[Oberon] Dynamic type of record var parameter

[August Karlstrom]

On 2021-01-11 23:44, chris wrote:
> What  surprises me is the last one. The dynamic type is r2 not r0. It
> looks like the compiler uses the static type from the local variable p
> instead of the dynamic type of p^. Is this intended behavior?

Probably an error in the Project Oberon compiler. I just tried your 
example with OBNC (replacing Texts with Out) and it (correctly?) prints

	is r2
	is r0
	is r2
	is r2

Here is a somewhat minimal example which highlights the issue:

	MODULE Test2;
	
		IMPORT Out;
	
		TYPE
			T0 = RECORD END;
			T1 = RECORD (T0) END;
			P0 = POINTER TO T0;
			P1 = POINTER TO T1;

		PROCEDURE PrintDynamicType(VAR x: T0);
		BEGIN
			CASE x OF
				T1: Out.String("T1") |
				T0: Out.String("T0")
			END;
			Out.Ln
		END PrintDynamicType;
	
		PROCEDURE Run*;
			VAR p0: P0;
				p1: P1;
		BEGIN
			NEW(p1);
			p0 := p1;
			PrintDynamicType(p0^)
		END Run;

	END Test2.


-- August