ProcessStartInfo.ArgumentList does not exist on net472, which the component tests
also target on Windows CI. Build the quoted argument string by hand instead.

xunit 3.2.2 no longer discovers internal test classes, so the module was
silently skipped after rebasing onto current main (pre-existing internal test
modules like CompilerService.Caches are likewise undiscovered there). Public
visibility restores discovery; 17 tests run and pass.

Add internal generated-name normalization and synthesized-name map replay support as a standalone slice. The new map state is side-channel based, all new compiler modules remain internal, and CompilerGlobalState preserves the existing no-map counter path while checking an accessor captured once per compiler state.

Route existing IlxGen generated-name allocations through inert helper wrappers, add pure name-map and normalizer tests, add a normal compilation determinism guard over emitted generated names, and document the extracted seams in P5_REPORT.md.

Verification: built FSharp.Compiler.Service, FSharp.Compiler.Service.Tests, FSharp.Compiler.ComponentTests, and FSharpSuite.Tests in Release; ran the migrated service test classes, the component determinism class, FSharpSuite DeterministicTests, and the FCS SurfaceArea class successfully.

Adds an internal, standalone ECMA-335 Edit-and-Continue metadata delta writer to
AbstractIL: delta #- table stream and heap construction (DeltaMetadataTables,
DeltaMetadataSerializer, DeltaTableLayout, DeltaIndexSizing), ECMA-335 II.24.2.6
coded-index encoding (DeltaMetadataEncoding), EncLog/EncMap emission, generation GUID
chaining, user-string and standalone-signature token calculators (IlxDeltaStreams),
and the coordinating writer (FSharpDeltaMetadataWriter) over a plain row-description
input model (DeltaMetadataTypes, ILDeltaHandles, ILMetadataHeaps).

The writer's inputs are row records (names, tokens, signatures, RVAs) plus heap
offsets; it has no dependency on any semantic diffing or session machinery. It
compiles with no in-tree consumer by design: the consumer is the F# hot reload work
in dotnet#19941, following the same upstreaming pattern as dotnet#20017 and dotnet#20018
(land isolated, test-covered infrastructure first, wire the feature in a later PR).

One line of ilwrite.fsi is touched to expose the pre-existing markerForUnicodeBytes
so the delta writer reuses the exact string-marker logic of the full writer. No
behavior change for any existing code path.

Tests (130): coded-index encodings asserted against the production definitions and
ECMA-335 II.24.2.6 order, System.Reflection.Metadata reader parity over emitted
deltas, EncLog/EncMap correctness, stream layout, heap and index sizing,
multi-generation heap-offset chaining asserted against computed expected values,
standalone-signature rows asserted at baseline+1 from a real seeded baseline, and
serializer failure paths.

…CI images

The Roslyn cross-validation test shells out to dotnet build to produce a
real Roslyn PDB. The process launch had two problems. It computed the
host path by hand from __SOURCE_DIRECTORY__, which misses on CI images
that carry no repo-local .dotnet at that depth, failing with
Win32Exception before the build starts. It also left UseShellExecute at
its default, which is true on net472 and rejects redirected streams, so
every Desktop test leg failed deterministically with
InvalidOperationException.

Resolve the host like the rest of the test framework via
TestFramework.initialConfig.DotNetExe, which prefers the repo-local
.dotnet and falls back to PATH, and set UseShellExecute to false
explicitly.

Verified: FSharp.Compiler.ComponentTests builds clean;
EncMethodDebugInformationTests 17 passed, 0 failed (net10.0); fantomas
clean on the touched file.

Add an internal TypedTreeDiff module that snapshots CheckedImplFile bindings and entities, then classifies body, signature, inline, declaration add/remove, and type layout changes without depending on hot reload sessions, runtime capability negotiation, EnC capability names, baseline state, or delta emission.

Add focused FCS tests for unchanged/reference-equal files, body edits, signature edits, additions, deletions, layout changes, and logical-name arity handling. Wire the module and tests into compile order, add a release note, and include P6_REPORT.md.

Verification:

- ./.dotnet/dotnet build src/Compiler/FSharp.Compiler.Service.fsproj -c Debug /p:BUILDING_USING_DOTNET=true

- ./.dotnet/dotnet test tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj -c Debug /p:BUILDING_USING_DOTNET=true -- --filter-class "*TypedTreeDiffTests*"

- ./.dotnet/dotnet test tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj -c Debug /p:BUILDING_USING_DOTNET=true -- --filter-class "*SurfaceAreaTest*"

…0260717/hotreload-baseline-reader

Add standalone baseline PE and portable PDB readers for hot reload, including token maps and MVID/PDB table snapshots.

Carry the F# synthesized-name snapshot module CDI codec and portable PDB read path, with recorded snapshots taking precedence over IL reconstruction.

Add focused component tests for snapshot round-trip, direct module CDI reading, baseline token maps, recorded fallback behavior, and EnC closure-name reconstruction.

…erload

CI compiles the snapshot round-trip and baseline reader tests with
FS0193: the explicit Assert.Equal<string> type application commits
overload resolution to the scalar Equal(T, T) shape while both
arguments are string arrays. Use Assert.Equal<string[]>, the form the
neighboring name-map tests already use, so resolution lands on the
structural array comparison everywhere.

Verified: FSharp.Compiler.ComponentTests builds clean;
EncMethodDebugInformationTests 22 passed, 0 failed (net10.0); fantomas
clean on the touched file.

…/20260717/hotreload-delta-emitter

…h/20260717/hotreload-delta-emitter

Add the internal hot reload delta emitter, symbol matcher, and direct emitter tests.

Keep session and service integration deferred.

…cation

This slice carries the full typed-tree differ, which treats a
parameter-type change as a removal plus an insert of distinct symbols
rather than one matched symbol with a changed signature. The removal
surfaces as the rude edit (DeclarationRemoved) and the replacement as
an insert semantic edit, so the earlier expectations (no semantic
edits, SignatureChange) no longer describe this tree. Assert the
observable contract instead: exactly one rude edit with the removal
classification. Hosts reject the whole update when any rude edit is
present, so the accompanying insert never applies.

Verified: TypedTreeDiffTests 8 passed 0 failed, fantomas clean on the
touched file.

Verified the repository-wide Fantomas check, the service test project build with zero warnings and errors, and all 134 DeltaMetadata tests.

Carries lower-slice formatting into the session branch and verifies the complete repository with Fantomas.

…eload-session