Mix of variable assignment and declaration in initialization clause of 'for' statement can lead to CS1002 errors

[Hafthor]

Version Used: C# 13 / SDK 9.0.200

Steps to Reproduce:

1. New C# console app project
2. Program.cs for(int a=0,b,c;;);
3. Build yields "Program.cs(1,12): CS1002 : ; expected" along with other related errors. Did not appear as error by IDE (VS or Rider).

Diagnostic Id: CS1002 : ; expected

Expected Behavior: should be able to mix declarations and assignments in initialization clause in 'for' statement

Actual Behavior: compilation errors - seems like if you include any assignments, then only the last variable is allowed to be declaration only.

RoslynBug20250215.zip

[CyrusNajmabadi]

Fixed with #77184

[Hafthor]

Confirmed that this is fixed in VS 17.13.4. Thanks!