Align child boxes with parent line.

Author: DougGregor

Sources/SwiftDiagnostics/DiagnosticsFormatter.swift

@@ -56,9 +56,10 @@ public struct DiagnosticsFormatter {
     tree: SyntaxType,
     diags: [Diagnostic],
     indentString: String,
-    suffixText: [(AbsolutePosition, String)]
+    suffixText: [(AbsolutePosition, String)],
+    sourceLocationConverter: SourceLocationConverter? = nil
   ) -> String {
-    let slc = SourceLocationConverter(file: "", tree: tree)
+    let slc = sourceLocationConverter ?? SourceLocationConverter(file: "", tree: tree)
 
     // First, we need to put each line and its diagnostics together
     var annotatedSourceLines = [AnnotatedSourceLine]()

Sources/SwiftDiagnostics/GroupedDiagnostics.swift

@@ -139,18 +139,25 @@ extension GroupedDiagnostics {
     formatter: DiagnosticsFormatter,
     indentString: String
   ) -> String {
+    let sourceFile = sourceFiles[sourceFileID.id]
+    let slc = SourceLocationConverter(
+      file: sourceFile.displayName,
+      tree: sourceFile.tree
+    )
+
+    let childPadding = String(slc.sourceLines.count + 1).count + 1;
+
     let childSources: [(AbsolutePosition, String)] = sourceFiles[sourceFileID.id].children.map { childBufferID in
       let childSource = annotateSource(
         childBufferID,
         formatter: formatter,
-        indentString: indentString + "   |"
+        indentString: indentString + String(repeating: " ", count: childPadding) + "|"
       )
 
       return (sourceFiles[childBufferID.id].parent!.1, childSource)
     }
 
     // If this is a nested source file, draw a box around it.
-    let sourceFile = sourceFiles[sourceFileID.id]
     let isRoot = sourceFile.parent == nil
     let prefixString: String
     let suffixString: String
@@ -182,7 +189,8 @@ extension GroupedDiagnostics {
         tree: sourceFile.tree,
         diags: sourceFile.diagnostics,
         indentString: indentString,
-        suffixText: childSources
+        suffixText: childSources,
+        sourceLocationConverter: slc
       ) + suffixString
   }
 }

Tests/SwiftDiagnosticsTest/GroupDiagnosticsFormatterTests.swift

@@ -115,14 +115,14 @@ final class GroupedDiagnosticsFormatterTests: XCTestCase {
       1 │ let pi = 3.14159
       2 │ #myAssert(pi == 3)
         ∣ ╰─ in expansion of macro 'myAssert' here
-         ╭-── #myAssert───────────────────────────────────────────────────────
-         |1 │ let __a = pi
-         |2 │ let __b = 3
-         |3 │ if !(__a == __b) {
-         |  ∣          ╰─ no matching operator '==' for types 'Double' and 'Int'
-         |4 │   fatalError("assertion failed: pi != 3")
-         |5 │ }
-         ╰-───────────────────────────────────────────────────────────────────
+        ╭-── #myAssert────────────────────────────────────────────────────────
+        |1 │ let __a = pi
+        |2 │ let __b = 3
+        |3 │ if !(__a == __b) {
+        |  ∣          ╰─ no matching operator '==' for types 'Double' and 'Int'
+        |4 │   fatalError("assertion failed: pi != 3")
+        |5 │ }
+        ╰-────────────────────────────────────────────────────────────────────
       3 │ print("hello"
         ∣              ╰─ expected ')' to end function call
 
@@ -184,18 +184,18 @@ final class GroupedDiagnosticsFormatterTests: XCTestCase {
       1 │ let pi = 3.14159
       2 │ #myAssert(pi == 3)
         ∣ ╰─ in expansion of macro 'myAssert' here
-         ╭-── #myAssert───────────────────────────────────────────────────────
-         |1 │ let __a = pi
-         |2 │ let __b = 3
-         |3 │ if #invertedEqualityCheck(__a, __b) {
-         |  ∣    ╰─ in expansion of macro 'invertedEqualityCheck' here
-         |   ╭-── #invertedEqualityCheck──────────────────────────────────────
-         |   |1 │ !(__a == __b)
-         |   |  ∣       ╰─ no matching operator '==' for types 'Double' and 'Int'
-         |   ╰-───────────────────────────────────────────────────────────────
-         |4 │   fatalError("assertion failed: pi != 3")
-         |5 │ }
-         ╰-───────────────────────────────────────────────────────────────────
+        ╭-── #myAssert────────────────────────────────────────────────────────
+        |1 │ let __a = pi
+        |2 │ let __b = 3
+        |3 │ if #invertedEqualityCheck(__a, __b) {
+        |  ∣    ╰─ in expansion of macro 'invertedEqualityCheck' here
+        |  ╭-── #invertedEqualityCheck────────────────────────────────────────
+        |  |1 │ !(__a == __b)
+        |  |  ∣       ╰─ no matching operator '==' for types 'Double' and 'Int'
+        |  ╰-─────────────────────────────────────────────────────────────────
+        |4 │   fatalError("assertion failed: pi != 3")
+        |5 │ }
+        ╰-────────────────────────────────────────────────────────────────────
       3 │ print("hello"
         ∣              ╰─ expected ')' to end function call