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Deconstruction is ambiguous

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6

0

I have a vector class with two deconstruction methods as follows:

public readonly struct Vector2

 public readonly double X, Y;

 ...

 public void Deconstruct( out double x, out double y )
 
 x = this.X;
 y = this.Y;
 

 public void Deconstruct( out Vector2 unitVector, out double length )
 
 length = this.Length;
 unitVector = this / length;
 

Somewhere else I have:

Vector2 foo = ...
(Vector2 dir, double len) = foo;

This gives me:

CS0121: The call is ambiguous between the following methods or properties: 'Vector2.Deconstruct(out double, out double)' and 'Vector2.Deconstruct(out Vector2, out double)'

How is this ambiguous?

Edit: Calling Deconstruct manually works fine:

foo.Deconstruct( out Vector2 dir, out double len );

c# c#-7.3

share|improve this question

edited 4 hours ago

Chris

asked 4 hours ago

ChrisChris

4,7381025

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  If your Vector class had implicit conversion to/from a double, say, then this would be ambiguous.
  
  – Ian Mercer
  4 hours ago
  

  
  
  
  

add a comment | 

6

0

I have a vector class with two deconstruction methods as follows:

public readonly struct Vector2

 public readonly double X, Y;

 ...

 public void Deconstruct( out double x, out double y )
 
 x = this.X;
 y = this.Y;
 

 public void Deconstruct( out Vector2 unitVector, out double length )
 
 length = this.Length;
 unitVector = this / length;
 

Somewhere else I have:

Vector2 foo = ...
(Vector2 dir, double len) = foo;

This gives me:

CS0121: The call is ambiguous between the following methods or properties: 'Vector2.Deconstruct(out double, out double)' and 'Vector2.Deconstruct(out Vector2, out double)'

How is this ambiguous?

Edit: Calling Deconstruct manually works fine:

foo.Deconstruct( out Vector2 dir, out double len );

c# c#-7.3

share|improve this question

edited 4 hours ago

Chris

asked 4 hours ago

ChrisChris

4,7381025

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  If your Vector class had implicit conversion to/from a double, say, then this would be ambiguous.
  
  – Ian Mercer
  4 hours ago
  

  
  
  
  

add a comment | 

I have a vector class with two deconstruction methods as follows:

public readonly struct Vector2

 public readonly double X, Y;

 ...

 public void Deconstruct( out double x, out double y )
 
 x = this.X;
 y = this.Y;
 

 public void Deconstruct( out Vector2 unitVector, out double length )
 
 length = this.Length;
 unitVector = this / length;
 

Somewhere else I have:

Vector2 foo = ...
(Vector2 dir, double len) = foo;

This gives me:

CS0121: The call is ambiguous between the following methods or properties: 'Vector2.Deconstruct(out double, out double)' and 'Vector2.Deconstruct(out Vector2, out double)'

How is this ambiguous?

Edit: Calling Deconstruct manually works fine:

foo.Deconstruct( out Vector2 dir, out double len );

c# c#-7.3

share|improve this question

edited 4 hours ago

Chris

asked 4 hours ago

ChrisChris

4,7381025

public readonly struct Vector2

 public readonly double X, Y;

 ...

 public void Deconstruct( out double x, out double y )
 
 x = this.X;
 y = this.Y;
 

 public void Deconstruct( out Vector2 unitVector, out double length )
 
 length = this.Length;
 unitVector = this / length;
 

Vector2 foo = ...
(Vector2 dir, double len) = foo;

CS0121: The call is ambiguous between the following methods or properties: 'Vector2.Deconstruct(out double, out double)' and 'Vector2.Deconstruct(out Vector2, out double)'

foo.Deconstruct( out Vector2 dir, out double len );

share|improve this question

edited 4 hours ago

Chris

asked 4 hours ago

ChrisChris

4,7381025

share|improve this question

edited 4 hours ago

Chris

asked 4 hours ago

ChrisChris

4,7381025

asked 4 hours ago

ChrisChris

4,7381025

asked 4 hours ago

ChrisChris

4,7381025

1 Answer
1

active

oldest

votes

7

This is by design in C#. Overloads of Deconstruct must have different arity (number of parameters), otherwise they are ambiguous.

Pattern-matching does not have a left-hand-side. More elaborate
pattern-matching scheme is to have a parenthesized list of patterns to
match, and we use the number of patterns to decide which Deconstruct
to use.
- Neal Gafter https://github.com/dotnet/csharplang/issues/1998#issuecomment-438472660

share|improve this answer

edited 4 hours ago

answered 4 hours ago

AsikAsik

14.4k349105

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  That is thoroughly disappointing!
  
  – Chris
  4 hours ago
  

  
  
  
  

add a comment | 

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7

This is by design in C#. Overloads of Deconstruct must have different arity (number of parameters), otherwise they are ambiguous.

Pattern-matching does not have a left-hand-side. More elaborate
pattern-matching scheme is to have a parenthesized list of patterns to
match, and we use the number of patterns to decide which Deconstruct
to use.
- Neal Gafter https://github.com/dotnet/csharplang/issues/1998#issuecomment-438472660

share|improve this answer

edited 4 hours ago

answered 4 hours ago

AsikAsik

14.4k349105

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  That is thoroughly disappointing!
  
  – Chris
  4 hours ago
  

  
  
  
  

add a comment | 

7

This is by design in C#. Overloads of Deconstruct must have different arity (number of parameters), otherwise they are ambiguous.

Pattern-matching does not have a left-hand-side. More elaborate
pattern-matching scheme is to have a parenthesized list of patterns to
match, and we use the number of patterns to decide which Deconstruct
to use.
- Neal Gafter https://github.com/dotnet/csharplang/issues/1998#issuecomment-438472660

share|improve this answer

edited 4 hours ago

answered 4 hours ago

AsikAsik

14.4k349105

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  That is thoroughly disappointing!
  
  – Chris
  4 hours ago
  

  
  
  
  

add a comment | 

This is by design in C#. Overloads of Deconstruct must have different arity (number of parameters), otherwise they are ambiguous.

Pattern-matching does not have a left-hand-side. More elaborate
pattern-matching scheme is to have a parenthesized list of patterns to
match, and we use the number of patterns to decide which Deconstruct
to use.
- Neal Gafter https://github.com/dotnet/csharplang/issues/1998#issuecomment-438472660

share|improve this answer

edited 4 hours ago

answered 4 hours ago

AsikAsik

14.4k349105

share|improve this answer

edited 4 hours ago

answered 4 hours ago

AsikAsik

14.4k349105

answered 4 hours ago

AsikAsik

14.4k349105

answered 4 hours ago

AsikAsik

14.4k349105