Fix S3878 AD0001: Cover the case of ImplicitArrayCreationExpressionSyntax

[mary-georgiou-sonarsource]

No description provided.

[Tim-Pohlmann]

The switch can be simplified, looks good otherwise.

[Tim-Pohlmann]

Suggested change

	argument switch
	{
	_ when argument.Expression as ArrayCreationExpressionSyntax is { } arrayCreation => model.GetTypeInfo(arrayCreation.Type.ElementType).Type,
	_ when argument.Expression as ImplicitArrayCreationExpressionSyntax is { } implicitArrayCreation => model.GetTypeInfo(implicitArrayCreation).Type,
	_ => null
	};
	argument.Expression switch
	{
	ArrayCreationExpressionSyntax arrayCreation => model.GetTypeInfo(arrayCreation.Type.ElementType).Type,
	ImplicitArrayCreationExpressionSyntax implicitArrayCreation => model.GetTypeInfo(implicitArrayCreation).Type,
	_ => null
	};

[martin-strecker-sonarsource]

This looks wrong. It does return the array type (e.g., int[]), but the method is called ArrayElementType (which would be int). It should be (model.GetTypeInfo(implicitArrayCreation).Type as IArrayTypeSymbol)?.ElementType

[Tim-Pohlmann]

good catch!

[Tim-Pohlmann]

maybe more UTs are required then.

[mary-georgiou-sonarsource]

Done

[martin-strecker-sonarsource]

Do the UTs cover differences in the array rank? I don't think so, and maybe the implementation as well:

void Method(params object[] args) { }

Method(new object[] { null }); // Noncompliant
// These cases might be FPs
Method(new object[,] { { null } }); // Compliant
Method(new[,] { { new object() } }); // Compliant

// This should work
Method(new object[][] { new[] { new object() } }); // Compliant

params array must be single-dimensional.

[mary-georgiou-sonarsource]

We cover only jagged arrays.

[martin-strecker-sonarsource]

Suggested change

	Method(new [] { 1, 2, 3, }); // Compliant, Elements in args: [System.Int32[]]
	Method(new[] { 1, 2, 3, }); // Compliant, Elements in args: [System.Int32[]]

[martin-strecker-sonarsource]

Add one more test with a multidimensional array

Suggested change

	Method(new [] { 1, 2, 3, }); // Compliant, Elements in args: [System.Int32[]]
	Method(new[] { 1, 2, 3, }); // Compliant, Elements in args: [System.Int32[]]
	Method(new[,] { { 1, 2 } }); // Compliant, Elements in args: [System.Int32[,]]

[sonarcloud]

Quality Gate passed for 'Sonar .NET Java Plugin'

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[sonarcloud]

Quality Gate passed for 'SonarAnalyzer for .NET'

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
71.4% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[martin-strecker-sonarsource]

Approved, because the cases left are edge cases, but there seems to be something wrong with the implementation. I think there is some special handling with object[] params and I'm not sure, we handle multi-dimensional arrays properly.
You may want to have another look later.

[martin-strecker-sonarsource]

Why is Method(new String[] { "1", "2" }); Noncompliant, while Method(new object[] { null }); is compliant? This looks like an FN to me.