Don't cause index out of range exn in completion (#17227)

* Don't cause index out of range exn in completion

* Dotting into delegates with multiple type arguments would trigger an
  index out of range exception. Now it doesn't.

* Update release notes

docs/release-notes/.FSharp.Compiler.Service/8.0.400.md

@@ -1,5 +1,6 @@
 ### Fixed
 
+* Fix internal error when dotting into delegates with multiple type parameters. ([PR #17227](https://github.com/dotnet/fsharp/pull/17227))
 * Error for partial implementation of interface with static and non-static abstract members. ([Issue #17138](https://github.com/dotnet/fsharp/issues/17138), [PR #17160](https://github.com/dotnet/fsharp/pull/17160))
 * Optimize simple mappings with preludes in computed collections. ([PR #17067](https://github.com/dotnet/fsharp/pull/17067))
 * Improve error reporting for abstract members when used in classes. ([PR #17063](https://github.com/dotnet/fsharp/pull/17063))
@@ -24,4 +25,4 @@
 * Minor compiler perf improvements. ([PR #17130](https://github.com/dotnet/fsharp/pull/17130))
 * Improve error of Active Pattern case Argument Count Not Match ([PR #16846](https://github.com/dotnet/fsharp/pull/16846))
 * AsyncLocal diagnostics context. ([PR #16779](https://github.com/dotnet/fsharp/pull/16779))
-* Reduce allocations in compiler checking via `ValueOption` usage ([PR #16822](https://github.com/dotnet/fsharp/pull/16822))
+* Reduce allocations in compiler checking via `ValueOption` usage ([PR #16822](https://github.com/dotnet/fsharp/pull/16822))

src/Compiler/Checking/NameResolution.fs

@@ -1105,7 +1105,7 @@ let GetNestedTyconRefsOfType (infoReader: InfoReader) (amap: Import.ImportMap) (
 /// Handle the .NET/C# business where nested generic types implicitly accumulate the type parameters
 /// from their enclosing types.
 let MakeNestedType (ncenv: NameResolver) (tinst: TType list) m (tcrefNested: TyconRef) =
- let tps = match tcrefNested.Typars m with [] -> [] | l -> List.skip tinst.Length l
+ let tps = match tcrefNested.Typars m with [] -> [] | l -> l[tinst.Length..]
  let tinstNested = ncenv.InstantiationGenerator m tps
  mkAppTy tcrefNested (tinst @ tinstNested)