[WIP] Fix DelegateBodyTests to ensure UseProvidedBody accepts any body by Copilot · Pull Request #94 · dex3r/EasySourceGenerators

Copilot · 2026-03-25T15:14:42Z

Original prompt

This section details on the original issue you should resolve

<issue_title>UseProvidedBody should accept any body</issue_title>
<issue_description>Look at the newly added DelegateBodyTests tests. They are failing, your job is to write generators code to make them pass. Feel free to edit them a tiny little bit (like formatting) if there is a mistake in the tests.

The UseProvidedBody accepts a delegate. This delegate code, no matter the complexity (could be simple return, could be hundreds of lines) should end up as a body for the target method. The code in this delegate should be more-or-less copied exactly as is to the target method body.</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes UseProvidedBody should accept any body #93

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codecov · 2026-03-25T15:27:43Z

Codecov Report

❌ Patch coverage is 8.73016% with 115 lines in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...crementalGenerators/DelegateBodySyntaxExtractor.cs	10.41%	85 Missing and 1 partial ⚠️
...talGenerators/GeneratesMethodGenerationPipeline.cs	5.26%	17 Missing and 1 partial ⚠️
...ators/SourceEmitting/PartialMethodSourceEmitter.cs	0.00%	7 Missing ⚠️
...lGenerators/GeneratesMethodPatternSourceBuilder.cs	0.00%	4 Missing ⚠️

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…neration Add DelegateBodySyntaxExtractor to extract lambda body from syntax tree. Support both expression lambdas (e.g. () => 42) and block lambdas with complex control flow (if/else, switch, multi-statement bodies). Add EmitWithBody to PartialMethodSourceEmitter for arbitrary body emission. Fix test lambda parameter names to match actual method parameters. Co-authored-by: dex3r <3155725+dex3r@users.noreply.github.com> Agent-Logs-Url: https://github.com/dex3r/EasySourceGenerators/sessions/e1b5542a-d819-423d-a4b7-f97407a7d1b4

Copilot

Pull request overview

This PR aims to fix failing DelegateBodyTests by making fluent UseProvidedBody(...) delegate bodies get emitted into the generated partial method “as written”, preferring syntax-based extraction over runtime execution.

Changes:

Added syntax-tree extraction of UseProvidedBody(...) lambda bodies and emit support for arbitrary method bodies.
Updated the fluent generation pipeline to try syntax extraction first, falling back to runtime execution if not found.
Updated tests/examples and extended the fluent builder API surface (compile-time constants staging).

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
EasySourceGenerators.sln.DotSettings.user	Adds Rider/ReSharper user settings entry.
EasySourceGenerators.Tests/EasySourceGenerators.Tests.csproj	Adds `System.Text` as a global using for tests.
EasySourceGenerators.Tests/DelegateBodyTests.cs	Fixes lambda parameter naming and expected body formatting to match emitted bodies.
EasySourceGenerators.Generators/SourceEmitting/PartialMethodSourceEmitter.cs	Adds `EmitWithBody` to emit arbitrary method bodies.
EasySourceGenerators.Generators/IncrementalGenerators/GeneratesMethodPatternSourceBuilder.cs	Adds `GeneratePartialMethodWithBody` wrapper around `EmitWithBody`.
EasySourceGenerators.Generators/IncrementalGenerators/GeneratesMethodGenerationPipeline.cs	Attempts delegate-body syntax extraction before runtime execution; adds delegate-body formatting helper.
EasySourceGenerators.Generators/IncrementalGenerators/DelegateBodySyntaxExtractor.cs	New extractor to pull lambda bodies from `UseProvidedBody(...)` calls and re-indent them.
EasySourceGenerators.Generators/DataBuilding/DataRecords.cs	Extends `BodyGenerationData` with `CompileTimeConstants`.
EasySourceGenerators.Generators/DataBuilding/DataMethodBodyBuilders.cs	Removes old `BodyWithSwitchStatement` stub/commented plan block.
EasySourceGenerators.Examples/PiExampleFluent.cs	Removes the old commented-out fluent PI example.
EasySourceGenerators.Examples/PiExample.cs	Introduces a new fluent PI example using `WithCompileTimeConstants` + `UseProvidedBody`.
EasySourceGenerators.Abstractions/MethodBody/IMethodBodyBuilder.cs	Adds `WithCompileTimeConstants` and new stage-5 interfaces/overloads.

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Copilot · 2026-03-25T16:04:34Z

EasySourceGenerators.Examples/PiExample.cs

+    static IMethodBodyGenerator GetPiDecimal_Generator() =>
+        Generate.MethodBody()
+            .ForMethod().WithReturnType<int>().WithParameter<int>()
+            .WithCompileTimeConstants(() => new
+            {
+                PrecomputedTargets = (new int[] { 0, 1, 2, 300, 301, 302, 303 }).ToDictionary(i => i, i => SlowMath.CalculatePiDecimal(i))
+            })
+            .UseProvidedBody((constants, decimalNumber) =>


WithCompileTimeConstants(...) is used here, but there is currently no implementation of that method in the concrete fluent builder stages (search shows it exists only in the interface and this example). This will prevent the Examples project/solution from compiling until the builder/runtime support for compile-time constants is added end-to-end.

Copilot · 2026-03-25T16:04:34Z

EasySourceGenerators.Generators/IncrementalGenerators/GeneratesMethodGenerationPipeline.cs

+        bool isBlockBody = delegateBody.Contains("\n");
+
+        if (isBlockBody)
+        {
+            return delegateBody;
+        }
+
+        if (isVoidReturn)
+        {
+            return $"        {delegateBody};";
+        }
+
+        return $"        return {delegateBody};";


FormatDelegateBodyForEmit determines whether the extracted lambda was a block by checking delegateBody.Contains("\n"). DelegateBodySyntaxExtractor trims trailing newlines, so a single-statement block lambda can produce a body with no \n and will be treated as an expression body, resulting in invalid emitted code (e.g., double return or ;). Consider returning a (body, kind) result from the extractor (expression vs block), or otherwise passing an explicit flag so block bodies are never inferred via newline presence.

Suggested change

bool isBlockBody = delegateBody.Contains("\n");

if (isBlockBody)

{

return delegateBody;

}

if (isVoidReturn)

{

return $" {delegateBody};";

}

return $" return {delegateBody};";

// Treat the body as a block/statement body if it spans multiple lines or already

// appears to be a complete statement (e.g., ends with a semicolon). This avoids

// misclassifying single-statement block lambdas (like "return x;") as expression

// bodies, which would otherwise lead to invalid emitted code (double "return" or ";").

string trimmedBody = delegateBody.TrimEnd();

bool isBlockBody = trimmedBody.Contains("\n") || trimmedBody.EndsWith(";");

if (isBlockBody)

{

// For block/statement bodies, use the text as provided by the extractor.

return delegateBody;

}

if (isVoidReturn)

{

return $" {trimmedBody};";

}

return $" return {trimmedBody};";

Copilot · 2026-03-25T16:04:35Z

EasySourceGenerators.Generators/IncrementalGenerators/DelegateBodySyntaxExtractor.cs

+        for (int i = 0; i < lines.Length; i++)
+        {
+            if (openIndex == -1 && lines[i].TrimEnd().EndsWith("{", StringComparison.Ordinal))
+            {
+                openIndex = i;


ExtractBlockBody relies on finding {/} on their own lines via EndsWith("{") / StartsWith("}"). This fails for single-line block lambdas like x => { return 42; }, causing extraction to return null and the generator to fall back to runtime execution (which doesn't preserve arbitrary bodies). Consider extracting the span between block.OpenBraceToken and block.CloseBraceToken (or using tokens/statement list) rather than line-scanning the formatted text.

Copilot · 2026-03-25T16:04:35Z

EasySourceGenerators.Generators/IncrementalGenerators/DelegateBodySyntaxExtractor.cs

+    /// <summary>
+    /// Attempts to find a <c>UseProvidedBody(...)</c> call in the given generator method syntax
+    /// and extract the lambda body. Returns <c>null</c> if no such call is found.
+    /// For expression lambdas, returns a single <c>return {expr};</c> line.


The XML doc on TryExtractDelegateBody says expression lambdas return a full return {expr}; line, but the implementation returns only the expression text (wrapping happens later in FormatDelegateBodyForEmit). Update the comment to reflect the actual return value to avoid future misuse.

Suggested change

/// For expression lambdas, returns a single <c>return {expr};</c> line.

/// For expression lambdas, returns the expression text (wrapping into a <c>return {expr};</c>

/// statement is performed later when emitting the method body).

Copilot · 2026-03-25T16:04:35Z

EasySourceGenerators.Generators/DataBuilding/DataMethodBodyBuilders.cs

 public record DataMethodBodyBuilderStage4<TParam1, TReturnType>(BodyGenerationData Data) : IMethodBodyBuilderStage4<TParam1, TReturnType>
 {
    public IMethodBodyGenerator UseProvidedBody(Func<TParam1, TReturnType> body) => new DataMethodBodyGenerator(Data with { RuntimeDelegateBody = body });

    public IMethodBodyGenerator BodyReturningConstant(Func<TReturnType> constantValueFactory) =>


IMethodBodyBuilderStage4* interfaces now include WithCompileTimeConstants(...), but the concrete builder stages here (e.g., DataMethodBodyBuilderStage4<TParam1, TReturnType>) do not implement that member (nor the new stage-5 types). As written, this will not compile once the updated interfaces are referenced. Add the WithCompileTimeConstants implementations and the corresponding stage-5 builder records, and ensure they populate BodyGenerationData appropriately.

Copilot · 2026-03-25T16:04:36Z

EasySourceGenerators.sln.DotSettings.user

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 	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=7020124F_002D9FFC_002D4AC3_002D8F3D_002DAAB8E0240759_002Ff_003ACSharpCompilationReference_002Ecs_002Fl_003AC_0021_003FUsers_003Fdex3r_003FAppData_003FRoaming_003FJetBrains_003FRider2025_002E3_003Fresharper_002Dhost_003FSourcesCache_003Fd18742e05d9d34467e6d756ef95f2def337dc61bd1678295c715359e839bb5_003FCSharpCompilationReference_002Ecs/@EntryIndexedValue">ForceIncluded</s:String>
 	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=7020124F_002D9FFC_002D4AC3_002D8F3D_002DAAB8E0240759_002Ff_003AGeneratorAttribute_002Ecs_002Fl_003AC_0021_003FUsers_003Fdex3r_003FAppData_003FRoaming_003FJetBrains_003FRider2025_002E3_003Fresharper_002Dhost_003FSourcesCache_003Ff1fac3c62ca6565cc950105beae419771ba372ddd8be9ee61ee7edba4bcc22_003FGeneratorAttribute_002Ecs/@EntryIndexedValue">ForceIncluded</s:String>
+	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=7020124F_002D9FFC_002D4AC3_002D8F3D_002DAAB8E0240759_002Ff_003AObject_002Ecs_002Fl_003AC_0021_003FUsers_003Fdex3r_003FAppData_003FRoaming_003FJetBrains_003FRider2025_002E3_003Fresharper_002Dhost_003FDecompilerCache_003Fdecompiler_003F51505665371d472f8bdbc333fa4d888cf49938_003Fc8_003F5d7360d0_003FObject_002Ecs/@EntryIndexedValue">ForceIncluded</s:String>


This .DotSettings.user file contains IDE/user-specific configuration (including machine-specific cache paths). These files typically shouldn't be committed because they create noisy diffs and are not portable across environments. Consider removing it from the repo/PR and adding it to .gitignore (or using a non-.user shared settings file if you need team-wide defaults).

Copilot AI assigned Copilot and dex3r Mar 25, 2026

Copilot started work on behalf of dex3r March 25, 2026 15:14 View session

dex3r closed this Mar 25, 2026

dex3r force-pushed the copilot/fix-delegate-body-tests branch from 90d0e3d to 0bce1ab Compare March 25, 2026 15:30

Copilot AI and others added 2 commits March 25, 2026 15:30

Initial plan

0604630

Copilot AI requested a review from dex3r March 25, 2026 15:31

dex3r reopened this Mar 25, 2026

Copilot stopped work on behalf of dex3r due to an error March 25, 2026 15:31
The session was cancelled by the user.

dex3r added 2 commits March 25, 2026 16:56

Compile time constats WIP

53d5d99

Compile time constants WIP

adb47c0

dex3r approved these changes Mar 25, 2026

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dex3r marked this pull request as ready for review March 25, 2026 15:59

Copilot AI review requested due to automatic review settings March 25, 2026 15:59

dex3r merged commit 651af09 into feature/metehod_template Mar 25, 2026
1 of 2 checks passed

dex3r deleted the copilot/fix-delegate-body-tests branch March 25, 2026 15:59

Copilot started reviewing on behalf of dex3r March 25, 2026 15:59 View session

dex3r mentioned this pull request Mar 25, 2026

Remove looking for body statement #95

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Copilot AI mentioned this pull request Mar 25, 2026

Remove UseProvidedBody string matching from DelegateBodySyntaxExtractor #96

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Copilot AI reviewed Mar 25, 2026

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[WIP] Fix DelegateBodyTests to ensure UseProvidedBody accepts any body#94

[WIP] Fix DelegateBodyTests to ensure UseProvidedBody accepts any body#94
dex3r merged 4 commits intofeature/metehod_templatefrom
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	/// For expression lambdas, returns a single <c>return {expr};</c> line.
	/// For expression lambdas, returns the expression text (wrapping into a <c>return {expr};</c>
	/// statement is performed later when emitting the method body).

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