relax multiple load objection (#7613)

Author: KevinRansom

src/fsharp/CompileOps.fs

@@ -2572,17 +2572,13 @@ type TcConfig private (data: TcConfigBuilder, validate: bool) =
             let filename = ComputeMakePathAbsolute data.implicitIncludeDir r.Text
             if FileSystem.SafeExists filename then 
                 r, Some filename
-            else   
+            else
                 // If the file doesn't exist, let reference resolution logic report the error later...
                 defaultCoreLibraryReference, if Range.equals r.Range rangeStartup then Some(filename) else None
         match data.referencedDLLs |> List.filter (fun assemblyReference -> assemblyReference.SimpleAssemblyNameIs libraryName) with
-        | [r] -> nameOfDll r
-        | [] -> 
-            defaultCoreLibraryReference, None
-        | r :: _ -> 
-            // Recover by picking the first one.
-            errorR(Error(FSComp.SR.buildMultipleReferencesNotAllowed libraryName, rangeCmdArgs)) 
-            nameOfDll r
+        | [] -> defaultCoreLibraryReference, None
+        | [r]
+        | r :: _ -> nameOfDll r
 
     // Look for an explicit reference to mscorlib/netstandard.dll or System.Runtime.dll and use that to compute clrRoot and targetFrameworkVersion
     let primaryAssemblyReference, primaryAssemblyExplicitFilenameOpt = computeKnownDllReference(data.primaryAssembly.Name)

src/fsharp/FSComp.txt

@@ -43,7 +43,6 @@ buildProductNameCommunity,"F# Compiler for F# %s"
 212,buildInvalidFilename,"'%s' is not a valid filename"
 213,buildInvalidAssemblyName,"'%s' is not a valid assembly name"
 214,buildInvalidPrivacy,"Unrecognized privacy setting '%s' for managed resource, valid options are 'public' and 'private'"
-215,buildMultipleReferencesNotAllowed,"Multiple references to '%s.dll' are not permitted"
 218,buildCannotReadAssembly,"Unable to read assembly '%s'"
 220,buildAssemblyResolutionFailed,"Assembly resolution failure at or near this location"
 221,buildImplicitModuleIsNotLegalIdentifier,"The declarations in this file will be placed in an implicit module '%s' based on the file name '%s'. However this is not a valid F# identifier, so the contents will not be accessible from other files. Consider renaming the file or adding a 'module' or 'namespace' declaration at the top of the file."