Ticket #349 (closed defect: fixed)

Opened 5 years ago

Last modified 5 years ago

Internal error for forward reference

Reported by: Charles Owned by:
Priority: major Milestone:
Component: Cobra Compiler Version: 0.9.6
Keywords: Cc:


The following code causes an internal error:

class A

    var _foo =

class B

    def bar as String is shared
        return ''

Note that the equivalent C# works fine:

class A {

	protected string _foo = B.Bar();

class B {

	public static string Bar() {
		return "";


Though C# has no "var" at the member var level, nor "from var" for declaring properties.

Change History

Changed 5 years ago by Charles

Note that the error happens during "bind interface" on A and then _foo which causes a "bind implementation" for "", but is "not ready" because B has not yet had a "bind interface". This directly happens due to BoxMember.isUsed being set, but I haven't checked if it would happen further in the execution if .isUsed didn't trigger it.

It's kind of surprising that we don't run into this more often.

Changed 5 years ago by Charles

Changed 5 years ago by Charles

  • version changed from 0.9.4 to 0.9.6

Changed 5 years ago by Charles

  • status changed from new to closed
  • resolution set to fixed

Fixed in changeset:3093

The line is still not accepted, but it is now caught as an error and the error message gives 3 possible changes:

error: Cannot compile initialization expression at this point. Add an
explicit type to the `var` ("as <type>") or move to a `cue init` or change
the expression.

Changed 5 years ago by Charles

In the description, I said "The equivalent C#" but in fact there is no equivalent C# because there is no var type inference at the class member level. The C# code explicitly types the _foo member. I should have said "The closest C#..."

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