Support widgets and placeholders in more complex expressions

[Frizi]

Pull Request Description

Implements #5032

Added support for widgets in infix expressions (right now only used for file paths)

Widgets and placeholders are handled for all chained methods within a node

The qualified method call convention and static methods no longer confuse the argument placeholders

Type constructor expressions now receive placeholder arguments. The placeholders work on nested expressions within a node.

Checklist

Please include the following checklist in your PR:

• The documentation has been updated if necessary.
• All code conforms to the
  Scala,
  Java,
  and
  Rust
  style guides.
• All code has been tested:
  • Unit tests have been written where possible.
  • If GUI codebase was changed: Enso GUI was tested when built using BOTH
    ./run ide build and ./run ide watch.

[farmaazon]

1. Perhaps the engine problem: on screenshot below, I had the node on the right first, and then just added the node on the left; as you see, the drop down does not suggest column names anymore
   

2. On the same picture you can see that if I pick some Filter_Condition (on the screenshot Equal) then I cannot change it anymore. Not sure if part of this task though.

3. Also not sure if part of this task, but if I write Equal by hand (or remove _ placeholder), then I don't see drop downs anymore. Visualization also show nothing.

Continuing QA...

[farmaazon]

No other issues found.

[Frizi]

@farmaazon

1. Yes, this looks to be an engine problem. What you see is that the node on the left started using tag_values (static dropdown data), which means the widget query didn't return a widget. I suspect that happens when that node's expression postion in the source file is below an expression that caused an evaluation exception. In this case, I believe that the filter condition expression causes it. Which engine version are you using?

Also, the trailing _ in the Filter_Condition suggestions has been removed in this PR. You need to build the standard library locally to see that. This is the only non-IDE change.

2. This looks wrong, and looks to be my fault. I'm going to investigate it further. Looks like expression groups don't create the right span tree.

3. is essentially a combination of 1. and 2. You don't get the widgets and visualization because there is an error in the graph, and because there is something wrong with handling Group nodes in argument position. Other than that, the inserted to placeholder looks right.

[farmaazon]

@farmaazon

1. Yes, this looks to be an engine problem. What you see is that the node on the left started using tag_values (static dropdown data), which means the widget query didn't return a widget. I suspect that happens when that node's expression postion in the source file is below an expression that caused an evaluation exception. In this case, I believe that the filter condition expression causes it. Which engine version are you using?

I use nightly from 2023-02-15

2. This looks wrong, and looks to be my fault. I'm going to investigate it further. Looks like expression groups don't create the right span tree.

I can confirm this fixed. As other bugs are related to the Engine, the QA is green.