Make checkSuffix function case insensitive (#13004)

* Make checkSuffix case insensitive

* Remove redundant hasSuffixCaseInsensitive function. It does the same thing as checkSuffix

src/fsharp/CompilerConfig.fs

@@ -720,7 +720,7 @@ type TcConfigBuilder =
         use unwindBuildPhase = PushThreadBuildPhaseUntilUnwind BuildPhase.Parameter
         if sourceFiles = [] then errorR(Error(FSComp.SR.buildNoInputsSpecified(), rangeCmdArgs))
         let ext() = match tcConfigB.target with CompilerTarget.Dll -> ".dll" | CompilerTarget.Module -> ".netmodule" | CompilerTarget.ConsoleExe | CompilerTarget.WinExe -> ".exe"
-        let implFiles = sourceFiles |> List.filter (fun lower -> List.exists (FileSystemUtils.checkSuffix (String.lowercase lower)) FSharpImplFileSuffixes)
+        let implFiles = sourceFiles |> List.filter (fun fileName -> List.exists (FileSystemUtils.checkSuffix fileName) FSharpImplFileSuffixes)
         let outfile =
             match tcConfigB.outputFile, List.rev implFiles with
             | None, [] -> "out" + ext()
@@ -1168,8 +1168,7 @@ type TcConfig private (data: TcConfigBuilder, validate: bool) =
 
     member tcConfig.ComputeLightSyntaxInitialStatus filename =
         use unwindBuildPhase = PushThreadBuildPhaseUntilUnwind BuildPhase.Parameter
-        let lower = String.lowercase filename
-        let lightOnByDefault = List.exists (FileSystemUtils.checkSuffix lower) FSharpLightSyntaxFileSuffixes
+        let lightOnByDefault = List.exists (FileSystemUtils.checkSuffix filename) FSharpLightSyntaxFileSuffixes
         if lightOnByDefault then (tcConfig.light <> Some false) else (tcConfig.light = Some true )
 
     member tcConfig.GetAvailableLoadedSources() =

src/fsharp/ParseAndCheckInputs.fs

@@ -43,8 +43,7 @@ let CanonicalizeFilename filename =
     String.capitalize (try FileSystemUtils.chopExtension basic with _ -> basic)
 
 let IsScript filename =
-    let lower = String.lowercase filename
-    FSharpScriptFileSuffixes |> List.exists (FileSystemUtils.checkSuffix lower)
+    FSharpScriptFileSuffixes |> List.exists (FileSystemUtils.checkSuffix filename)
 
 // Give a unique name to the different kinds of inputs. Used to correlate signature and implementation files
 //   QualFileNameOfModuleName - files with a single module declaration or an anonymous module
@@ -115,8 +114,7 @@ let PostParseModuleImpl (_i, defaultNamespace, isLastCompiland, filename, impl)
 
     | ParsedImplFileFragment.AnonModule (defs, m)->
         let isLast, isExe = isLastCompiland
-        let lower = String.lowercase filename
-        if not (isLast && isExe) && not (doNotRequireNamespaceOrModuleSuffixes |> List.exists (FileSystemUtils.checkSuffix lower)) then
+        if not (isLast && isExe) && not (doNotRequireNamespaceOrModuleSuffixes |> List.exists (FileSystemUtils.checkSuffix filename)) then
             match defs with
             | SynModuleDecl.NestedModule _ :: _ -> errorR(Error(FSComp.SR.noEqualSignAfterModule(), trimRangeToLine m))
             | _ -> errorR(Error(FSComp.SR.buildMultiFileRequiresNamespaceOrModule(), trimRangeToLine m))
@@ -145,8 +143,7 @@ let PostParseModuleSpec (_i, defaultNamespace, isLastCompiland, filename, intf)
 
     | ParsedSigFileFragment.AnonModule (defs, m) ->
         let isLast, isExe = isLastCompiland
-        let lower = String.lowercase filename
-        if not (isLast && isExe) && not (doNotRequireNamespaceOrModuleSuffixes |> List.exists (FileSystemUtils.checkSuffix lower)) then
+        if not (isLast && isExe) && not (doNotRequireNamespaceOrModuleSuffixes |> List.exists (FileSystemUtils.checkSuffix filename)) then
             match defs with
             | SynModuleSigDecl.NestedModule _ :: _ -> errorR(Error(FSComp.SR.noEqualSignAfterModule(), m))
             | _ -> errorR(Error(FSComp.SR.buildMultiFileRequiresNamespaceOrModule(), m))
@@ -273,7 +270,6 @@ let ParseInput (lexer, diagnosticOptions:FSharpDiagnosticOptions, errorLogger: E
     //        # 1000 "Line01.fs"
     //    then it also asserts. But these are edge cases that can be fixed later, e.g. in bug 4651.
     //System.Diagnostics.Debug.Assert(System.IO.Path.IsPathRooted filename, sprintf "should be absolute: '%s'" filename)
-    let lower = String.lowercase filename
 
     // Delay sending errors and warnings until after the file is parsed. This gives us a chance to scrape the
     // #nowarn declarations for the file
@@ -284,18 +280,18 @@ let ParseInput (lexer, diagnosticOptions:FSharpDiagnosticOptions, errorLogger: E
     let mutable scopedPragmas = []
     try
         let input =
-            if mlCompatSuffixes |> List.exists (FileSystemUtils.checkSuffix lower) then
+            if mlCompatSuffixes |> List.exists (FileSystemUtils.checkSuffix filename) then
                 if lexbuf.SupportsFeature LanguageFeature.MLCompatRevisions then
                     errorR(Error(FSComp.SR.buildInvalidSourceFileExtensionML filename, rangeStartup))
                 else
                     mlCompatWarning (FSComp.SR.buildCompilingExtensionIsForML()) rangeStartup
 
             // Call the appropriate parser - for signature files or implementation files
-            if FSharpImplFileSuffixes |> List.exists (FileSystemUtils.checkSuffix lower) then
+            if FSharpImplFileSuffixes |> List.exists (FileSystemUtils.checkSuffix filename) then
                 let impl = Parser.implementationFile lexer lexbuf
                 let tripleSlashComments = LexbufLocalXmlDocStore.ReportInvalidXmlDocPositions(lexbuf)
                 PostParseModuleImpls (defaultNamespace, filename, isLastCompiland, impl, lexbuf, tripleSlashComments)
-            elif FSharpSigFileSuffixes |> List.exists (FileSystemUtils.checkSuffix lower) then
+            elif FSharpSigFileSuffixes |> List.exists (FileSystemUtils.checkSuffix filename) then
                 let intfs = Parser.signatureFile lexer lexbuf
                 let tripleSlashComments =  LexbufLocalXmlDocStore.ReportInvalidXmlDocPositions(lexbuf)
                 PostParseModuleSpecs (defaultNamespace, filename, isLastCompiland, intfs, lexbuf, tripleSlashComments)
@@ -350,8 +346,7 @@ let ReportParsingStatistics res =
         printfn "parsing yielded %d definitions" (List.collect flattenModImpl impls).Length
 
 let EmptyParsedInput(filename, isLastCompiland) =
-    let lower = String.lowercase filename
-    if FSharpSigFileSuffixes |> List.exists (FileSystemUtils.checkSuffix lower) then
+    if FSharpSigFileSuffixes |> List.exists (FileSystemUtils.checkSuffix filename) then
         ParsedInput.SigFile(
             ParsedSigFileInput(
                 filename,
@@ -432,9 +427,7 @@ let ParseOneInputLexbuf (tcConfig: TcConfig, lexResourceManager, lexbuf, filenam
 let ValidSuffixes = FSharpSigFileSuffixes@FSharpImplFileSuffixes
 
 let checkInputFile (tcConfig: TcConfig) filename =
-    let lower = String.lowercase filename
-
-    if List.exists (FileSystemUtils.checkSuffix lower) ValidSuffixes then
+    if List.exists (FileSystemUtils.checkSuffix filename) ValidSuffixes then
         if not(FileSystem.FileExistsShim filename) then
             error(Error(FSComp.SR.buildCouldNotFindSourceFile filename, rangeStartup))
     else

src/fsharp/XmlDocFileWriter.fs

@@ -80,7 +80,7 @@ module XmlDocWriter =
         doModuleSig None generatedCcu.Contents
 
     let WriteXmlDocFile (g, assemblyName, generatedCcu: CcuThunk, xmlfile) =
-        if not (FileSystemUtils.hasSuffixCaseInsensitive "xml" xmlfile ) then
+        if not (FileSystemUtils.checkSuffix xmlfile "xml" ) then
             error(Error(FSComp.SR.docfileNoXmlSuffix(), Range.rangeStartup))
 
         let mutable members = []

src/fsharp/absil/illib.fs

@@ -77,6 +77,9 @@ module internal PervasiveAutoOpens =
         member inline x.EndsWithOrdinal value =
             x.EndsWith(value, StringComparison.Ordinal)
 
+        member inline x.EndsWithOrdinalIgnoreCase value =
+            x.EndsWith(value, StringComparison.OrdinalIgnoreCase)
+
     /// Get an initialization hole 
     let getHole (r: _ ref) = match r.Value with None -> failwith "getHole" | Some x -> x
 

src/fsharp/absil/illib.fsi

@@ -61,6 +61,8 @@ module internal PervasiveAutoOpens =
 
         member inline EndsWithOrdinal: value:string -> bool
 
+        member inline EndsWithOrdinalIgnoreCase: value:string -> bool
+
     type Async with
         /// Runs the computation synchronously, always starting on the current thread.
         static member RunImmediate: computation: Async<'T> * ?cancellationToken: CancellationToken -> 'T

src/fsharp/fsc.fs

@@ -265,8 +265,7 @@ let SetProcessThreadLocals tcConfigB =
 let ProcessCommandLineFlags (tcConfigB: TcConfigBuilder, lcidFromCodePage, argv) =
     let mutable inputFilesRef = []
     let collect name =
-        let lower = String.lowercase name
-        if List.exists (FileSystemUtils.checkSuffix lower) [".resx"]  then
+        if List.exists (FileSystemUtils.checkSuffix name) [".resx"]  then
             error(Error(FSComp.SR.fscResxSourceFileDeprecated name, rangeStartup))
         else
             inputFilesRef <- name :: inputFilesRef

src/fsharp/service/FSharpCheckerResults.fs

@@ -1643,8 +1643,7 @@ module internal ParseAndCheckFile =
         member _.AnyErrors = errorCount > 0
 
     let getLightSyntaxStatus fileName options =
-        let lower = String.lowercase fileName
-        let lightOnByDefault = List.exists (FileSystemUtils.checkSuffix lower) FSharpLightSyntaxFileSuffixes
+        let lightOnByDefault = List.exists (FileSystemUtils.checkSuffix fileName) FSharpLightSyntaxFileSuffixes
         let lightStatus = if lightOnByDefault then (options.LightSyntax <> Some false) else (options.LightSyntax = Some true)
         LightSyntaxStatus(lightStatus, true)
 

src/fsharp/service/IncrementalBuild.fs

@@ -115,8 +115,7 @@ module IncrementalBuildSyntaxTree =
 
             try
                 IncrementalBuilderEventTesting.MRU.Add(IncrementalBuilderEventTesting.IBEParsed filename)
-                let lower = String.lowercase filename
-                let canSkip = sigNameOpt.IsSome && FSharpImplFileSuffixes |> List.exists (FileSystemUtils.checkSuffix lower)
+                let canSkip = sigNameOpt.IsSome && FSharpImplFileSuffixes |> List.exists (FileSystemUtils.checkSuffix filename)
                 let input =
                     if canSkip then
                         ParsedInput.ImplFile(

src/fsharp/utils/FileSystem.fs

@@ -386,7 +386,7 @@ module internal FileSystemUtils =
             for c in path do
                 if chars.Contains c then raise(IllegalFileNameChar(path, c)))
 
-    let checkSuffix (x:string) (y:string) = x.EndsWithOrdinal(y)
+    let checkSuffix (x:string) (y:string) = x.EndsWithOrdinalIgnoreCase(y)
 
     let hasExtensionWithValidate (validate:bool) (s:string) =
         if validate then (checkPathForIllegalChars s)
@@ -416,10 +416,7 @@ module internal FileSystemUtils =
     let trimQuotes (s:string) =
         s.Trim( [|' '; '\"'|] )
 
-    let hasSuffixCaseInsensitive suffix filename = (* case-insensitive *)
-        checkSuffix (String.lowercase filename) (String.lowercase suffix)
-
-    let isDll file = hasSuffixCaseInsensitive ".dll" file
+    let isDll file = checkSuffix file ".dll"
 
 [<Experimental("This FCS API/Type is experimental and subject to change.")>]
 type IAssemblyLoader =

src/fsharp/utils/FileSystem.fsi

@@ -106,6 +106,7 @@ module internal FileSystemUtils =
 
     /// <c>checkSuffix f s</c> returns True if filename "f" ends in suffix "s",
     /// e.g. checkSuffix "abc.fs" ".fs" returns true.
+    /// Disregards casing, e.g. checkSuffix "abc.Fs" ".fs" returns true.
     val checkSuffix: string -> string -> bool
 
     /// <c>chopExtension f</c> removes the extension from the given
@@ -125,9 +126,6 @@ module internal FileSystemUtils =
     /// Trim the quotes and spaces from either end of a string
     val trimQuotes: string -> string
 
-    /// Checks whether filename ends in suffix, ignoring case.
-    val hasSuffixCaseInsensitive: string -> string -> bool
-
     /// Checks whether file is dll (ends in .dll)
     val isDll: string -> bool