CODEWITHSUNDEEP
c#
Buildstarted
Buildstarted

Reputation: 26689

Mutally exclusive constraints on two methods with the same signature

So these two methods have the same signature but different constraints

public static void Method<T>(ref T variable) where T : struct { }

public static void Method<T>(ref T variable) where T : class { }

But they cannot be defined in a single class because they have the same signatures. But in this particular case they're mutually exclusive. (Unless I'm wrong about that)

I understand you can put additional constraints besides class and struct but you can't specify both struct and class on the same method. So why would this fail to compile?

Upvotes: 9

Views: 661

Answers (3)

bluevector
bluevector

Reputation: 3493

They are semantically mutually exclusive, yes. But the compiler sees them as having the same "name", hence the ambiguity. "Name" here meaning "method signature".

Upvotes: 4

earlNameless
earlNameless

Reputation: 2918

Although the compiler could be smart enough to figure it out (which it appears not to be), you do not know what to do for object (as it can be class or struct).

Upvotes: 4

Oded
Oded

Reputation: 498972

The generic constraints are not considered part of the method signature (thanks @Anthony for the link).

As far as the compiler is concerned you have a duplicate method - same numbers and types of parameters.

Upvotes: 10

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