Merge branch 'main' of https://github.com/VerifyTests/Verify.SourceGenerators

Author: SimonCropp

src/Tests/SyntaxLocationTests.ConsistentLocation.verified.txt

@@ -1 +1,7 @@
-: (1,0)-(1,14)
+/*
+class Foo {
+void Bar() { }
+^^^^^^^^^^^^^^
+}
+*/
+theFile.cs: (1,0)-(1,14)

src/Tests/SyntaxLocationTests.cs

@@ -11,7 +11,7 @@ void Bar() { }
             """;
 
         var source = SourceText.From(sourceText);
-        var syntaxTree = SyntaxFactory.ParseSyntaxTree(source);
+        var syntaxTree = SyntaxFactory.ParseSyntaxTree(source, path: "theFile.cs");
 
         var methodDeclarationSyntax = syntaxTree
             .GetRoot()

src/Verify.SourceGenerators/Converters/LocationConverter.cs

@@ -1,6 +1,37 @@
 class LocationConverter :
     WriteOnlyJsonConverter<Location>
 {
-    public override void Write(VerifyJsonWriter writer, Location value) =>
-        writer.Serialize(value.GetMappedLineSpan());
-}
+    const int contextLines = 1;
+
+    public override void Write(VerifyJsonWriter writer, Location value)
+    {
+        var lineSpan = value.GetMappedLineSpan();
+
+        // Pretty-print the error with the source code snippet.
+        if (value.SourceTree is { } source)
+        {
+            var comment = new StringBuilder().AppendLine();
+            var lines = source.GetText().Lines;
+            var startLine = Math.Max(lineSpan.StartLinePosition.Line - contextLines, 0);
+            var endLine = Math.Min(lineSpan.EndLinePosition.Line + contextLines, lines.Count - 1);
+            for (var lineIdx = startLine; lineIdx <= endLine; lineIdx++)
+            {
+                var line = lines[lineIdx];
+                // print the source line
+                comment.AppendLine(line.ToString());
+                // print squiggly line highlighting the location
+                if (line.Span.Intersection(value.SourceSpan) is { } intersection)
+                {
+                    comment
+                        .Append(' ', intersection.Start - line.Start)
+                        .Append('^', intersection.Length)
+                        .AppendLine();
+                }
+            }
+            writer.WriteComment(comment.ToString());
+            writer.WriteWhitespace("\n");
+        }
+
+        writer.Serialize(lineSpan);
+    }
+}