Omsmith/destructured assignments #741
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| if( semanticModel.GetTypeInfo( assignmentSyntax.Right ).Type is INamedTypeSymbol assignedType | ||
| && assignedType.IsTupleType | ||
| ) { |
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Handle Value Tuples.
GetDeconstructionInfo does return stuff for them, but they don't have a Method, just some nested deconstructioninfos with Identity conversions - so need to extract the type info separately anyway.
| return AssignmentInfo.Create( | ||
| isInitializer: false, | ||
| expression: assignmentSyntax.Right, | ||
| assignedType: null |
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assignedType: null
This is an "error / unknown assignment" - there's probably a better way to signal this...
| DeconstructionInfo deconstruction = semanticModel.GetDeconstructionInfo( assignmentSyntax ); | ||
| if( deconstruction.Method == null ) { | ||
| return AssignmentInfo.Create( | ||
| isInitializer: false, | ||
| expression: assignmentSyntax.Right, | ||
| assignedType: null | ||
| ); | ||
| } | ||
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||
| if( deconstruction.Method.Parameters.Length != lhsExpressions.Length ) { | ||
| return AssignmentInfo.Create( | ||
| isInitializer: false, | ||
| expression: assignmentSyntax.Right, | ||
| assignedType: null | ||
| ); | ||
| } | ||
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| return AssignmentInfo.Create( | ||
| isInitializer: false, | ||
| expression: assignmentSyntax.Right, | ||
| assignedType: deconstruction.Method.Parameters[ i ].Type | ||
| ); |
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Only handles simple deconstructions, not nested ones like so:
class A {
public void Deconstruct( out string X, out B foo );
}
class B {
public void Deconstruct( out string Y, out string Z );
}
public void Foo() {
var (x, y, z) = new A();
}
| ); | ||
| } | ||
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||
| if( deconstruction.Method.Parameters.Length != lhsExpressions.Length ) { |
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Don't believe this can happen, just a sanity check.
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Actually I lied there, this is what's filtering out nested deconstruction.
I don't think it would be terribly hard to support, I just don't care to write the code.
| diagnostic = Diagnostic.Create( | ||
| Diagnostics.NonImmutableTypeHeldByImmutable, | ||
| assignment.Expression.GetLocation(), | ||
| "blarg", "blarg", "blarg" | ||
| ); | ||
| return AssignmentQueryKind.Hopeless; |
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Need to add some sort of new "Unexpected" diagnostic. (We currently have UnexpectedTypeKind and UnexpectedMemberKind)
| @@ -333,6 +333,18 @@ ExpressionSyntax expression | |||
| assignedType: assignedType | |||
| ); | |||
| } | |||
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| public static AssignmentInfo Create( | |||
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Could the constructor just be public?
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Yeah for sho. Discovering the end solution organically.
WIP - opening up to chat