diff --git a/.editorconfig b/.editorconfig
index 1caf766b86fe..cc2382db994b 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -170,6 +170,7 @@ file_header_template = Licensed to the .NET Foundation under one or more agreeme
 dotnet_code_quality.ca1802.api_surface = private, internal
 dotnet_code_quality.ca1822.api_surface = private, internal
 dotnet_code_quality.ca2208.api_surface = public
+dotnet_public_api_analyzer.require_api_files = true
 # Mark attributes with AttributeUsageAttribute
 dotnet_diagnostic.CA1018.severity = warning
 # Properties should not be write only
diff --git a/src/Cli/Microsoft.DotNet.FileBasedPrograms/FileLevelDirectiveHelpers.cs b/src/Cli/Microsoft.DotNet.FileBasedPrograms/FileLevelDirectiveHelpers.cs
index 1e4d853c08b2..99e7ba172924 100644
--- a/src/Cli/Microsoft.DotNet.FileBasedPrograms/FileLevelDirectiveHelpers.cs
+++ b/src/Cli/Microsoft.DotNet.FileBasedPrograms/FileLevelDirectiveHelpers.cs
@@ -36,7 +36,7 @@ public static SyntaxTokenParser CreateTokenizer(SourceText text)
     /// The latter is useful for <c>dotnet run file.cs</c> where if there are app directives after the first token,
     /// compiler reports <see cref="ErrorCode.ERR_PPIgnoredFollowsToken"/> anyway, so we speed up success scenarios by not parsing the whole file up front in the SDK CLI.
     /// </param>
-    public static ImmutableArray<CSharpDirective> FindDirectives(SourceFile sourceFile, bool reportAllErrors, ErrorReporter reportError)
+    public static ImmutableArray<CSharpDirective> FindDirectives(SourceFile sourceFile, bool reportAllErrors, ErrorReporter errorReporter)
     {
         var builder = ImmutableArray.CreateBuilder<CSharpDirective>();
         var tokenizer = CreateTokenizer(sourceFile.Text);
@@ -44,7 +44,7 @@ public static ImmutableArray<CSharpDirective> FindDirectives(SourceFile sourceFi
         var result = tokenizer.ParseLeadingTrivia();
         var triviaList = result.Token.LeadingTrivia;
 
-        FindLeadingDirectives(sourceFile, triviaList, reportError, builder);
+        FindLeadingDirectives(sourceFile, triviaList, errorReporter, builder);
 
         // In conversion mode, we want to report errors for any invalid directives in the rest of the file
         // so users don't end up with invalid directives in the converted project.
@@ -73,7 +73,7 @@ void ReportErrorFor(SyntaxTrivia trivia)
         {
             if (trivia.ContainsDiagnostics && trivia.IsKind(SyntaxKind.IgnoredDirectiveTrivia))
             {
-                reportError(sourceFile, trivia.Span, FileBasedProgramsResources.CannotConvertDirective);
+                errorReporter(sourceFile.Text, sourceFile.Path, trivia.Span, FileBasedProgramsResources.CannotConvertDirective);
             }
         }
 
@@ -86,7 +86,7 @@ void ReportErrorFor(SyntaxTrivia trivia)
     public static void FindLeadingDirectives(
         SourceFile sourceFile,
         SyntaxTriviaList triviaList,
-        ErrorReporter reportError,
+        ErrorReporter errorReporter,
         ImmutableArray<CSharpDirective>.Builder? builder)
     {
         var deduplicated = new Dictionary<CSharpDirective.Named, CSharpDirective.Named>(NamedDirectiveComparer.Instance);
@@ -144,7 +144,7 @@ public static void FindLeadingDirectives(
                         LeadingWhiteSpace = whiteSpace.Leading,
                         TrailingWhiteSpace = whiteSpace.Trailing,
                     },
-                    ReportError = reportError,
+                    ErrorReporter = errorReporter,
                     DirectiveKind = name,
                     DirectiveText = value,
                 };
@@ -152,7 +152,7 @@ public static void FindLeadingDirectives(
                 // Block quotes now so we can later support quoted values without a breaking change. https://github.com/dotnet/sdk/issues/49367
                 if (value.Contains('"'))
                 {
-                    reportError(sourceFile, context.Info.Span, FileBasedProgramsResources.QuoteInDirective);
+                    context.ReportError(FileBasedProgramsResources.QuoteInDirective);
                 }
 
                 if (CSharpDirective.Parse(context) is { } directive)
@@ -161,7 +161,7 @@ public static void FindLeadingDirectives(
                     if (deduplicated.TryGetValue(directive, out var existingDirective))
                     {
                         var typeAndName = $"#:{existingDirective.GetType().Name.ToLowerInvariant()} {existingDirective.Name}";
-                        reportError(sourceFile, directive.Info.Span, string.Format(FileBasedProgramsResources.DuplicateDirective, typeAndName));
+                        context.ReportError(directive.Info.Span, string.Format(FileBasedProgramsResources.DuplicateDirective, typeAndName));
                     }
                     else
                     {
@@ -230,16 +230,6 @@ public static SourceFile Load(string filePath)
         return new SourceFile(filePath, SourceText.From(stream, encoding: null));
     }
 
-    public SourceFile WithPath(string newPath)
-    {
-        return new SourceFile(newPath, Text);
-    }
-
-    public SourceFile WithText(SourceText newText)
-    {
-        return new SourceFile(Path, newText);
-    }
-
     public void Save()
     {
         using var stream = File.Open(Path, FileMode.Create, FileAccess.Write);
@@ -249,15 +239,9 @@ public void Save()
         Text.Write(writer);
     }
 
-    public FileLinePositionSpan GetFileLinePositionSpan(TextSpan span)
-    {
-        return new FileLinePositionSpan(Path, Text.Lines.GetLinePositionSpan(span));
-    }
-
     public string GetLocationString(TextSpan span)
     {
-        var positionSpan = GetFileLinePositionSpan(span);
-        return $"{positionSpan.Path}({positionSpan.StartLinePosition.Line + 1})";
+        return $"{Path}({Text.Lines.GetLinePositionSpan(span).Start.Line + 1})";
     }
 }
 
@@ -298,9 +282,15 @@ public readonly struct ParseInfo
     public readonly struct ParseContext
     {
         public required ParseInfo Info { get; init; }
-        public required ErrorReporter ReportError { get; init; }
+        public required ErrorReporter ErrorReporter { get; init; }
         public required string DirectiveKind { get; init; }
         public required string DirectiveText { get; init; }
+
+        public void ReportError(string message)
+            => ErrorReporter(Info.SourceFile.Text, Info.SourceFile.Path, Info.Span, message);
+
+        public void ReportError(TextSpan span, string message)
+            => ErrorReporter(Info.SourceFile.Text, Info.SourceFile.Path, span, message);
     }
 
     public static Named? Parse(in ParseContext context)
@@ -313,7 +303,7 @@ public readonly struct ParseContext
             case "project": return Project.Parse(context);
             case "include" or "exclude": return IncludeOrExclude.Parse(context);
             default:
-                context.ReportError(context.Info.SourceFile, context.Info.Span, string.Format(FileBasedProgramsResources.UnrecognizedDirective, context.DirectiveKind));
+                context.ReportError(string.Format(FileBasedProgramsResources.UnrecognizedDirective, context.DirectiveKind));
                 return null;
         }
     }
@@ -326,14 +316,14 @@ private static (string, string?)? ParseOptionalTwoParts(in ParseContext context,
         string directiveKind = context.DirectiveKind;
         if (firstPart.IsWhiteSpace())
         {
-            context.ReportError(context.Info.SourceFile, context.Info.Span, string.Format(FileBasedProgramsResources.MissingDirectiveName, directiveKind));
+            context.ReportError(string.Format(FileBasedProgramsResources.MissingDirectiveName, directiveKind));
             return null;
         }
 
         // If the name contains characters that resemble separators, report an error to avoid any confusion.
         if (Patterns.DisallowedNameCharacters.Match(context.DirectiveText, beginning: 0, length: firstPart.Length).Success)
         {
-            context.ReportError(context.Info.SourceFile, context.Info.Span, string.Format(FileBasedProgramsResources.InvalidDirectiveName, directiveKind, separator));
+            context.ReportError(string.Format(FileBasedProgramsResources.InvalidDirectiveName, directiveKind, separator));
             return null;
         }
 
@@ -409,7 +399,7 @@ public sealed class Property(in ParseInfo info) : Named(info)
 
             if (propertyValue is null)
             {
-                context.ReportError(context.Info.SourceFile, context.Info.Span, FileBasedProgramsResources.PropertyDirectiveMissingParts);
+                context.ReportError(FileBasedProgramsResources.PropertyDirectiveMissingParts);
                 return null;
             }
 
@@ -419,14 +409,14 @@ public sealed class Property(in ParseInfo info) : Named(info)
             }
             catch (XmlException ex)
             {
-                context.ReportError(context.Info.SourceFile, context.Info.Span, string.Format(FileBasedProgramsResources.PropertyDirectiveInvalidName, ex.Message), ex);
+                context.ReportError(string.Format(FileBasedProgramsResources.PropertyDirectiveInvalidName, ex.Message));
                 return null;
             }
 
             if (propertyName.Equals("RestoreUseStaticGraphEvaluation", StringComparison.OrdinalIgnoreCase) &&
                 MSBuildUtilities.ConvertStringToBool(propertyValue))
             {
-                context.ReportError(context.Info.SourceFile, context.Info.Span, FileBasedProgramsResources.StaticGraphRestoreNotSupported);
+                context.ReportError(FileBasedProgramsResources.StaticGraphRestoreNotSupported);
             }
 
             return new Property(context.Info)
@@ -498,8 +488,7 @@ public Project(in ParseInfo info, string name) : base(info)
             var directiveText = context.DirectiveText;
             if (directiveText.IsWhiteSpace())
             {
-                string directiveKind = context.DirectiveKind;
-                context.ReportError(context.Info.SourceFile, context.Info.Span, string.Format(FileBasedProgramsResources.MissingDirectiveName, directiveKind));
+                context.ReportError(string.Format(FileBasedProgramsResources.MissingDirectiveName, context.DirectiveKind));
                 return null;
             }
 
@@ -537,14 +526,15 @@ public Project WithName(string name, NameKind kind)
         /// <summary>
         /// If the directive points to a directory, returns a new directive pointing to the corresponding project file.
         /// </summary>
-        public Project EnsureProjectFilePath(ErrorReporter reportError)
+        public Project EnsureProjectFilePath(ErrorReporter errorReporter)
         {
             var resolvedName = Name;
+            var sourcePath = Info.SourceFile.Path;
 
             // If the path is a directory like '../lib', transform it to a project file path like '../lib/lib.csproj'.
             // Also normalize backslashes to forward slashes to ensure the directive works on all platforms.
-            var sourceDirectory = Path.GetDirectoryName(Info.SourceFile.Path)
-                ?? throw new InvalidOperationException($"Source file path '{Info.SourceFile.Path}' does not have a containing directory.");
+            var sourceDirectory = Path.GetDirectoryName(sourcePath)
+                ?? throw new InvalidOperationException($"Source file path '{sourcePath}' does not have a containing directory.");
 
             var resolvedProjectPath = Path.Combine(sourceDirectory, resolvedName.Replace('\\', '/'));
             if (Directory.Exists(resolvedProjectPath))
@@ -558,16 +548,18 @@ public Project EnsureProjectFilePath(ErrorReporter reportError)
                 }
                 else
                 {
-                    reportError(Info.SourceFile, Info.Span, string.Format(FileBasedProgramsResources.InvalidProjectDirective, error));
+                    ReportError(string.Format(FileBasedProgramsResources.InvalidProjectDirective, error));
                 }
             }
             else if (!File.Exists(resolvedProjectPath))
             {
-                reportError(Info.SourceFile, Info.Span,
-                    string.Format(FileBasedProgramsResources.InvalidProjectDirective, string.Format(FileBasedProgramsResources.CouldNotFindProjectOrDirectory, resolvedProjectPath)));
+                ReportError(string.Format(FileBasedProgramsResources.InvalidProjectDirective, string.Format(FileBasedProgramsResources.CouldNotFindProjectOrDirectory, resolvedProjectPath)));
             }
 
             return WithName(resolvedName, NameKind.ProjectFilePath);
+
+            void ReportError(string message)
+                => errorReporter(Info.SourceFile.Text, sourcePath, Info.Span, message);
         }
 
         public override string ToString() => $"#:project {Name}";
@@ -628,7 +620,7 @@ public sealed class IncludeOrExclude(in ParseInfo info) : Named(info)
             if (directiveText.IsWhiteSpace())
             {
                 string directiveKind = context.DirectiveKind;
-                context.ReportError(context.Info.SourceFile, context.Info.Span, string.Format(FileBasedProgramsResources.MissingDirectiveName, directiveKind));
+                context.ReportError(string.Format(FileBasedProgramsResources.MissingDirectiveName, directiveKind));
                 return null;
             }
 
@@ -659,7 +651,7 @@ public IncludeOrExclude WithDeterminedItemType(ErrorReporter reportError, Immuta
 
             if (itemType is null)
             {
-                reportError(Info.SourceFile, Info.Span,
+                reportError(Info.SourceFile.Text, Info.SourceFile.Path, Info.Span,
                     string.Format(FileBasedProgramsResources.IncludeOrExcludeDirectiveUnknownFileType,
                     $"#:{KindToString()}",
                     string.Join(", ", mapping.Select(static e => e.Extension))));
@@ -730,7 +722,7 @@ public string KindToMSBuildString()
         public static ImmutableArray<(string Extension, string ItemType)> ParseMapping(
             string value,
             SourceFile sourceFile,
-            ErrorReporter reportError)
+            ErrorReporter errorReporter)
         {
             var pairs = value.Split(';');
 
@@ -742,7 +734,7 @@ public string KindToMSBuildString()
 
                 if (parts.Length != 2)
                 {
-                    reportError(sourceFile, default, string.Format(FileBasedProgramsResources.InvalidIncludeExcludeMappingEntry, pair));
+                    ReportError(string.Format(FileBasedProgramsResources.InvalidIncludeExcludeMappingEntry, pair));
                     continue;
                 }
 
@@ -751,13 +743,13 @@ public string KindToMSBuildString()
 
                 if (extension is not ['.', _, ..])
                 {
-                    reportError(sourceFile, default, string.Format(FileBasedProgramsResources.InvalidIncludeExcludeMappingExtension, extension, pair));
+                    ReportError(string.Format(FileBasedProgramsResources.InvalidIncludeExcludeMappingExtension, extension, pair));
                     continue;
                 }
 
                 if (itemType.IsWhiteSpace())
                 {
-                    reportError(sourceFile, default, string.Format(FileBasedProgramsResources.InvalidIncludeExcludeMappingItemType, itemType, pair));
+                    ReportError(string.Format(FileBasedProgramsResources.InvalidIncludeExcludeMappingItemType, itemType, pair));
                     continue;
                 }
 
@@ -765,6 +757,9 @@ public string KindToMSBuildString()
             }
 
             return builder.DrainToImmutable();
+
+            void ReportError(string message)
+                => errorReporter(sourceFile.Text, sourceFile.Path, default, message);
         }
     }
 }
@@ -817,25 +812,25 @@ public readonly struct Position
     }
 }
 
-internal delegate void ErrorReporter(SourceFile sourceFile, TextSpan textSpan, string message, Exception? innerException = null);
+internal delegate void ErrorReporter(SourceText text, string path, TextSpan textSpan, string message, Exception? innerException = null);
 
 internal static partial class ErrorReporters
 {
     public static readonly ErrorReporter IgnoringReporter =
-        static (_, _, _, _) => { };
+        static (_, _, _, _, _) => { };
 
     public static ErrorReporter CreateCollectingReporter(out ImmutableArray<SimpleDiagnostic>.Builder builder)
     {
         var capturedBuilder = builder = ImmutableArray.CreateBuilder<SimpleDiagnostic>();
 
-        return (sourceFile, textSpan, message, _) =>
+        return (text, path, textSpan, message, _) =>
             capturedBuilder.Add(new SimpleDiagnostic
             {
                 Location = new SimpleDiagnostic.Position()
                 {
-                    Path = sourceFile.Path,
+                    Path = path,
                     TextSpan = textSpan,
-                    Span = sourceFile.GetFileLinePositionSpan(textSpan).Span
+                    Span = text.Lines.GetLinePositionSpan(textSpan)
                 },
                 Message = message
             });
diff --git a/src/Cli/Microsoft.DotNet.FileBasedPrograms/InternalAPI.Unshipped.txt b/src/Cli/Microsoft.DotNet.FileBasedPrograms/InternalAPI.Unshipped.txt
index 74c5d7f313bb..df17c8e67fc1 100644
--- a/src/Cli/Microsoft.DotNet.FileBasedPrograms/InternalAPI.Unshipped.txt
+++ b/src/Cli/Microsoft.DotNet.FileBasedPrograms/InternalAPI.Unshipped.txt
@@ -34,11 +34,13 @@ Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseContext.DirectiveKind.ge
 Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseContext.DirectiveKind.init -> void
 Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseContext.DirectiveText.get -> string!
 Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseContext.DirectiveText.init -> void
+Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseContext.ErrorReporter.get -> Microsoft.DotNet.FileBasedPrograms.ErrorReporter!
+Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseContext.ErrorReporter.init -> void
 Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseContext.Info.get -> Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseInfo
 Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseContext.Info.init -> void
 Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseContext.ParseContext() -> void
-Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseContext.ReportError.get -> Microsoft.DotNet.FileBasedPrograms.ErrorReporter!
-Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseContext.ReportError.init -> void
+Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseContext.ReportError(Microsoft.CodeAnalysis.Text.TextSpan span, string! message) -> void
+Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseContext.ReportError(string! message) -> void
 Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseContext.SourceFile.get -> Microsoft.DotNet.FileBasedPrograms.SourceFile
 Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseContext.SourceFile.init -> void
 Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseInfo
@@ -52,7 +54,7 @@ Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseInfo.Span.init -> void
 Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseInfo.TrailingWhiteSpace.get -> Microsoft.DotNet.FileBasedPrograms.WhiteSpaceInfo
 Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseInfo.TrailingWhiteSpace.init -> void
 Microsoft.DotNet.FileBasedPrograms.CSharpDirective.Project
-Microsoft.DotNet.FileBasedPrograms.CSharpDirective.Project.EnsureProjectFilePath(Microsoft.DotNet.FileBasedPrograms.ErrorReporter! reportError) -> Microsoft.DotNet.FileBasedPrograms.CSharpDirective.Project!
+Microsoft.DotNet.FileBasedPrograms.CSharpDirective.Project.EnsureProjectFilePath(Microsoft.DotNet.FileBasedPrograms.ErrorReporter! errorReporter) -> Microsoft.DotNet.FileBasedPrograms.CSharpDirective.Project!
 Microsoft.DotNet.FileBasedPrograms.CSharpDirective.Project.ExpandedName.get -> string?
 Microsoft.DotNet.FileBasedPrograms.CSharpDirective.Project.ExpandedName.init -> void
 Microsoft.DotNet.FileBasedPrograms.CSharpDirective.Project.NameKind
@@ -103,7 +105,6 @@ Microsoft.DotNet.FileBasedPrograms.SimpleDiagnostic.SimpleDiagnostic() -> void
 Microsoft.DotNet.FileBasedPrograms.SourceFile
 Microsoft.DotNet.FileBasedPrograms.SourceFile.Deconstruct(out string! Path, out Microsoft.CodeAnalysis.Text.SourceText! Text) -> void
 Microsoft.DotNet.FileBasedPrograms.SourceFile.Equals(Microsoft.DotNet.FileBasedPrograms.SourceFile other) -> bool
-Microsoft.DotNet.FileBasedPrograms.SourceFile.GetFileLinePositionSpan(Microsoft.CodeAnalysis.Text.TextSpan span) -> Microsoft.CodeAnalysis.FileLinePositionSpan
 Microsoft.DotNet.FileBasedPrograms.SourceFile.GetLocationString(Microsoft.CodeAnalysis.Text.TextSpan span) -> string!
 Microsoft.DotNet.FileBasedPrograms.SourceFile.Path.get -> string!
 Microsoft.DotNet.FileBasedPrograms.SourceFile.Path.init -> void
@@ -112,8 +113,6 @@ Microsoft.DotNet.FileBasedPrograms.SourceFile.SourceFile() -> void
 Microsoft.DotNet.FileBasedPrograms.SourceFile.SourceFile(string! Path, Microsoft.CodeAnalysis.Text.SourceText! Text) -> void
 Microsoft.DotNet.FileBasedPrograms.SourceFile.Text.get -> Microsoft.CodeAnalysis.Text.SourceText!
 Microsoft.DotNet.FileBasedPrograms.SourceFile.Text.init -> void
-Microsoft.DotNet.FileBasedPrograms.SourceFile.WithPath(string! newPath) -> Microsoft.DotNet.FileBasedPrograms.SourceFile
-Microsoft.DotNet.FileBasedPrograms.SourceFile.WithText(Microsoft.CodeAnalysis.Text.SourceText! newText) -> Microsoft.DotNet.FileBasedPrograms.SourceFile
 Microsoft.DotNet.FileBasedPrograms.WhiteSpaceInfo
 Microsoft.DotNet.FileBasedPrograms.WhiteSpaceInfo.LineBreaks -> int
 Microsoft.DotNet.FileBasedPrograms.WhiteSpaceInfo.TotalLength -> int
@@ -130,7 +129,7 @@ override Microsoft.DotNet.FileBasedPrograms.SourceFile.GetHashCode() -> int
 static Microsoft.DotNet.FileBasedPrograms.CSharpDirective.IncludeOrExclude.DefaultMapping.get -> System.Collections.Immutable.ImmutableArray<(string! Extension, string! ItemType)>
 static Microsoft.DotNet.FileBasedPrograms.CSharpDirective.IncludeOrExclude.DefaultMappingString.get -> string!
 static Microsoft.DotNet.FileBasedPrograms.CSharpDirective.IncludeOrExclude.Parse(in Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseContext context) -> Microsoft.DotNet.FileBasedPrograms.CSharpDirective.IncludeOrExclude?
-static Microsoft.DotNet.FileBasedPrograms.CSharpDirective.IncludeOrExclude.ParseMapping(string! value, Microsoft.DotNet.FileBasedPrograms.SourceFile sourceFile, Microsoft.DotNet.FileBasedPrograms.ErrorReporter! reportError) -> System.Collections.Immutable.ImmutableArray<(string! Extension, string! ItemType)>
+static Microsoft.DotNet.FileBasedPrograms.CSharpDirective.IncludeOrExclude.ParseMapping(string! value, Microsoft.DotNet.FileBasedPrograms.SourceFile sourceFile, Microsoft.DotNet.FileBasedPrograms.ErrorReporter! errorReporter) -> System.Collections.Immutable.ImmutableArray<(string! Extension, string! ItemType)>
 static Microsoft.DotNet.FileBasedPrograms.CSharpDirective.Package.Parse(in Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseContext context) -> Microsoft.DotNet.FileBasedPrograms.CSharpDirective.Package?
 static Microsoft.DotNet.FileBasedPrograms.CSharpDirective.Parse(in Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseContext context) -> Microsoft.DotNet.FileBasedPrograms.CSharpDirective.Named?
 static Microsoft.DotNet.FileBasedPrograms.CSharpDirective.Project.Parse(in Microsoft.DotNet.FileBasedPrograms.CSharpDirective.ParseContext context) -> Microsoft.DotNet.FileBasedPrograms.CSharpDirective.Project?
@@ -141,9 +140,8 @@ static Microsoft.DotNet.FileBasedPrograms.ExternalHelpers.CombineHashCodes(int v
 static Microsoft.DotNet.FileBasedPrograms.ExternalHelpers.GetRelativePath(string! relativeTo, string! path) -> string!
 static Microsoft.DotNet.FileBasedPrograms.ExternalHelpers.IsPathFullyQualified(string! path) -> bool
 static Microsoft.DotNet.FileBasedPrograms.FileLevelDirectiveHelpers.CreateTokenizer(Microsoft.CodeAnalysis.Text.SourceText! text) -> Microsoft.CodeAnalysis.CSharp.SyntaxTokenParser!
-static Microsoft.DotNet.FileBasedPrograms.FileLevelDirectiveHelpers.EvaluateDirectives(Microsoft.Build.Execution.ProjectInstance? project, System.Collections.Immutable.ImmutableArray<Microsoft.DotNet.FileBasedPrograms.CSharpDirective!> directives, Microsoft.DotNet.FileBasedPrograms.SourceFile sourceFile, Microsoft.DotNet.FileBasedPrograms.ErrorReporter! errorReporter) -> System.Collections.Immutable.ImmutableArray<Microsoft.DotNet.FileBasedPrograms.CSharpDirective!>
-static Microsoft.DotNet.FileBasedPrograms.FileLevelDirectiveHelpers.FindDirectives(Microsoft.DotNet.FileBasedPrograms.SourceFile sourceFile, bool reportAllErrors, Microsoft.DotNet.FileBasedPrograms.ErrorReporter! reportError) -> System.Collections.Immutable.ImmutableArray<Microsoft.DotNet.FileBasedPrograms.CSharpDirective!>
-static Microsoft.DotNet.FileBasedPrograms.FileLevelDirectiveHelpers.FindLeadingDirectives(Microsoft.DotNet.FileBasedPrograms.SourceFile sourceFile, Microsoft.CodeAnalysis.SyntaxTriviaList triviaList, Microsoft.DotNet.FileBasedPrograms.ErrorReporter! reportError, System.Collections.Immutable.ImmutableArray<Microsoft.DotNet.FileBasedPrograms.CSharpDirective!>.Builder? builder) -> void
+static Microsoft.DotNet.FileBasedPrograms.FileLevelDirectiveHelpers.FindDirectives(Microsoft.DotNet.FileBasedPrograms.SourceFile sourceFile, bool reportAllErrors, Microsoft.DotNet.FileBasedPrograms.ErrorReporter! errorReporter) -> System.Collections.Immutable.ImmutableArray<Microsoft.DotNet.FileBasedPrograms.CSharpDirective!>
+static Microsoft.DotNet.FileBasedPrograms.FileLevelDirectiveHelpers.FindLeadingDirectives(Microsoft.DotNet.FileBasedPrograms.SourceFile sourceFile, Microsoft.CodeAnalysis.SyntaxTriviaList triviaList, Microsoft.DotNet.FileBasedPrograms.ErrorReporter! errorReporter, System.Collections.Immutable.ImmutableArray<Microsoft.DotNet.FileBasedPrograms.CSharpDirective!>.Builder? builder) -> void
 static Microsoft.DotNet.FileBasedPrograms.MSBuildUtilities.ConvertStringToBool(string? parameterValue, bool defaultValue = false) -> bool
 static Microsoft.DotNet.FileBasedPrograms.Patterns.DisallowedNameCharacters.get -> System.Text.RegularExpressions.Regex!
 static Microsoft.DotNet.FileBasedPrograms.Patterns.EscapedCompilerOption.get -> System.Text.RegularExpressions.Regex!
@@ -154,6 +152,6 @@ static Microsoft.DotNet.FileBasedPrograms.SourceFile.operator ==(Microsoft.DotNe
 static Microsoft.DotNet.ProjectTools.ProjectLocator.TryGetProjectFileFromDirectory(string! projectDirectory, out string? projectFilePath, out string? error) -> bool
 static readonly Microsoft.DotNet.FileBasedPrograms.ErrorReporters.IgnoringReporter -> Microsoft.DotNet.FileBasedPrograms.ErrorReporter!
 static readonly Microsoft.DotNet.FileBasedPrograms.NamedDirectiveComparer.Instance -> Microsoft.DotNet.FileBasedPrograms.NamedDirectiveComparer!
-virtual Microsoft.DotNet.FileBasedPrograms.ErrorReporter.Invoke(Microsoft.DotNet.FileBasedPrograms.SourceFile sourceFile, Microsoft.CodeAnalysis.Text.TextSpan textSpan, string! message, System.Exception? innerException = null) -> void
+virtual Microsoft.DotNet.FileBasedPrograms.ErrorReporter.Invoke(Microsoft.CodeAnalysis.Text.SourceText! text, string! path, Microsoft.CodeAnalysis.Text.TextSpan textSpan, string! message, System.Exception? innerException = null) -> void
 ~override Microsoft.DotNet.FileBasedPrograms.SourceFile.Equals(object obj) -> bool
 ~override Microsoft.DotNet.FileBasedPrograms.SourceFile.ToString() -> string
\ No newline at end of file
diff --git a/src/Cli/dotnet/Commands/Project/Convert/ProjectConvertCommand.cs b/src/Cli/dotnet/Commands/Project/Convert/ProjectConvertCommand.cs
index 3a7256ef34d3..4cf768909127 100644
--- a/src/Cli/dotnet/Commands/Project/Convert/ProjectConvertCommand.cs
+++ b/src/Cli/dotnet/Commands/Project/Convert/ProjectConvertCommand.cs
@@ -43,7 +43,7 @@ public override int Execute()
         // Create a project instance for evaluation.
         var projectCollection = new ProjectCollection();
 
-        var builder = new VirtualProjectBuilder(file, VirtualProjectBuildingCommand.TargetFrameworkVersion);
+        var builder = new VirtualProjectBuilder(file, VirtualProjectBuildingCommand.TargetFramework);
 
         builder.CreateProjectInstance(
             projectCollection,
@@ -276,7 +276,7 @@ ImmutableArray<CSharpDirective> UpdateDirectives(ImmutableArray<CSharpDirective>
 
         IEnumerable<(string name, string value)> GetDefaultProperties()
         {
-            foreach (var (name, defaultValue) in VirtualProjectBuilder.GetDefaultProperties(VirtualProjectBuildingCommand.TargetFrameworkVersion))
+            foreach (var (name, defaultValue) in VirtualProjectBuilder.GetDefaultProperties(VirtualProjectBuildingCommand.TargetFramework))
             {
                 string projectValue = projectInstance.GetPropertyValue(name);
                 if (string.Equals(projectValue, defaultValue, StringComparison.OrdinalIgnoreCase))
diff --git a/src/Cli/dotnet/Commands/Run/Api/RunApiCommand.cs b/src/Cli/dotnet/Commands/Run/Api/RunApiCommand.cs
index 75a333573d09..8960eabd51cc 100644
--- a/src/Cli/dotnet/Commands/Run/Api/RunApiCommand.cs
+++ b/src/Cli/dotnet/Commands/Run/Api/RunApiCommand.cs
@@ -67,7 +67,7 @@ public override RunApiOutput Execute()
         {
             var builder = new VirtualProjectBuilder(
                 entryPointFileFullPath: EntryPointFileFullPath,
-                targetFrameworkVersion: VirtualProjectBuildingCommand.TargetFrameworkVersion,
+                targetFramework: VirtualProjectBuildingCommand.TargetFramework,
                 artifactsPath: ArtifactsPath);
 
             var errorReporter = ErrorReporters.CreateCollectingReporter(out var diagnostics);
@@ -83,7 +83,7 @@ public override RunApiOutput Execute()
             VirtualProjectBuilder.WriteProjectFile(
                 csprojWriter,
                 evaluatedDirectives,
-                VirtualProjectBuilder.GetDefaultProperties(VirtualProjectBuildingCommand.TargetFrameworkVersion),
+                VirtualProjectBuilder.GetDefaultProperties(VirtualProjectBuildingCommand.TargetFramework),
                 isVirtualProject: true,
                 entryPointFilePath: EntryPointFileFullPath,
                 artifactsPath: builder.ArtifactsPath);
diff --git a/src/Cli/dotnet/Commands/Run/FileBasedAppSourceEditor.cs b/src/Cli/dotnet/Commands/Run/FileBasedAppSourceEditor.cs
index 27ac23b56687..764aeec88f95 100644
--- a/src/Cli/dotnet/Commands/Run/FileBasedAppSourceEditor.cs
+++ b/src/Cli/dotnet/Commands/Run/FileBasedAppSourceEditor.cs
@@ -80,7 +80,7 @@ static string GetNewLine(SourceText text)
     public void Add(CSharpDirective directive)
     {
         var change = DetermineAddChange(directive);
-        SourceFile = SourceFile.WithText(SourceFile.Text.WithChanges([change]));
+        SourceFile = SourceFile with { Text = SourceFile.Text.WithChanges([change]) };
     }
 
     private TextChange DetermineAddChange(CSharpDirective directive)
@@ -231,7 +231,7 @@ public void Remove(CSharpDirective directive)
         var span = directive.Info.Span;
         var start = span.Start;
         var length = span.Length + DetermineTrailingLengthToRemove(directive);
-        SourceFile = SourceFile.WithText(SourceFile.Text.Replace(start: start, length: length, newText: string.Empty));
+        SourceFile = SourceFile with { Text = SourceFile.Text.Replace(start: start, length: length, newText: string.Empty) };
     }
 
     private static int DetermineTrailingLengthToRemove(CSharpDirective directive)
diff --git a/src/Cli/dotnet/Commands/Run/VirtualProjectBuildingCommand.cs b/src/Cli/dotnet/Commands/Run/VirtualProjectBuildingCommand.cs
index 25c047e8f53b..3cbd7b9bd1e8 100644
--- a/src/Cli/dotnet/Commands/Run/VirtualProjectBuildingCommand.cs
+++ b/src/Cli/dotnet/Commands/Run/VirtualProjectBuildingCommand.cs
@@ -83,6 +83,7 @@ internal sealed class VirtualProjectBuildingCommand : CommandBase
     ];
 
     public static string TargetFrameworkVersion => Product.TargetFrameworkVersion;
+    public static string TargetFramework => $"net{Product.TargetFrameworkVersion}";
 
     public bool NoRestore { get; init; }
 
@@ -151,7 +152,7 @@ public VirtualProjectBuildingCommand(
         }
         .AsReadOnly());
 
-        Builder = new VirtualProjectBuilder(entryPointFileFullPath, TargetFrameworkVersion, MSBuildArgs.GetResolvedTargets(), artifactsPath);
+        Builder = new VirtualProjectBuilder(entryPointFileFullPath, TargetFramework, MSBuildArgs.GetResolvedTargets(), artifactsPath);
     }
 
     public override int Execute()
@@ -1175,8 +1176,9 @@ public static void CreateTempSubdirectory(string path)
     }
 
     public static readonly ErrorReporter ThrowingReporter =
-        static (sourceFile, textSpan, message, innerException) => throw new GracefulException(
-            $"{sourceFile.GetLocationString(textSpan)}: {FileBasedProgramsResources.DirectiveError}: {message}",
+        static (text, path, textSpan, message, innerException) =>
+            throw new GracefulException(
+            $"{new SourceFile(path, text).GetLocationString(textSpan)}: {FileBasedProgramsResources.DirectiveError}: {message}",
             innerException);
 }
 
diff --git a/src/Microsoft.DotNet.ProjectTools/LaunchSettings/ExecutableLaunchProfile.cs b/src/Microsoft.DotNet.ProjectTools/LaunchSettings/ExecutableLaunchProfile.cs
index 67db2e0b93ce..e5b000fe50a8 100644
--- a/src/Microsoft.DotNet.ProjectTools/LaunchSettings/ExecutableLaunchProfile.cs
+++ b/src/Microsoft.DotNet.ProjectTools/LaunchSettings/ExecutableLaunchProfile.cs
@@ -5,7 +5,7 @@
 
 namespace Microsoft.DotNet.ProjectTools;
 
-public sealed class ExecutableLaunchProfile : LaunchProfile
+internal sealed class ExecutableLaunchProfile : LaunchProfile
 {
     public const string WorkingDirectoryPropertyName = "workingDirectory";
     public const string ExecutablePathPropertyName = "executablePath";
diff --git a/src/Microsoft.DotNet.ProjectTools/LaunchSettings/LaunchProfile.cs b/src/Microsoft.DotNet.ProjectTools/LaunchSettings/LaunchProfile.cs
index 87f6275e83b3..e994f6635cd7 100644
--- a/src/Microsoft.DotNet.ProjectTools/LaunchSettings/LaunchProfile.cs
+++ b/src/Microsoft.DotNet.ProjectTools/LaunchSettings/LaunchProfile.cs
@@ -6,7 +6,7 @@
 
 namespace Microsoft.DotNet.ProjectTools;
 
-public abstract class LaunchProfile
+internal abstract class LaunchProfile
 {
     [JsonIgnore]
     public string? LaunchProfileName { get; init; }
diff --git a/src/Microsoft.DotNet.ProjectTools/LaunchSettings/LaunchProfileParseResult.cs b/src/Microsoft.DotNet.ProjectTools/LaunchSettings/LaunchProfileParseResult.cs
index bf735a81cf0a..7bc2e979e3b9 100644
--- a/src/Microsoft.DotNet.ProjectTools/LaunchSettings/LaunchProfileParseResult.cs
+++ b/src/Microsoft.DotNet.ProjectTools/LaunchSettings/LaunchProfileParseResult.cs
@@ -5,7 +5,7 @@
 
 namespace Microsoft.DotNet.ProjectTools;
 
-public sealed class LaunchProfileParseResult
+internal sealed class LaunchProfileParseResult
 {
     public string? FailureReason { get; }
 
diff --git a/src/Microsoft.DotNet.ProjectTools/LaunchSettings/LaunchSettings.cs b/src/Microsoft.DotNet.ProjectTools/LaunchSettings/LaunchSettings.cs
index ae1c60161b27..e2f9725f18fd 100644
--- a/src/Microsoft.DotNet.ProjectTools/LaunchSettings/LaunchSettings.cs
+++ b/src/Microsoft.DotNet.ProjectTools/LaunchSettings/LaunchSettings.cs
@@ -18,12 +18,12 @@ public static class LaunchSettings
         { ExecutableLaunchProfileParser.CommandName, ExecutableLaunchProfileParser.Instance }
     };
 
-    public static IEnumerable<string> SupportedProfileTypes => s_providers.Keys;
+    internal static IEnumerable<string> SupportedProfileTypes => s_providers.Keys;
 
-    public static string GetPropertiesLaunchSettingsPath(string directoryPath, string propertiesDirectoryName)
+    internal static string GetPropertiesLaunchSettingsPath(string directoryPath, string propertiesDirectoryName)
         => Path.Combine(directoryPath, propertiesDirectoryName, "launchSettings.json");
 
-    public static string GetFlatLaunchSettingsPath(string directoryPath, string projectNameWithoutExtension)
+    internal static string GetFlatLaunchSettingsPath(string directoryPath, string projectNameWithoutExtension)
         => Path.Join(directoryPath, $"{projectNameWithoutExtension}.run.json");
 
     public static string? TryFindLaunchSettingsFile(string projectOrEntryPointFilePath, string? launchProfile, Action<string, bool> report)
@@ -71,7 +71,7 @@ public static string GetFlatLaunchSettingsPath(string directoryPath, string proj
         return null;
     }
 
-    public static LaunchProfileParseResult ReadProfileSettingsFromFile(string launchSettingsPath, string? profileName = null)
+    internal static LaunchProfileParseResult ReadProfileSettingsFromFile(string launchSettingsPath, string? profileName = null)
     {
         try
         {
diff --git a/src/Microsoft.DotNet.ProjectTools/LaunchSettings/ProjectLaunchProfile.cs b/src/Microsoft.DotNet.ProjectTools/LaunchSettings/ProjectLaunchProfile.cs
index a107dc29db84..d131b1f5c29d 100644
--- a/src/Microsoft.DotNet.ProjectTools/LaunchSettings/ProjectLaunchProfile.cs
+++ b/src/Microsoft.DotNet.ProjectTools/LaunchSettings/ProjectLaunchProfile.cs
@@ -5,7 +5,7 @@
 
 namespace Microsoft.DotNet.ProjectTools;
 
-public sealed class ProjectLaunchProfile : LaunchProfile
+internal sealed class ProjectLaunchProfile : LaunchProfile
 {
     [JsonPropertyName("launchBrowser")]
     public bool LaunchBrowser { get; init; }
diff --git a/src/Microsoft.DotNet.ProjectTools/Microsoft.DotNet.ProjectTools.csproj b/src/Microsoft.DotNet.ProjectTools/Microsoft.DotNet.ProjectTools.csproj
index 9de97043c331..ecea66d30440 100644
--- a/src/Microsoft.DotNet.ProjectTools/Microsoft.DotNet.ProjectTools.csproj
+++ b/src/Microsoft.DotNet.ProjectTools/Microsoft.DotNet.ProjectTools.csproj
@@ -12,14 +12,21 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.Build" />
+    <PackageReference Include="Microsoft.Build" ExcludeAssets="runtime" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp" />
+    <PackageReference Include="Microsoft.CodeAnalysis.PublicApiAnalyzers" Condition=" '$(DotNetBuildSourceOnly)' != 'true' ">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
   </ItemGroup>
 
   <ItemGroup>
     <InternalsVisibleTo Include="dotnet" />
+    <InternalsVisibleTo Include="dotnet-watch.Tests" />
     <InternalsVisibleTo Include="dotnet.Tests" />
-    <InternalsVisibleTo Include="Microsoft.DotNet.HotReload.Watch" />
+    <InternalsVisibleTo Include="Microsoft.NET.Build.Tests" Key="$(MicrosoftSharedPublicKey)" />
+    <InternalsVisibleTo Include="Microsoft.TemplateEngine.Cli" />
+    <InternalsVisibleTo Include="Microsoft.TemplateEngine.Cli.UnitTests" />
   </ItemGroup>
 
   <Import Project="..\Cli\Microsoft.DotNet.FileBasedPrograms\Microsoft.DotNet.FileBasedPrograms.projitems" Label="Shared" />
diff --git a/src/Microsoft.DotNet.ProjectTools/PublicAPI.Shipped.txt b/src/Microsoft.DotNet.ProjectTools/PublicAPI.Shipped.txt
new file mode 100644
index 000000000000..7dc5c58110bf
--- /dev/null
+++ b/src/Microsoft.DotNet.ProjectTools/PublicAPI.Shipped.txt
@@ -0,0 +1 @@
+#nullable enable
diff --git a/src/Microsoft.DotNet.ProjectTools/PublicAPI.Unshipped.txt b/src/Microsoft.DotNet.ProjectTools/PublicAPI.Unshipped.txt
new file mode 100644
index 000000000000..e22fc3a5db63
--- /dev/null
+++ b/src/Microsoft.DotNet.ProjectTools/PublicAPI.Unshipped.txt
@@ -0,0 +1,6 @@
+#nullable enable
+Microsoft.DotNet.ProjectTools.LaunchSettings
+Microsoft.DotNet.ProjectTools.VirtualProjectBuilder
+static Microsoft.DotNet.ProjectTools.LaunchSettings.TryFindLaunchSettingsFile(string! projectOrEntryPointFilePath, string? launchProfile, System.Action<string!, bool>! report) -> string?
+static Microsoft.DotNet.ProjectTools.VirtualProjectBuilder.GetVirtualProjectPath(string! entryPointFilePath) -> string!
+static Microsoft.DotNet.ProjectTools.VirtualProjectBuilder.IsValidEntryPointPath(string! entryPointFilePath) -> bool
diff --git a/src/Microsoft.DotNet.ProjectTools/Utilities/Sha256Hasher.cs b/src/Microsoft.DotNet.ProjectTools/Utilities/Sha256Hasher.cs
index 176173e776c5..7a7941e02a39 100644
--- a/src/Microsoft.DotNet.ProjectTools/Utilities/Sha256Hasher.cs
+++ b/src/Microsoft.DotNet.ProjectTools/Utilities/Sha256Hasher.cs
@@ -5,7 +5,7 @@
 
 namespace Microsoft.DotNet.Utilities;
 
-public static class Sha256Hasher
+internal static class Sha256Hasher
 {
     /// <summary>
     /// The hashed mac address needs to be the same hashed value as produced by the other distinct sources given the same input. (e.g. VsCode)
diff --git a/src/Microsoft.DotNet.ProjectTools/VirtualProjectBuilder.cs b/src/Microsoft.DotNet.ProjectTools/VirtualProjectBuilder.cs
index 146947972766..0245bef68abc 100644
--- a/src/Microsoft.DotNet.ProjectTools/VirtualProjectBuilder.cs
+++ b/src/Microsoft.DotNet.ProjectTools/VirtualProjectBuilder.cs
@@ -15,15 +15,15 @@
 
 namespace Microsoft.DotNet.ProjectTools;
 
-internal sealed class VirtualProjectBuilder
+public sealed class VirtualProjectBuilder
 {
     private readonly IEnumerable<(string name, string value)> _defaultProperties;
 
     private (ImmutableArray<CSharpDirective> Original, ImmutableArray<CSharpDirective> Evaluated)? _evaluatedDirectives;
 
-    public string EntryPointFileFullPath { get; }
+    internal string EntryPointFileFullPath { get; }
 
-    public SourceFile EntryPointSourceFile
+    internal SourceFile EntryPointSourceFile
     {
         get
         {
@@ -36,14 +36,14 @@ public SourceFile EntryPointSourceFile
         }
     }
 
-    public string ArtifactsPath
+    internal string ArtifactsPath
         => field ??= GetArtifactsPath(EntryPointFileFullPath);
 
-    public string[]? RequestedTargets { get; }
+    internal string[]? RequestedTargets { get; }
 
-    public VirtualProjectBuilder(
+    internal VirtualProjectBuilder(
         string entryPointFileFullPath,
-        string targetFrameworkVersion,
+        string targetFramework,
         string[]? requestedTargets = null,
         string? artifactsPath = null,
         SourceText? sourceText = null)
@@ -53,7 +53,7 @@ public VirtualProjectBuilder(
         EntryPointFileFullPath = entryPointFileFullPath;
         RequestedTargets = requestedTargets;
         ArtifactsPath = artifactsPath;
-        _defaultProperties = GetDefaultProperties(targetFrameworkVersion);
+        _defaultProperties = GetDefaultProperties(targetFramework);
 
         if (sourceText != null)
         {
@@ -64,17 +64,17 @@ public VirtualProjectBuilder(
     /// <remarks>
     /// Kept in sync with the default <c>dotnet new console</c> project file (enforced by <c>DotnetProjectConvertTests.SameAsTemplate</c>).
     /// </remarks>
-    public static IEnumerable<(string name, string value)> GetDefaultProperties(string targetFrameworkVersion) =>
+    internal static IEnumerable<(string name, string value)> GetDefaultProperties(string targetFramework) =>
     [
         ("OutputType", "Exe"),
-        ("TargetFramework", $"net{targetFrameworkVersion}"),
+        ("TargetFramework", targetFramework),
         ("ImplicitUsings", "enable"),
         ("Nullable", "enable"),
         ("PublishAot", "true"),
         ("PackAsTool", "true"),
     ];
 
-    public static string GetArtifactsPath(string entryPointFileFullPath)
+    internal static string GetArtifactsPath(string entryPointFileFullPath)
     {
         // Include entry point file name so the directory name is not completely opaque.
         string fileName = Path.GetFileNameWithoutExtension(entryPointFileFullPath);
@@ -84,10 +84,13 @@ public static string GetArtifactsPath(string entryPointFileFullPath)
         return GetTempSubpath(directoryName);
     }
 
+    public static string GetVirtualProjectPath(string entryPointFilePath)
+        => Path.ChangeExtension(entryPointFilePath, ".csproj");
+
     /// <summary>
     /// Obtains a temporary subdirectory for file-based app artifacts, e.g., <c>/tmp/dotnet/runfile/</c>.
     /// </summary>
-    public static string GetTempSubdirectory()
+    internal static string GetTempSubdirectory()
     {
         // We want a location where permissions are expected to be restricted to the current user.
         string directory = RuntimeInformation.IsOSPlatform(OSPlatform.Windows)
@@ -105,7 +108,7 @@ public static string GetTempSubdirectory()
     /// <summary>
     /// Obtains a specific temporary path in a subdirectory for file-based app artifacts, e.g., <c>/tmp/dotnet/runfile/{name}</c>.
     /// </summary>
-    public static string GetTempSubpath(string name)
+    internal static string GetTempSubpath(string name)
     {
         return Path.Join(GetTempSubdirectory(), name);
     }
@@ -198,7 +201,7 @@ private ImmutableArray<CSharpDirective> EvaluateDirectives(
         return builder.DrainToImmutable();
     }
 
-    public ImmutableArray<(string Extension, string ItemType)> GetItemMapping(ProjectInstance project, ErrorReporter reportError)
+    internal ImmutableArray<(string Extension, string ItemType)> GetItemMapping(ProjectInstance project, ErrorReporter reportError)
     {
         return MSBuildUtilities.ConvertStringToBool(project.GetPropertyValue(CSharpDirective.IncludeOrExclude.ExperimentalFileBasedProgramEnableItemMapping))
             ? CSharpDirective.IncludeOrExclude.ParseMapping(
@@ -208,7 +211,7 @@ private ImmutableArray<CSharpDirective> EvaluateDirectives(
             : CSharpDirective.IncludeOrExclude.DefaultMapping;
     }
 
-    public void CreateProjectInstance(
+    internal void CreateProjectInstance(
         ProjectCollection projectCollection,
         ErrorReporter reportError,
         out ProjectInstance project,
@@ -295,7 +298,7 @@ bool TryGetNextFileToProcess()
             {
                 if (!File.Exists(filePath))
                 {
-                    reportError(EntryPointSourceFile, default, string.Format(Resources.IncludedFileNotFound, filePath));
+                    reportError(EntryPointSourceFile.Text, EntryPointSourceFile.Path, default, string.Format(Resources.IncludedFileNotFound, filePath));
                     continue;
                 }
 
@@ -398,14 +401,15 @@ void CheckFlagEnabled(ref bool? flag, string flagName, CSharpDirective directive
             if (!value)
             {
                 reportError(
-                    directive.Info.SourceFile,
+                    directive.Info.SourceFile.Text,
+                    directive.Info.SourceFile.Path,
                     directive.Info.Span,
                     string.Format(Resources.ExperimentalFeatureDisabled, flagName));
             }
         }
     }
 
-    public static void WriteProjectFile(
+    internal static void WriteProjectFile(
         TextWriter writer,
         ImmutableArray<CSharpDirective> directives,
         IEnumerable<(string name, string value)> defaultProperties,
@@ -754,7 +758,7 @@ static void WriteImport(TextWriter writer, string project, CSharpDirective.Sdk s
         }
     }
 
-    public static SourceFile RemoveDirectivesFromFile(ImmutableArray<CSharpDirective> directives, SourceFile sourceFile)
+    internal static SourceFile RemoveDirectivesFromFile(ImmutableArray<CSharpDirective> directives, SourceFile sourceFile)
     {
         if (directives.Length == 0)
         {
@@ -779,12 +783,12 @@ public static SourceFile RemoveDirectivesFromFile(ImmutableArray<CSharpDirective
             }
         }
 
-        return sourceFile.WithText(text);
+        return sourceFile with { Text = text };
     }
 
-    public static void RemoveDirectivesFromFile(ImmutableArray<CSharpDirective> directives, SourceFile sourceFile, string targetFilePath)
+    internal static void RemoveDirectivesFromFile(ImmutableArray<CSharpDirective> directives, SourceFile sourceFile, string targetFilePath)
     {
         var modifiedFile = RemoveDirectivesFromFile(directives, sourceFile);
-        modifiedFile.WithPath(targetFilePath).Save();
+        (modifiedFile with { Path = targetFilePath }).Save();
     }
 }
diff --git a/test/dotnet.Tests/CommandTests/Project/Convert/DotnetProjectConvertTests.cs b/test/dotnet.Tests/CommandTests/Project/Convert/DotnetProjectConvertTests.cs
index 87a1e4100431..b379f8eee8bb 100644
--- a/test/dotnet.Tests/CommandTests/Project/Convert/DotnetProjectConvertTests.cs
+++ b/test/dotnet.Tests/CommandTests/Project/Convert/DotnetProjectConvertTests.cs
@@ -1937,7 +1937,7 @@ private static void Convert(
     {
         var builder = new VirtualProjectBuilder(
             entryPointFileFullPath: filePath,
-            targetFrameworkVersion: VirtualProjectBuildingCommand.TargetFrameworkVersion,
+            targetFramework: VirtualProjectBuildingCommand.TargetFramework,
             sourceText: SourceText.From(inputCSharp, Encoding.UTF8));
 
         var errorReporter = ErrorReporters.CreateCollectingReporter(out actualDiagnostics);
@@ -1963,7 +1963,7 @@ private static void Convert(
         VirtualProjectBuilder.WriteProjectFile(
             projectWriter,
             directives,
-            VirtualProjectBuilder.GetDefaultProperties(VirtualProjectBuildingCommand.TargetFrameworkVersion),
+            VirtualProjectBuilder.GetDefaultProperties(VirtualProjectBuildingCommand.TargetFramework),
             isVirtualProject: false);
 
         actualProject = projectWriter.ToString();
diff --git a/test/dotnet.Tests/CommandTests/Run/RunFileTests.cs b/test/dotnet.Tests/CommandTests/Run/RunFileTests.cs
index 732de1dde6b2..c908a7142cf2 100644
--- a/test/dotnet.Tests/CommandTests/Run/RunFileTests.cs
+++ b/test/dotnet.Tests/CommandTests/Run/RunFileTests.cs
@@ -5,6 +5,7 @@
 using System.Runtime.Versioning;
 using System.Text.Json;
 using Basic.CompilerLog.Util;
+using Microsoft.Build.Evaluation;
 using Microsoft.Build.Framework;
 using Microsoft.Build.Logging.StructuredLogger;
 using Microsoft.CodeAnalysis;
@@ -3808,7 +3809,7 @@ public void IncludeDirective_CustomMapping_Api()
 
         var builder = new VirtualProjectBuilder(
             entryPointFileFullPath: programPath,
-            targetFrameworkVersion: VirtualProjectBuildingCommand.TargetFrameworkVersion,
+            targetFramework: VirtualProjectBuildingCommand.TargetFramework,
             sourceText: SourceText.From(code, Encoding.UTF8));
 
         var directives = FileLevelDirectiveHelpers.FindDirectives(
@@ -5513,7 +5514,7 @@ public void Api()
             #!/program
             #:sdk Microsoft.NET.Sdk
             #:sdk Aspire.AppHost.Sdk@9.1.0
-            #:property TargetFramework=net11.0
+            #:property TargetFramework=net5.0
             #:package System.CommandLine@2.0.0-beta4.22272.1
             #:property LangVersion=preview
             Console.WriteLine();
@@ -5554,7 +5555,7 @@ public void Api()
                       <Import Project="Sdk.props" Sdk="Aspire.AppHost.Sdk" Version="9.1.0" />
 
                       <PropertyGroup>
-                        <TargetFramework>net11.0</TargetFramework>
+                        <TargetFramework>net5.0</TargetFramework>
                         <LangVersion>preview</LangVersion>
                         <RestoreUseStaticGraphEvaluation>false</RestoreUseStaticGraphEvaluation>
                         <Features>$(Features);FileBasedProgram</Features>