unnecessary semi insertion for typescript type cast

[e-cloud]

Example:
source:

class A {
    handleInputFocus(): void {
        (<HTMLInputElement>this._input.nativeElement).select()
    }
}

expected output:
the same as source.

actual output:

class A {
    handleInputFocus(): void {
        ;(<HTMLInputElement>this._input.nativeElement).select()
    }
}

a semicolon is inserted before the left parentheses, which should not be.

[lydell]

This is actually intended. As described in the options:

Semicolons - Print semicolons at the ends of statements.

Valid options:

• true - add a semicolon at the end of every statement
• false - only add semicolons at the beginning of lines that may introduce ASI failures

See #1935 and the issues it links to.

[e-cloud]

I use tslint check the code for typescript files.

However, I notice that, after i use prettier to format ts files, all that warning tslint is complaining about are some code like:

{
     ;(<SomeType>varibale).somemethod()
     //...
}

Since the semi-inserted statement is the first statement within a code block, there is no way it would raise ASI failures. Am i right?

[lydell]

#736 (comment)