Constructors: let me access instance fields in initializer expressions if they have been set in an initializing formal

[kevmoo]

This is okay

QrCode(int typeNumber, this.errorCorrectLevel)
  : this.typeNumber = typeNumber,
    moduleCount = typeNumber * 4 + 17 { ...

This is currently an error, but it'd be great if it worked.

QrCode(this.typeNumber, this.errorCorrectLevel)
  : moduleCount = typeNumber * 4 + 17 { ...

A nit, but nice to have.

[DartBot]

This comment was originally written by ladicek@gmail.com

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Can someone even count how many bugs asking for this has already been opened and then closed as WontFix?

[kevmoo]

...and my bad for not searching for existing bugs on this issue.

My apologies...for the dupe, not for wanting this :-)

[DartBot]

This comment was originally written by ladicek@gmail.com

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I'd love to have this too. I wouldn't worry about dupes (at least in this case), it's a clear sign that a lot of people want this.

Gilad says: if the sugar doesn't do what you want, don't use the sugar. Well... we want more sugar :-)

Specifically (pun intended), I'd love to have the word "not" deleted from this sentence "Using an initializing formal this.id in a formal parameter list does not introduce a formal parameter name into the scope of the constructor." in the chapter 7.5.1 of the spec.

[dgrove]

Set owner to @gbracha.
Removed Type-Defect label.
Added Type-Enhancement, Area-Language, Triaged labels.

[gbracha]

Here are some things I wish people would understand:

1. Features are not free. Every addition costs something, both in terms of its own design and implementation, and, often more significantly, in terms of opportunity cost. The time we spend on issues like this comes at the direct expense of addressing more significant problems.

2. Syntactic sugar is not a net win. The history of programming languages has shown this time and again.

3. It is just common courtesy to check if a feature request already exists. But no worries, I found one of the related bugs to list as as duplicate.

4. Being popular is nice, but that doesn't make it good (case in point: Javascript). In particular, the fact that a feature request is popular does not mean it's the right thing to do. I'm sorry, but this is a case in point. As I've explained repeatedly, the initial sugar had a great power-to-weight ratio: it's very simple, and it handles a very common situation. Leave it at that.

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   Added Duplicate label.
   Marked as being merged into Shorthand constructor this.x parameters prohibit access to x in initializer list #1970.