Emit issue with member access dot operator and parentheses usually in conjunction with type assertion

[gdelmas]

Code

a.foo()
(b).foo()

Expected emit:

a.foo();
(b).foo();

Actual emit:

a.foo()(b).foo();

This becomes an issue when using type assertions inline:

Code

a.foo()
(b as Bar).foo()

Expected emit:

a.foo();
b.foo();

Actual emit:

a.foo()(b).foo();

---

Angle brackets type assertion have a similar issue:

Code

a.foo()
<Bar>b.foo()

Actual emit:

a.foo()
    < Bar > b.foo();

[mhegazy]

Unfortunately these are the JavaScript Automatic SemiColon Insertion rules.

TypeScript is a super-set of JavaScript, and the samples above are valid JS code samples, and they have valid semantics. the emitted code has to match these semantics.

[gdelmas]

thanks for your reply @mhegazy. i thought that it is a tricky case, as sometimes a multiline expression might be intended.

i might create a tslint warning to detect it in conjunction with assertions. or might this be a case where tsc can warn itself?

[RyanCavanaugh]

I believe there's already a TSLint rule for missing semicolons

[gdelmas]

do you mean this tslint core rule:

"semicolon": [true, "never"]

"never" disallows semicolons at the end of every statement except for when they are necessary.

the rule does not warn if a semicolon in conjunction with a type assertion might be required. it also fails in some other cases, and warns. for example:

super(); <-- rule thinks this is unnecessary
(a as Bar).foo()

[RyanCavanaugh]

Sorry, I totally misread that. Disregard.

@mhegazy perhaps we should disallow boolean as an operand to > / <, even if the other operand is any ?

[ajafff]

@gdelmas you can use the no-unexpected-multiline provided by tslint-eslint-rules

[mhegazy]

@mhegazy perhaps we should disallow boolean as an operand to > / <, even if the other operand is any

👍

[mhegazy]

Filed #15506 to track it.

[mhegazy]

Automatically closing this issue for housekeeping purposes. The issue labels indicate that it is unactionable at the moment or has already been addressed.