Null coalescing assignment for nullable value type should set state of nullable type not underlying type #67468
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…f nullable type not underlying type
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jjonescz
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Mar 24, 2023
src/Compilers/CSharp/Test/Semantic/Semantics/NullableReferenceTypesTests.cs
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Co-authored-by: Jan Jones <[email protected]>
RikkiGibson
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Apr 7, 2023
| Debug.Assert(actualType is { }); | ||
| Debug.Assert(actualType.ContainsErrorType() || | ||
| targetType.ContainsErrorType() || | ||
| isOfTypeOrBaseOrInterface(actualType, targetType)); |
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Should we use some "classify conversion" API instead? e.g. if it's identity or implicit reference conversion, maybe that's good enough? #Resolved
| @@ -5105,12 +5149,26 @@ private static BoundExpression SkipReferenceConversions(BoundExpression possibly | |||
| var leftState = this.State.Clone(); | |||
| LearnFromNonNullTest(leftOperand, ref leftState); | |||
| LearnFromNullTest(leftOperand, ref this.State); | |||
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| // If we are assigning the underlying value type to a nullable value type variable, | |||
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I found this comment a little unclear. I think it should say that we do a special step to set the nullable variable's top level state within this block, then change the slot to later simulate an assignment from the RHS to the LHS's Value property, to update nullable states within the underlying value type. #Resolved
RikkiGibson
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Apr 17, 2023
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For a null coalescing assignment of a nullable value type, where the RHS is an instance of the underlying type, the nullable state of the LHS should be assigned a (non-null) nullable value type that wraps the state of the underlying value type from the RHS. Previously, the state of the LHS was set to the state from the RHS directly.
Fixes #67040