Anonymous functions: Fatal: Internal error 200109092 issued by compiler when setting result of an anonymous function to a procedure cast to a function reference
## Summary
When using an anonymous function that returns a function reference, the compile fails with `Fatal: Internal error 200109092` when the result variable is set to a function reference cast of an existing procedure with a matching function reference prototype.
## System Information
- **Operating system:** Linux, AlmaLinux 9.1, x86_64
- **Processor architecture:** x86-64
- **Compiler version:** 3.3.1-12460-g0e05e908d5
- **Device:** Computer
## Steps to reproduce
When trying to compile the following program:
```pascal
program something_cool;
{$Mode objfpc}{$H+}
{$ModeSwitch anonymousfunctions}
{$ModeSwitch functionreferences}
{$ModeSwitch nestedprocvars}
type
TVoidFunc = reference to procedure;
TFuncMaker = reference to function(const thing: string): TVoidFunc;
procedure something;
begin
writeln('something...');
end;
procedure main;
var
cool_bingo: TVoidFunc;
coolifier: TFuncMaker;
begin
coolifier := function (const thing: string): TVoidFunc
begin
// result := procedure begin writeln('cool ', thing) end;
result := TVoidFunc(@something);
end;
cool_bingo := coolifier('bingo');
cool_bingo();
end;
begin
main;
end.
```
The compile fails as follows:
```shell
$ fpc something_cool.pas
Free Pascal Compiler version 3.3.1 [2023/02/09] for x86_64
Copyright (c) 1993-2023 by Florian Klaempfl and others
Target OS: Linux for x86-64
Compiling something_cool.pas
something_cool.pas(25,14) Fatal: Internal error 200109092
Fatal: Compilation aborted
Error: /home/dev/fpc_usr/lib/fpc/3.3.1/ppcx64 returned an error exitcode
```
## Example Project
See Steps to Reproduce.
## What is the current bug behavior?
See Steps to Reproduce.
## What is the expected (correct) behavior?
That it compiles and runs, because this compiles and runs:
```pascal
program something_cool2;
{$Mode objfpc}{$H+}
{$ModeSwitch anonymousfunctions}
{$ModeSwitch functionreferences}
{$ModeSwitch nestedprocvars}
type
TVoidFunc = reference to procedure;
TFuncMaker = reference to procedure(const thing: string; var func: TVoidFunc);
function main: TVoidFunc;
var
cool_bingo: TVoidFunc;
coolifier: TFuncMaker;
n: integer = 0;
begin
coolifier := procedure (const thing: string; var func: TVoidFunc)
begin
func := procedure begin
inc(n);
writeln(n, ' cool ', thing);
end;
end;
coolifier('bingo', cool_bingo);
cool_bingo();
result := cool_bingo;
end;
var
func: TVoidFunc;
begin
func := main;
func();
end.
```
```shell
$ fpc something_cool2.pas
Free Pascal Compiler version 3.3.1 [2023/02/09] for x86_64
Copyright (c) 1993-2023 by Florian Klaempfl and others
Target OS: Linux for x86-64
Compiling something_cool2.pas
Linking something_cool2
35 lines compiled, 0.1 sec, 144624 bytes code, 58008 bytes data
$ ./something_cool2
1 cool bingo
2 cool bingo
```
## Relevant logs and/or screenshots
See Steps to Reproduce.
## Possible fixes
None that I know of.
## Related bugs
This is related to https://gitlab.com/freepascal.org/fpc/source/-/issues/40142, but with a different compiler error message.
https://gitlab.com/freepascal.org/fpc/source/-/issues/20251 has the same internal error, but does not appear to be related.
issue