Don't touch library-only stuff for 'remove parens' diagnostics(#16244)

Author: brianrourkeboll

src/Compiler/Service/ServiceAnalysis.fs

@@ -1103,6 +1103,14 @@ module UnnecessaryParentheses =
             //     let inline f x = (^a : (static member Parse : string -> ^a) x)
             | SynExpr.Paren(expr = SynExpr.TraitCall _), _ -> ValueNone
 
+            // Don't touch library-only stuff:
+            //
+            //     (# "ldlen.multi 2 0" array : int #)
+            | SynExpr.Paren(expr = SynExpr.LibraryOnlyILAssembly _), _
+            | SynExpr.Paren(expr = SynExpr.LibraryOnlyStaticOptimization _), _
+            | SynExpr.Paren(expr = SynExpr.LibraryOnlyUnionCaseFieldGet _), _
+            | SynExpr.Paren(expr = SynExpr.LibraryOnlyUnionCaseFieldSet _), _ -> ValueNone
+
             // Parens are required around the body expresion of a binding
             // if the parenthesized expression would be invalid without its parentheses, e.g.,
             //

vsintegration/tests/FSharp.Editor.Tests/CodeFixes/RemoveUnnecessaryParenthesesTests.fs

@@ -668,6 +668,9 @@ let _ =
             """
             $"{3 + LanguagePrimitives.GenericZero<int> :N0}"
             """
+
+            // LibraryOnlyILAssembly
+            """(# "ldlen.multi 2 0" array : int #)""", """(# "ldlen.multi 2 0" array : int #)"""
         }
 
     [<Theory; MemberData(nameof exprs)>]