Add FSharpChecker.ParseFileNoCache (#7108)

* Add FSharpChecker.ParseFileNoCache

* Review feedback

src/fsharp/service/service.fs

@@ -423,6 +423,12 @@ type BackgroundCompiler(legacyReferenceResolver, projectCacheSize, keepAssemblyC
                 return res
         }
 
+    member bc.ParseFileNoCache(filename, sourceText, options, userOpName) =
+        async {
+            let parseErrors, parseTreeOpt, anyErrors = ParseAndCheckFile.parseFile(sourceText, filename, options, userOpName, false)
+            return FSharpParseFileResults(parseErrors, parseTreeOpt, anyErrors, options.SourceFiles)
+        }
+
     /// Fetch the parse information from the background compiler (which checks w.r.t. the FileSystem API)
     member __.GetBackgroundParseResultsForFileInProject(filename, options, userOpName) =
         reactor.EnqueueAndAwaitOpAsync(userOpName, "GetBackgroundParseResultsForFileInProject ", filename, fun ctok -> 
@@ -961,6 +967,11 @@ type FSharpChecker(legacyReferenceResolver,
         ic.CheckMaxMemoryReached()
         backgroundCompiler.ParseFile(filename, sourceText, options, userOpName)
 
+    member ic.ParseFileNoCache(filename, sourceText, options, ?userOpName) =
+        let userOpName = defaultArg userOpName "Unknown"
+        ic.CheckMaxMemoryReached()
+        backgroundCompiler.ParseFileNoCache(filename, sourceText, options, userOpName)
+
     member ic.ParseFileInProject(filename, source: string, options, ?userOpName: string) =
         let userOpName = defaultArg userOpName "Unknown"
         let parsingOptions, _ = ic.GetParsingOptionsFromProjectOptions(options)

src/fsharp/service/service.fsi

@@ -103,25 +103,32 @@ type public FSharpChecker =
     member MatchBraces: filename: string * source: string * options: FSharpProjectOptions * ?userOpName: string -> Async<(range * range)[]>
 
     /// <summary>
-    /// <para>Parse a source code file, returning a handle that can be used for obtaining navigation bar information
-    /// To get the full information, call 'CheckFileInProject' method on the result</para>
+    /// Parses a source code for a file and caches the results. Returns an AST that can be traversed for various features.
     /// </summary>
     ///
-    /// <param name="filename">The filename for the file.</param>
-    /// <param name="sourceText">The full source for the file.</param>
+    /// <param name="filename">The path for the file. The file name is used as a module name for implicit top level modules (e.g. in scripts).</param>
+    /// <param name="sourceText">The source to be parsed.</param>
     /// <param name="options">Parsing options for the project or script.</param>
     /// <param name="userOpName">An optional string used for tracing compiler operations associated with this request.</param>
     member ParseFile: filename: string * sourceText: ISourceText * options: FSharpParsingOptions * ?userOpName: string -> Async<FSharpParseFileResults>
 
     /// <summary>
-    /// <para>Parse a source code file, returning a handle that can be used for obtaining navigation bar information
-    /// To get the full information, call 'CheckFileInProject' method on the result</para>
-    /// <para>All files except the one being checked are read from the FileSystem API</para>
+    /// Parses a source code for a file. Returns an AST that can be traversed for various features.
     /// </summary>
     ///
-    /// <param name="filename">The filename for the file.</param>
-    /// <param name="source">The full source for the file.</param>
-    /// <param name="options">The options for the project or script, used to determine active --define conditionals and other options relevant to parsing.</param>
+    /// <param name="filename">The path for the file. The file name is also as a module name for implicit top level modules (e.g. in scripts).</param>
+    /// <param name="sourceText">The source to be parsed.</param>
+    /// <param name="options">Parsing options for the project or script.</param>
+    /// <param name="userOpName">An optional string used for tracing compiler operations associated with this request.</param>
+    member ParseFileNoCache: filename: string * sourceText: ISourceText * options: FSharpParsingOptions * ?userOpName: string -> Async<FSharpParseFileResults>
+
+    /// <summary>
+    /// Parses a source code for a file. Returns an AST that can be traversed for various features.
+    /// </summary>
+    ///
+    /// <param name="filename">The path for the file. The file name is also as a module name for implicit top level modules (e.g. in scripts).</param>
+    /// <param name="sourceText">The source to be parsed.</param>
+    /// <param name="options">Parsing options for the project or script.</param>
     /// <param name="userOpName">An optional string used for tracing compiler operations associated with this request.</param>
     [<Obsolete("Please call checker.ParseFile instead.  To do this, you must also pass FSharpParsingOptions instead of FSharpProjectOptions. If necessary generate FSharpParsingOptions from FSharpProjectOptions by calling checker.GetParsingOptionsFromProjectOptions(options)")>]
     member ParseFileInProject: filename: string * source: string * options: FSharpProjectOptions * ?userOpName: string -> Async<FSharpParseFileResults>