Improve UseMemberBody and add new diagnostics

[PhenX]

Fixes #134

[Copilot]

Pull request overview

This PR addresses issue #134 by improving [Projectable(UseMemberBody = ...)] support for method scenarios (including extension methods) and adding clearer generator diagnostics plus documentation/tests around the feature.

Changes:

• Add generator diagnostics EFP0010 (member not found) and EFP0011 (incompatible member) for UseMemberBody.
• Extend generator/test coverage for UseMemberBody with methods, properties, and Expression<Func<...>>-backed bodies (including extension methods), plus functional coverage.
• Update README to document UseMemberBody usage patterns and diagnostics.

Reviewed changes

Copilot reviewed 22 out of 22 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
tests/EntityFrameworkCore.Projectables.Generator.Tests/UseMemberBodyTests.cs	New generator tests covering valid/invalid UseMemberBody scenarios.
tests/EntityFrameworkCore.Projectables.Generator.Tests/UseMemberBodyTests.Method_UsesMethodBody_SameReturnType.verified.txt	Snapshot for generated output from redirected body case.
tests/EntityFrameworkCore.Projectables.Generator.Tests/UseMemberBodyTests.Method_UsesExpressionPropertyBody_StaticExtension.verified.txt	Snapshot for generated output when backing an extension method via Expression<Func<...>> property.
tests/EntityFrameworkCore.Projectables.Generator.Tests/UseMemberBodyTests.Method_UsesExpressionPropertyBody_InstanceMethod.verified.txt	Snapshot for generated output when backing an instance method via Expression<Func<...>> property.
tests/EntityFrameworkCore.Projectables.Generator.Tests/UseMemberBodyTests.Property_UsesPropertyBody_SameType.verified.txt	Snapshot for generated output when redirecting a property body.
tests/EntityFrameworkCore.Projectables.Generator.Tests/UseMemberBodyTests.StaticMethod_UsesStaticMethodBody.verified.txt	Snapshot for generated output when redirecting a static method body.
tests/EntityFrameworkCore.Projectables.Generator.Tests/ExtensionMethodTests.cs	Adds a generator test for extension methods backed by an expression property body.
tests/EntityFrameworkCore.Projectables.Generator.Tests/ExtensionMethodTests.ProjectableExtensionMethod_WithExpressionPropertyBody.verified.txt	Snapshot for new extension-method test output.
tests/EntityFrameworkCore.Projectables.FunctionalTests/ExtensionsMethods/ExtensionMethodTests.cs	Adds functional test ensuring EF SQL translation works with expression-property-backed extension methods.
tests/EntityFrameworkCore.Projectables.FunctionalTests/ExtensionsMethods/ExtensionMethodTests.ExtensionMethod_WithExpressionPropertyBody.verified.txt	Functional snapshot (default TFM) for the new query translation.
tests/EntityFrameworkCore.Projectables.FunctionalTests/ExtensionsMethods/ExtensionMethodTests.ExtensionMethod_WithExpressionPropertyBody.DotNet9_0.verified.txt	Functional snapshot for .NET 9.
tests/EntityFrameworkCore.Projectables.FunctionalTests/ExtensionsMethods/ExtensionMethodTests.ExtensionMethod_WithExpressionPropertyBody.DotNet10_0.verified.txt	Functional snapshot for .NET 10.
tests/EntityFrameworkCore.Projectables.FunctionalTests/ExtensionsMethods/ExtensionMethodTests.ExtensionMethodAcceptingDbContext.verified.txt	Updates expected SQL projection due to model change (new Name column).
tests/EntityFrameworkCore.Projectables.FunctionalTests/ExtensionsMethods/ExtensionMethodTests.ExtensionMethodAcceptingDbContext.DotNet9_0.verified.txt	Same snapshot update for .NET 9.
tests/EntityFrameworkCore.Projectables.FunctionalTests/ExtensionsMethods/ExtensionMethodTests.ExtensionMethodAcceptingDbContext.DotNet10_0.verified.txt	Same snapshot update for .NET 10.
tests/EntityFrameworkCore.Projectables.FunctionalTests/ExtensionsMethods/EntityExtensions.cs	Adds NameEquals projectable extension method using UseMemberBody and an expression-property body.
tests/EntityFrameworkCore.Projectables.FunctionalTests/ExtensionsMethods/Entity.cs	Adds nullable Name to the functional-test entity model.
src/EntityFrameworkCore.Projectables/Services/ProjectionExpressionResolver.cs	Adjusts runtime UseMemberBody expression-property resolution logic for static methods.
src/EntityFrameworkCore.Projectables.Generator/ProjectableInterpreter.cs	Implements generator-side UseMemberBody candidate selection, expression-property handling for methods, and diagnostic emission.
src/EntityFrameworkCore.Projectables.Generator/Diagnostics.cs	Adds descriptors for EFP0010/EFP0011.
src/EntityFrameworkCore.Projectables.Generator/AnalyzerReleases.Shipped.md	Documents new diagnostics in shipped analyzer rules list.
README.md	Adds UseMemberBody documentation, examples, and diagnostic reference.

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[Copilot]

Pull request overview

Copilot reviewed 29 out of 29 changed files in this pull request and generated 5 comments.

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Pull request overview

Copilot reviewed 29 out of 29 changed files in this pull request and generated 3 comments.

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[Copilot]

TryApplyExpressionPropertyBody extracts only the inner lambda body and then generates a new parameter list from the method signature. If the expression property's lambda uses different parameter identifiers (e.g. x => x.Value > 0 for an instance method where the generated parameter is @this), the generated code will not compile, and no EFP0011 diagnostic is produced. Consider either rewriting lambda-parameter identifiers to the generated parameters (by symbol), or validating the lambda parameter names and emitting a dedicated diagnostic when they don't match.

[Copilot]

SetupGenericTypeParameters skips emitting a constraint clause when tp.ConstraintTypes is empty (line 245), but Roslyn represents class, struct, notnull, and new() constraints via flags (HasReferenceTypeConstraint, etc.) even when ConstraintTypes is empty. This means type parameters constrained only by those flags won't have their constraints emitted into the generated class. Consider emitting a constraint clause whenever any constraint flag is present (or any constraint types exist).

Suggested change

	if (tp.ConstraintTypes.IsDefaultOrEmpty)
	var hasAnyConstraints =
	!tp.ConstraintTypes.IsDefaultOrEmpty ||
	tp.HasReferenceTypeConstraint ||
	tp.HasValueTypeConstraint ||
	tp.HasNotNullConstraint ||
	tp.HasConstructorConstraint;
	if (!hasAnyConstraints)

[Copilot]

GetProperty(... BindingFlags.Static | BindingFlags.Instance ...) can return an instance property, but GetValue(null) will then throw TargetException instead of returning null. Either restrict lookup to static properties (and/or validate exprProperty.GetGetMethod(true)?.IsStatic) or safely handle instance properties to avoid a runtime crash when UseMemberBody points at a non-static expression property.

Suggested change

	if (exprProperty?.GetValue(null) is not LambdaExpression lambda)
	// Only static properties can be accessed with a null target; ignore instance properties to avoid TargetException.
	var getter = exprProperty?.GetGetMethod(true);
	if (getter is null || !getter.IsStatic || exprProperty.GetValue(null) is not LambdaExpression lambda)