C#: Address review comments.

Author: michaelnebel

csharp/extractor/Semmle.Extraction.CSharp/Entities/PreprocessorDirectives/LineDirective.cs

@@ -8,22 +8,18 @@ namespace Semmle.Extraction.CSharp.Entities
     internal class LineDirective : LineOrSpanDirective<LineDirectiveTriviaSyntax>
     {
         private LineDirective(Context cx, LineDirectiveTriviaSyntax trivia)
-            : base(cx, trivia)
-        {
-        }
-
-        protected override void PopulatePreprocessor(TextWriter trapFile)
-        {
-            var type = Symbol.Line.Kind() switch
+            : base(cx, trivia, trivia.Line.Kind() switch
             {
                 SyntaxKind.DefaultKeyword => LineDirectiveKind.Default,
                 SyntaxKind.HiddenKeyword => LineDirectiveKind.Hidden,
                 SyntaxKind.NumericLiteralToken => LineDirectiveKind.Numeric,
-                _ => throw new InternalError(Symbol, "Unhandled line token kind")
-            };
-
-            trapFile.directive_lines(this, type);
+                _ => throw new InternalError(trivia, "Unhandled line token kind")
+            })
+        {
+        }
 
+        protected override void PopulatePreprocessor(TextWriter trapFile)
+        {
             if (Symbol.Line.IsKind(SyntaxKind.NumericLiteralToken))
             {
                 var value = (int)Symbol.Line.Value!;

csharp/extractor/Semmle.Extraction.CSharp/Entities/PreprocessorDirectives/LineOrSpanDirective.cs

@@ -15,13 +15,18 @@ internal enum LineDirectiveKind
 
     internal abstract class LineOrSpanDirective<T> : PreprocessorDirective<T> where T : LineOrSpanDirectiveTriviaSyntax
     {
-        protected LineOrSpanDirective(Context cx, T trivia)
+        private readonly LineDirectiveKind kind;
+
+        protected LineOrSpanDirective(Context cx, T trivia, LineDirectiveKind k)
             : base(cx, trivia)
         {
+            kind = k;
         }
 
         protected override void PopulatePreprocessor(TextWriter trapFile)
         {
+            trapFile.directive_lines(this, kind);
+
             if (!string.IsNullOrWhiteSpace(Symbol.File.ValueText))
             {
                 var file = File.Create(Context, Symbol.File.ValueText);

csharp/extractor/Semmle.Extraction.CSharp/Entities/PreprocessorDirectives/LineSpanDirective.cs

@@ -8,25 +8,24 @@ namespace Semmle.Extraction.CSharp.Entities
     internal class LineSpanDirective : LineOrSpanDirective<LineSpanDirectiveTriviaSyntax>
     {
         private LineSpanDirective(Context cx, LineSpanDirectiveTriviaSyntax trivia)
-            : base(cx, trivia) { }
+            : base(cx, trivia, LineDirectiveKind.Span) { }
+
         public static LineSpanDirective Create(Context cx, LineSpanDirectiveTriviaSyntax line) =>
             LineSpanDirectiveFactory.Instance.CreateEntity(cx, line, line);
 
         protected override void PopulatePreprocessor(TextWriter trapFile)
         {
-            trapFile.directive_lines(this, LineDirectiveKind.Span);
-
             var startLine = (int)Symbol.Start.Line.Value!;
             var startColumn = (int)Symbol.Start.Character.Value!;
             var endLine = (int)Symbol.End.Line.Value!;
             var endColumn = (int)Symbol.End.Character.Value!;
             trapFile.directive_line_span(this, startLine, startColumn, endLine, endColumn);
 
-            var offset = Symbol.CharacterOffset.Value;
-            if (offset is not null)
+            if (Symbol.CharacterOffset.Value is int offset)
             {
-                trapFile.directive_line_offset(this, (int)offset);
+                trapFile.directive_line_offset(this, offset);
             }
+
             base.PopulatePreprocessor(trapFile);
         }
 

csharp/ql/lib/semmle/code/csharp/Preprocessor.qll

@@ -208,7 +208,9 @@ class HiddenLineDirective extends LineDirective {
   override string getAPrimaryQlClass() { result = "HiddenLineDirective" }
 }
 
-abstract private class NumericOrSpanLineDirective extends LineDirective {
+private class NumericOrSpanLineDirective extends LineDirective {
+  NumericOrSpanLineDirective() { directive_lines(this, [2, 3]) }
+
   /** Gets the referenced file of this directive. */
   File getReferencedFile() { directive_line_file(this, result) }
 }
@@ -234,7 +236,7 @@ class SpanLineDirective extends NumericOrSpanLineDirective {
   /** Gets the offset of this directive. */
   int getOffset() { directive_line_offset(this, result) }
 
-  /** Gets the span of this directive. */
+  /** Holds if the specified start and end positions match this SpanLineDirective. */
   predicate span(int startLine, int startColumn, int endLine, int endColumn) {
     directive_line_span(this, startLine, startColumn, endLine, endColumn)
   }