Anonymous functions - Errors with scoped variables - (local and global variables).
Edit:
I tried it intensively, also with some modifications. Seems to be completely solved. Thank you!!
=========================================================================================
Edit:
I updated to:
```
Verbose: Free Pascal Compiler version 3.3.1-12784-gb9aeeaa6e3 [2023/06/21] for x86_64
```
The problems vanish with ``{$mode delphi}``, but persist with ``{$mode objfpc}``.
This Issue replaces #40315. I describe the remaining problems in better detail here.
So #40315 is closed now.
I get various errors with the same source. The errors change when I change variable declarations.
_All these declarations, which do not compile, are syntactic correct_.
**Example:**
The following source is _exactly_ equal, only difference: I removed the (unused) local variable "str".
This results in compile error:
```
project2.lpr(41,25) Error: Overloaded identifier "__FPCINTERNAL__ANONYMOUS_2" isn't a function
```
```pascal
program project2;
// This program compiles and runs in Delphi and in FPC. (at least should run in FPC)
// It is intentionally designed this way.
{$ifdef FPC}
{$mode objfpc}{$H+}
{$modeswitch functionreferences}
{$modeswitch anonymousfunctions}
// {$warn 5036 off}// "Warning: (5036) Local variable "$Capturer" does not seem to be initialized"
{$endif}
// uses
{$IFDEF UNIX}
cthreads,
{$ENDIF}
// Classes, Sysutils { you can add units after this };
type
T_X = String; // Type of Test-variable X
TfuncS = reference to function: T_X;
TfuncF = reference to function(s: T_X): TfuncS;
var f_inner: TfuncS;
f_outer: TfuncF;
//------------------------------------------------------------------------------
procedure caller;
begin
f_inner();
end;
//------------------------------------------------------------------------------
procedure main;
var X: T_X;
// str:String;
f_outer: TfuncF;
begin
X := '1234';
f_outer := function(s: T_X): TfuncS // This captures local and persistent copy of "X"
begin
Result := function: T_X
begin
Writeln(s);
Result := s;
end;
Writeln('Outer function was called');
end;
f_inner := f_outer(X); // This instantiates the outer function and f_inner and captures their local context.
X := '0'; // Erase the T_X content
Writeln('now calling f_inner');
caller(); // This line prints the T_X s=1234, which was captured by the outer function.
// f_inner will be called from an external context, this is just for test and demonstration
end;
//------------------------------------------------------------------------------
begin
main;
Writeln('Now the context of "main()" is lost. Can we still print the variable "X"?');
if f_inner() = '1234' then
Writeln('Yes! :-)')
else
Writeln('No! :-(');
readln;
end.
```
**New Example:**
This source is equal again, I removed only the local variable "f_outer" and it should now use the global variable with same name instead.
This gives the same compile error.
Strangely, if I then also remove the _unused_ local variable "str", it compiles and runs.
```pascal
program project2;
// This program compiles and runs in Delphi and in FPC. (at least should run in FPC)
// It is intentionally designed this way.
{$ifdef FPC}
{$mode objfpc}{$H+}
{$modeswitch functionreferences}
{$modeswitch anonymousfunctions}
// {$warn 5036 off}// "Warning: (5036) Local variable "$Capturer" does not seem to be initialized"
{$endif}
// uses
{$IFDEF UNIX}
cthreads,
{$ENDIF}
// Classes, Sysutils { you can add units after this };
type
T_X = String; // Type of Test-variable X
TfuncS = reference to function: T_X;
TfuncF = reference to function(s: T_X): TfuncS;
var f_inner: TfuncS;
f_outer: TfuncF;
//------------------------------------------------------------------------------
procedure caller;
begin
f_inner();
end;
//------------------------------------------------------------------------------
procedure main;
var X: T_X;
str:String;
// f_outer: TfuncF;
begin
X := '1234';
f_outer := function(s: T_X): TfuncS // This captures local and persistent copy of "X"
begin
Result := function: T_X
begin
Writeln(s);
Result := s;
end;
Writeln('Outer function was called');
end;
f_inner := f_outer(X); // This instantiates the outer function and f_inner and captures their local context.
X := '0'; // Erase the T_X content
Writeln('now calling f_inner');
caller(); // This line prints the T_X s=1234, which was captured by the outer function.
// f_inner will be called from an external context, this is just for test and demonstration
end;
//------------------------------------------------------------------------------
begin
main;
Writeln('Now the context of "main()" is lost. Can we still print the variable "X"?');
if f_inner() = '1234' then
Writeln('Yes! :-)')
else
Writeln('No! :-(');
readln;
end.
```
issue