looks like leading comments wrong when var decls not ends with semi

[HairyRabbit]

Bug Report

Bugs maybe

Current Behavior
See the below astexplorer.net screenshots, the second var decl haven't leading comments:

If the first decl ends by semi, it works fine

Input Code

• REPL or Repo link if applicable:

I write a plugin to transform my code, it works with the leading comments

var s = `
/**
 * @test
 */
const a = {
  b: 42
}

/**
 * @test
 */
const c = 42
`
require('@babel/core').transform(s, { plugins: [
  function plugin(path) {
    return {
      visitor: {
        VariableDeclaration(path) { console.log(path.node.leadingComments, path.toString()) }
      }
    }
  }
]})

output:

Environment

[babel-bot]

Hey @HairyRabbit! We really appreciate you taking the time to report an issue. The collaborators
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so it's possible this won't be addressed swiftly.

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[coreyfarrell]

I've encountered this as well as it effects nyc ignore hints. From what I can tell the issue occurs to any comment following an object-literal assignment with no trailing semi-colon. I can only reproduce the error if the object-literal has at least one key.

obj = {a: 1}
/* istanbul ignore else */
if (true) {}

Using const, var or let to declare instead of assign obj makes no difference. The comment is recorded under tailingComments for the ObjectProperty representing the a property as well as the ExpressionStatement or VariableDeclaration, it is not recorded under leadingComments for the IfStatement.

Adding the semi-colon after {a: 1} fixes this. The comment is no longer recorded under tailingComments for the ObjectProperty, it is still recorded for the ExpressionStatement or VariableDeclaration and it is recorded under leadingComments of the IfStatement.

[nicolo-ribaudo]

Might be fixed by #10445

[coreyfarrell]

@nicolo-ribaudo I can confirm this fixes the issue both for my example code and for the code posted by @HairyRabbit.