William C. Johnson

[compiler] `IfExpression`s and `AssignmentExpression`s in loop bodies

1

## Problem `[email protected]`: [Lscdiag](https://wcjohnson.github.io/lscdiag/?v=1&s=eMOafVDDkU7DgzAMw7wVK0_CoMKVKV0pwrAOUMK_woAfYBMKwqnDm8KFwqVpSRzChMKow7rDrzjCg8KHPsONL8OnO8KfwqzCsyfDkcKab8KKHsKDwqgmw7HDlsKrMWFdw7dIwqpRwqQSw5Mfw7c_ZcOuw7JOchXDpsKuw5zDksODw6ZTwocoKsOyEcOnw6zCkmMSYcKIXmPDqmzDkMKiEsOtw5U1w5w8w68dQDt4wrBIYMOgCcOkwo7DoRHDssKEwqtVwpXDhgBfw4rDssOIwrTCoMKPwqhPw7_DolnDnsKwXizDuV_CjzbDoMOSVsKww612w4nDt05ww55oUhxSw698w7XCq8OMw6QhEwEtasOCw6ZlaDjCq8KLw5bCpsK7BsOXwprDrsO8woPCoR_CjUXDj8O5wq3DqcKOFMK0NyPDlXJdwq7Ct2LCnsOZa00gw552w6EXwod5w74FwqnDhW3Dsg#) ```js f() -> for let i = 0; i < 10; i++: val = if check: val2 = 3 val2 else: val3 = 4 val3 ```...

[compiler] Conditional expressions probably need to return `undefined` by default

1

## Problem ```js x = if false: 1 // x === null y = (-> if false: 1 )() // y === undefined ``` Wrapping an expression in a function...

[compiler] `IfExpression`s generating undefined instead of null

2

## Problem `[email protected]`: ```js x = if a: if b: c ``` ```js const x = a ? b ? c : void 0 : null; ``` If `a` is...

[parser] ASI for export specifiers

1

`[email protected]`: ```js export { a b } ``` ```js Unexpected token, expected , (3:2) ``` The same ASI (ACI?) rules should probably apply here as with objects/arrays.

[parser] Improper coercion to lvalue in ConditionalExpressions (possibly elsewhere?)

1

`[email protected]`: https://wcjohnson.github.io/lscdiag/?v=1&s=eMOafcKOQQrCgzAQRcKvIsKzwqogEsKpFsOqwqbCnsKgF1ApMcKJNjbCmsKQTMKgIMK5e8KTHsOAw5nDjHzDuMK8eQfDjMOywovDngoHw60Bwq_CjcKawrTCu24TSDlFwpoSW2vCvsKuw457EsOnw7rCucOVwobCr8KNIsKaQMKLw5bCi1DCnDUOcMOaWybDksKlHMKDFsOowqXCn8OGfMOYacO2w4jCpkvDj8OGPGszPsOsEEFewqYew5Ipw6rDtMKkwqjDhgLCnFDCgsKhw6BPw40jwqTCqsOSO8K9w49yw7nCq8Opw41IJWzDhCrCucK8w5ExKw12wqRsw4o7woQQwrtKOsKMwqwTw4UxwoQfwpw7VHQ The highlighted AST node is being parsed as an `ArrayPattern` when it should be an `ArrayExpression`. Note that this does not happen above in the `CallExpression` but only...

[parser] Flow types and syntax errors in function bodies

1

`[email protected]`: ```js a(b?: T1): T2 -> switch ``` ```js unknown: Unexpected token (1:4) > 1 | a(b?: T1): T2 -> | ^ 2 | switch 3 | ``` The parser...

[compiler] Flow type annotations triggering stdlib imports.

3

On `[email protected]`: ```js import type Foo from 'foo'; import type Foo2 from 'foo'; import type Foo3 from 'foo'; var a: {add(x:Foo, ...y:Array): Foo3}; a; ``` ```js import add from 'lodash/add';...

[plugin] Assignment expressions and implicit returns

3

## Problem ```js f() -> { destructure } = invalid ``` ``` unknown: Property argument of ReturnStatement expected node to be of a type ["Expression"] but instead got "ObjectPattern" ```...

[plugin] improve generated Comprehension code

1

With #4 just about done and dusted, this is my next subject of interest. Laying out some thoughts: ## Unrolling We talked about possibly pulling the comprehensions out of immediate...

[plugin] producing nodes without source locations

2

Many AST nodes are being generated without source locations, which breaks various tools in the ecosystem, including anything that uses source maps.