typeParameters;

const arrow = this.tryParse(() => {
const arrow = this.tryParse(abort => {
typeParameters = this.flowParseTypeParameterDeclaration();

const arrowExpression = this.forwardNoArrowParamsConversionAt(
typeParameters,
() =>
super.parseMaybeAssign(
() => {
const result = super.parseMaybeAssign(
refExpressionErrors,
afterLeftParse,
refNeedsArrowPos,
),
);

this.resetStartLocationFromNode(result, typeParameters);

return result;
},
);
arrowExpression.typeParameters = typeParameters;
this.resetStartLocationFromNode(arrowExpression, typeParameters);

// <T>(() => {}: any);
if (
arrowExpression.type !== "ArrowFunctionExpression" &&
arrowExpression.extra?.parenthesized
) {
abort();
}

// The above can return a TypeCastExpression when the arrow
// expression is not wrapped in parens. See also `this.parseParenItem`.
const expr = this.maybeUnwrapTypeCastExpression(arrowExpression);
expr.typeParameters = typeParameters;
this.resetStartLocationFromNode(expr, typeParameters);

return arrowExpression;
}, state);

const arrowExpression: ?N.ArrowFunctionExpression =
arrow.node?.type === "ArrowFunctionExpression" ? arrow.node : null;
let arrowExpression: ?(
| N.ArrowFunctionExpression
| N.TypeCastExpression
) = null;

if (!arrow.error && arrowExpression) return arrowExpression;
if (
arrow.node &&
this.maybeUnwrapTypeCastExpression(arrow.node).type ===
"ArrowFunctionExpression"
) {
if (!arrow.error && !arrow.aborted) {
return arrow.node;
}

arrowExpression = arrow.node;
}

// If we are here, both JSX and Flow parsing attempts failed.
// Give the precedence to the JSX error, except if JSX had an
Expand Down Expand Up @@ -3482,4 +3511,8 @@ export default (superClass: Class<Parser>): Class<Parser> =>
}
return false;
}
maybeUnwrapTypeCastExpression(node: N.Node) {
return node.type === "TypeCastExpression" ? node.expression : node;
}
};
1 change: 1 addition & 0 deletions ...bel-parser/test/fixtures/flow/typecasts/generic-arrow-func-invalid-parenthesized/input.js
View file
@@ -0,0 +1 @@
<T>(() => {}: any);
6 changes: 6 additions & 0 deletions ...parser/test/fixtures/flow/typecasts/generic-arrow-func-invalid-parenthesized/options.json
View file
@@ -0,0 +1,6 @@
{
"sourceType": "module",
"plugins": ["flow"],
"createParenthesizedExpressions": true,
"throws": "Expected an arrow function after this type parameter declaration (1:0)"
}
1 change: 1 addition & 0 deletions packages/babel-parser/test/fixtures/flow/typecasts/generic-arrow-func-invalid/input.js
View file
@@ -0,0 +1 @@
<T>(() => {}: any);
5 changes: 5 additions & 0 deletions packages/babel-parser/test/fixtures/flow/typecasts/generic-arrow-func-invalid/options.json
View file
@@ -0,0 +1,5 @@
{
"sourceType": "module",
"plugins": ["flow"],
"throws": "Expected an arrow function after this type parameter declaration (1:0)"
}
2 changes: 2 additions & 0 deletions packages/babel-parser/test/fixtures/flow/typecasts/generic-arrow-func-parenthesized/input.js
View file
@@ -0,0 +1,2 @@
(<T>() => {}: any);
((<T>() => {}): any);
5 changes: 5 additions & 0 deletions ...s/babel-parser/test/fixtures/flow/typecasts/generic-arrow-func-parenthesized/options.json
View file
@@ -0,0 +1,5 @@
{
"sourceType": "module",
"plugins": ["flow"],
"createParenthesizedExpressions": true
}
109 changes: 109 additions & 0 deletions ...es/babel-parser/test/fixtures/flow/typecasts/generic-arrow-func-parenthesized/output.json
View file
@@ -0,0 +1,109 @@
{
"type": "File",
"start":0,"end":41,"loc":{"start":{"line":1,"column":0},"end":{"line":2,"column":21}},
"program": {
"type": "Program",
"start":0,"end":41,"loc":{"start":{"line":1,"column":0},"end":{"line":2,"column":21}},
"sourceType": "module",
"interpreter": null,
"body": [
{
"type": "ExpressionStatement",
"start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
"expression": {
"type": "ParenthesizedExpression",
"start":0,"end":18,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":18}},
"expression": {
"type": "TypeCastExpression",
"start":1,"end":17,"loc":{"start":{"line":1,"column":1},"end":{"line":1,"column":17}},
"expression": {
"type": "ArrowFunctionExpression",
"start":1,"end":12,"loc":{"start":{"line":1,"column":1},"end":{"line":1,"column":12}},
"id": null,
"generator": false,
"async": false,
"params": [],
"body": {
"type": "BlockStatement",
"start":10,"end":12,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":12}},
"body": [],
"directives": []
},
"typeParameters": {
"type": "TypeParameterDeclaration",
"start":1,"end":4,"loc":{"start":{"line":1,"column":1},"end":{"line":1,"column":4}},
"params": [
{
"type": "TypeParameter",
"start":2,"end":3,"loc":{"start":{"line":1,"column":2},"end":{"line":1,"column":3}},
"name": "T",
"variance": null
}
]
}
},
"typeAnnotation": {
"type": "TypeAnnotation",
"start":12,"end":17,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":17}},
"typeAnnotation": {
"type": "AnyTypeAnnotation",
"start":14,"end":17,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":17}}
}
}
}
}
},
{
"type": "ExpressionStatement",
"start":20,"end":41,"loc":{"start":{"line":2,"column":0},"end":{"line":2,"column":21}},
"expression": {
"type": "ParenthesizedExpression",
"start":20,"end":40,"loc":{"start":{"line":2,"column":0},"end":{"line":2,"column":20}},
"expression": {
"type": "TypeCastExpression",
"start":21,"end":39,"loc":{"start":{"line":2,"column":1},"end":{"line":2,"column":19}},
"expression": {
"type": "ParenthesizedExpression",
"start":21,"end":34,"loc":{"start":{"line":2,"column":1},"end":{"line":2,"column":14}},
"expression": {
"type": "ArrowFunctionExpression",
"start":22,"end":33,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":13}},
"id": null,
"generator": false,
"async": false,
"params": [],
"body": {
"type": "BlockStatement",
"start":31,"end":33,"loc":{"start":{"line":2,"column":11},"end":{"line":2,"column":13}},
"body": [],
"directives": []
},
"typeParameters": {
"type": "TypeParameterDeclaration",
"start":22,"end":25,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":5}},
"params": [
{
"type": "TypeParameter",
"start":23,"end":24,"loc":{"start":{"line":2,"column":3},"end":{"line":2,"column":4}},
"name": "T",
"variance": null
}
]
}
}
},
"typeAnnotation": {
"type": "TypeAnnotation",
"start":34,"end":39,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":19}},
"typeAnnotation": {
"type": "AnyTypeAnnotation",
"start":36,"end":39,"loc":{"start":{"line":2,"column":16},"end":{"line":2,"column":19}}
}
}
}
}
}
],
"directives": []
}
}
2 changes: 2 additions & 0 deletions packages/babel-parser/test/fixtures/flow/typecasts/generic-arrow-func/input.js
View file
@@ -0,0 +1,2 @@
(<T>() => {}: any);
((<T>() => {}): any);
109 changes: 109 additions & 0 deletions packages/babel-parser/test/fixtures/flow/typecasts/generic-arrow-func/output.json
View file
@@ -0,0 +1,109 @@
{
"type": "File",
"start":0,"end":41,"loc":{"start":{"line":1,"column":0},"end":{"line":2,"column":21}},
"program": {
"type": "Program",
"start":0,"end":41,"loc":{"start":{"line":1,"column":0},"end":{"line":2,"column":21}},
"sourceType": "module",
"interpreter": null,
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{
"type": "ExpressionStatement",
"start":0,"end":19,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":19}},
"expression": {
"type": "TypeCastExpression",
"start":1,"end":17,"loc":{"start":{"line":1,"column":1},"end":{"line":1,"column":17}},
"expression": {
"type": "ArrowFunctionExpression",
"start":1,"end":12,"loc":{"start":{"line":1,"column":1},"end":{"line":1,"column":12}},
"id": null,
"generator": false,
"async": false,
"params": [],
"body": {
"type": "BlockStatement",
"start":10,"end":12,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":12}},
"body": [],
"directives": []
},
"typeParameters": {
"type": "TypeParameterDeclaration",
"start":1,"end":4,"loc":{"start":{"line":1,"column":1},"end":{"line":1,"column":4}},
"params": [
{
"type": "TypeParameter",
"start":2,"end":3,"loc":{"start":{"line":1,"column":2},"end":{"line":1,"column":3}},
"name": "T",
"variance": null
}
]
}
},
"typeAnnotation": {
"type": "TypeAnnotation",
"start":12,"end":17,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":17}},
"typeAnnotation": {
"type": "AnyTypeAnnotation",
"start":14,"end":17,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":17}}
}
},
"extra": {
"parenthesized": true,
"parenStart": 0
}
}
},
{
"type": "ExpressionStatement",
"start":20,"end":41,"loc":{"start":{"line":2,"column":0},"end":{"line":2,"column":21}},
"expression": {
"type": "TypeCastExpression",
"start":21,"end":39,"loc":{"start":{"line":2,"column":1},"end":{"line":2,"column":19}},
"expression": {
"type": "ArrowFunctionExpression",
"start":22,"end":33,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":13}},
"id": null,
"generator": false,
"async": false,
"params": [],
"body": {
"type": "BlockStatement",
"start":31,"end":33,"loc":{"start":{"line":2,"column":11},"end":{"line":2,"column":13}},
"body": [],
"directives": []
},
"typeParameters": {
"type": "TypeParameterDeclaration",
"start":22,"end":25,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":5}},
"params": [
{
"type": "TypeParameter",
"start":23,"end":24,"loc":{"start":{"line":2,"column":3},"end":{"line":2,"column":4}},
"name": "T",
"variance": null
}
]
},
"extra": {
"parenthesized": true,
"parenStart": 21
}
},
"typeAnnotation": {
"type": "TypeAnnotation",
"start":34,"end":39,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":19}},
"typeAnnotation": {
"type": "AnyTypeAnnotation",
"start":36,"end":39,"loc":{"start":{"line":2,"column":16},"end":{"line":2,"column":19}}
}
},
"extra": {
"parenthesized": true,
"parenStart": 20
}
}
}
],
"directives": []
}
}

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