Bug 39370 - CS1061 - Generic function constraint that inherits from another constraint: the latter won't propagate
Summary: CS1061 - Generic function constraint that inherits from another constraint: t...
Alias: None
Product: Compilers
Classification: Mono
Component: C# ()
Version: unspecified
Hardware: PC Windows
: --- normal
Target Milestone: ---
Assignee: Marek Safar
Depends on:
Reported: 2016-03-04 17:12 UTC by athibodeau
Modified: 2016-03-05 13:58 UTC (History)
1 user (show)

Is this bug a regression?: ---
Last known good build:

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Description athibodeau 2016-03-04 17:12:41 UTC
When a generic function constraint inherits from another constraint, the latter is not propagated when compiling and we get a CS1061 error. I have tested with Mono (mcs --version says "Mono C# compiler version").

The following example compiles successfully with Visual Studio 2013 (target framework: tested with .NET Framework 4.5 and 2.0), but doesn't compile with Mono.

public class A
	public void F()

public class B : A

public class C : B

class Tester
	public void Test()
		GenericF<B, C>(new C());

	private void GenericF<T1, T2>(T2 t2)
		where T1 : B
		where T2 : T1
		t2.F(); // T2 is T1, T1 is B, so T2 is be B and contains F(). CS1061
Comment 1 Marek Safar 2016-03-05 13:58:43 UTC
Already fixed in master and Mono 4.4