Fix seq try-with handler body executing twice (#19660) (#19661)

Guard disposeOriginal() against accessing a faulted Lazy<T> in
EnumerateTryWith. When source.GetEnumerator() throws, the Lazy
caches the exception and re-throws on every .Value access, causing
the disposal path to re-trigger moveExceptionHandler.

Add IsValueCreated check so disposal is skipped when no enumerator
was successfully created.

Fixes #19660

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Fix flaky async/task tests under CI load (#19632)

- AsyncType.CreateTask: increase waitASec timeout from 1s to 30s
  (thread pool saturation on loaded CI prevents scheduling trivial tasks)

- Tasks/TasksDynamic testNonBlocking: replace Thread.Sleep(100) race
  with ManualResetEventSlim gate for deterministic synchronization

- Tasks/TasksDynamic testExceptionThrownInFinally: wire up the
  already-declared-but-unused stepOutside SemaphoreSlim instead of
  Thread.Sleep(100) race (matching test2ndExceptionThrownInFinally pattern)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

[release/dev18.0] Update dependencies from dotnet/roslyn (#19524)

* Update dependencies from https://github.com/dotnet/roslyn build 20260330.2
On relative base path root
Microsoft.CodeAnalysis , Microsoft.CodeAnalysis.Compilers , Microsoft.CodeAnalysis.CSharp , Microsoft.CodeAnalysis.EditorFeatures , Microsoft.CodeAnalysis.EditorFeatures.Text , Microsoft.CodeAnalysis.ExternalAccess.FSharp , Microsoft.CodeAnalysis.Features , Microsoft.VisualStudio.LanguageServices From Version 5.0.0-2.26175.11 -> To Version 5.0.0-2.26180.2

* Update dependencies from https://github.com/dotnet/roslyn build 20260401.2
On relative base path root
Microsoft.CodeAnalysis , Microsoft.CodeAnalysis.Compilers , Microsoft.CodeAnalysis.CSharp , Microsoft.CodeAnalysis.EditorFeatures , Microsoft.CodeAnalysis.EditorFeatures.Text , Microsoft.CodeAnalysis.ExternalAccess.FSharp , Microsoft.CodeAnalysis.Features , Microsoft.VisualStudio.LanguageServices From Version 5.0.0-2.26175.11 -> To Version 5.0.0-2.26201.2

* Update dependencies from https://github.com/dotnet/roslyn build 20260402.6
On relative base path root
Microsoft.CodeAnalysis , Microsoft.CodeAnalysis.Compilers , Microsoft.CodeAnalysis.CSharp , Microsoft.CodeAnalysis.EditorFeatures , Microsoft.CodeAnalysis.EditorFeatures.Text , Microsoft.CodeAnalysis.ExternalAccess.FSharp , Microsoft.CodeAnalysis.Features , Microsoft.VisualStudio.LanguageServices From Version 5.0.0-2.26175.11 -> To Version 5.0.0-2.26202.6

* Fix CancellationPropagatesToTask test disposing running Task

Change 'use t' to 'let t' to avoid calling Dispose on a Task that
may still be running, which throws InvalidOperationException on .NET 10.

Replace 'waitASec t' (1-second timeout) with 't.Wait()' to wait for
cancellation to fully propagate, matching the pattern used by the
sibling CancellationPropagatesToGroup test.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: dotnet-maestro[bot] <dotnet-maestro[bot]@users.noreply.github.com>
Co-authored-by: Tomas Grosup <tomasgrosup@microsoft.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Tomas Grosup <Tomas.Grosup@gmail.com>

Add regression test: #3660, array of functions invocation correctness (…

…#19479)

* Add regression test for #3660: array of functions invocation without closure allocation

- Runtime correctness test: compiles and runs the indexed array function
  invocation pattern, verifying correct results
- IL verification test: compiles runAll as a library with optimizations and
  asserts no closure class (extending FSharpFunc) is emitted, ensuring the
  compiler does not generate needless allocations for fArr.[i] x

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Apply suggestions from code review

Co-authored-by: Adam Boniecki <20281641+abonie@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Adam Boniecki <20281641+abonie@users.noreply.github.com>

Add regression test: #3660, array of functions invocation correctness (…

…#19479)

* Add regression test for #3660: array of functions invocation without closure allocation

- Runtime correctness test: compiles and runs the indexed array function
  invocation pattern, verifying correct results
- IL verification test: compiles runAll as a library with optimizations and
  asserts no closure class (extending FSharpFunc) is emitted, ensuring the
  compiler does not generate needless allocations for fArr.[i] x

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Apply suggestions from code review

Co-authored-by: Adam Boniecki <20281641+abonie@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Adam Boniecki <20281641+abonie@users.noreply.github.com>

FCS: capture additional types during analysis (#19305)

FCS: capture additional types during analysis (#19305)

FCS: capture additional types during analysis (#19305)

Bugfix :: Coloring for case testers and with (#19311)

Bugfix :: Coloring for case testers and with (#19311)