Roslyn 5.0.0

[christophwille]

dotnet/roslyn#80213

#3539

[christophwille]

Supersedes #3517

[Copilot]

Pull request overview

This PR upgrades the Roslyn compiler packages from version 4.14.0 to 5.0.0 and implements support for C# 14's first-class span types feature. The changes introduce a new language feature that treats Span<T> and ReadOnlySpan<T> as built-in types with special conversion rules.

Key changes:

• Roslyn package upgrade from 4.14.0 to 5.0.0
• Implementation of implicit span conversions and type inference for span types
• New decompiler setting to enable/disable first-class span type treatment
• Updates to method resolution, overload resolution, and conversion logic to support span conversions

Reviewed changes

Copilot reviewed 14 out of 15 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
Directory.Packages.props	Upgrades Microsoft.CodeAnalysis packages from 4.14.0 to 5.0.0
ILSpy/Properties/Resources.resx	Adds resource string for FirstClassSpanTypes setting
ICSharpCode.Decompiler/DecompilerSettings.cs	Adds FirstClassSpanTypes property and integrates it with language version detection
ICSharpCode.Decompiler/TypeSystem/ICompilation.cs	Adds TypeSystemOptions property to interface
ICSharpCode.Decompiler/TypeSystem/Implementation/SimpleCompilation.cs	Implements TypeSystemOptions property with default value
ICSharpCode.Decompiler/TypeSystem/DecompilerTypeSystem.cs	Adds FirstClassSpanTypes flag to TypeSystemOptions enum and updates initialization logic
ICSharpCode.Decompiler/Semantics/Conversion.cs	Adds ImplicitSpanConversion type and related properties
ICSharpCode.Decompiler/CSharp/Resolver/CSharpConversions.cs	Implements implicit span conversion logic and updates better conversion logic
ICSharpCode.Decompiler/CSharp/Resolver/TypeInference.cs	Updates type inference to handle span conversions in MakeExactInference and MakeLowerBoundInference
ICSharpCode.Decompiler/CSharp/Resolver/OverloadResolution.cs	Updates extension method validation to allow span conversions
ICSharpCode.Decompiler/CSharp/Resolver/CSharpResolver.cs	Updates extension method eligibility check to include span conversions
ICSharpCode.Decompiler/CSharp/CallBuilder.cs	Updates method comparison to use TypeErasure
ICSharpCode.Decompiler.Tests/PrettyTestRunner.cs	Enables nullable for ExtensionProperties test
ICSharpCode.Decompiler.Tests/Helpers/Tester.cs	Updates default language version from CSharp13_0 to CSharp14_0

Files not reviewed (1)

• ILSpy/Properties/Resources.Designer.cs: Language not supported

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[Copilot]

[nitpick] The logical OR operation spans multiple lines without clear visual separation. Consider extracting this complex boolean expression into a well-named local variable or helper method to improve readability, such as bool hasValidConversion = IdentityConversion(...) || IsImplicitReferenceConversion(...);

Suggested change

	return IdentityConversion(elementType, toType.TypeArguments[0])
	|| IsImplicitReferenceConversion(elementType, toType.TypeArguments[0]);
	bool hasValidConversion = IdentityConversion(elementType, toType.TypeArguments[0])
	|| IsImplicitReferenceConversion(elementType, toType.TypeArguments[0]);
	return hasValidConversion;

[Copilot]

This is duplicated logic from lines 1258-1259. Consider extracting this into a helper method like bool HasIdentityOrImplicitReferenceConversion(IType from, IType to) to reduce code duplication.