[jbdoderlein]

This PR try to provide error for current interpreter and for the type checker to the use of void returning function where a value is expected, like variable initialization, keyword default field or string interpolation. This is exactly the error that happen in #2905 .

I tried to be exhaustive as possible on place where this could happen (one test for each in type checker), but maybe i forgot some case.

Interpreter

For the runtime, clear unexpected type is raised when a void would be used for initialization.
Example of current runtime behavior :

rascal>void f(int x){return;}
void (int): function(|prompt:///|(0,22,<1,0>,<1,22>))

rascal>a = f(5);
ok
rascal>a
|prompt:///|(0,1,<1,0>,<1,1>): Uninitialized variable: a
Advice: |https://www.rascal-mpl.org/docs/Rascal/Errors/CompileTimeErrors/UninitializedVariable|

rascal>int a = f(5);
ok
rascal>a
|prompt:///|(0,1,<1,0>,<1,1>): Uninitialized variable: a
Advice: |https://www.rascal-mpl.org/docs/Rascal/Errors/CompileTimeErrors/UninitializedVariable|

rascal>"<f(3)>"
java.lang.NullPointerException
(internal error)
        at $(|main:///_dollar_|)

java.lang.NullPointerException
        at org.rascalmpl.interpreter.StringTemplateConverter$Visitor$IndentingAppend.appendToString(StringTemplateConverter.java:128)
        at ....

New behavior :

rascal>void f(int x){return;}
void (int): function(|prompt:///|(0,22,<1,0>,<1,22>))

rascal>a = f(5);
|prompt:///|(4,5,<1,4>,<1,9>): Non-void type required
Advice: |https://www.rascal-mpl.org/docs/Rascal/Errors/CompileTimeErrors/NonVoidTypeRequired|

rascal>int a = f(5);
|prompt:///|(0,13,<1,0>,<1,13>): Expected int, but got void
Advice: |https://www.rascal-mpl.org/docs/Rascal/Errors/CompileTimeErrors/UnexpectedType|

rascal>"<f(3)>"
|prompt:///|(2,4,<1,2>,<1,6>): Non-void type required
Advice: |https://www.rascal-mpl.org/docs/Rascal/Errors/CompileTimeErrors/NonVoidTypeRequired|

Type checker

I added/changed some check for void to handle these case, especially the overloaded function case : if any overloaded function would return void, an error is reported.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

❌ Patch coverage is 71.42857% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 45%. Comparing base (2386b79) to head (2c7a255).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...calmpl/interpreter/result/ConstructorFunction.java	33%	2 Missing and 2 partials ⚠️
...ascalmpl/interpreter/result/ConstructorResult.java	0%	1 Missing and 1 partial ⚠️
...rc/org/rascalmpl/semantics/dynamic/Expression.java	0%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##              main   #2933   +/-   ##
=======================================
  Coverage       45%     45%           
+ Complexity    6814    6812    -2     
=======================================
  Files          844     844           
  Lines        68823   68846   +23     
  Branches     10038   10049   +11     
=======================================
+ Hits         31429   31442   +13     
  Misses       35003   35003           
- Partials      2391    2401   +10     

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