Address review comments

Author: ahoppen

Sources/SwiftParser/Diagnostics/ParserDiagnosticMessages.swift

@@ -150,15 +150,16 @@ public struct MissingNodeError: ParserError {
     if let parent = missingNode.parent,
         let childName = parent.childNameForDiagnostics(missingNode.index) {
       message = "Expected \(childName)"
-      if let parent = missingNode.parent,
-          let parentTypeName = parent.nodeTypeNameForDiagnostics(inherit: false) {
+      if let parentTypeName = parent.nodeTypeNameForDiagnostics(inherit: false) {
         message += " of \(parentTypeName)"
         hasNamedParent = true
       }
     } else {
       message = "Expected \(missingNode.nodeTypeNameForDiagnostics() ?? "syntax")"
-      if let lastChild = missingNode.lastToken(viewMode: .fixedUp), lastChild.presence == .present {
-        message += " after '\(lastChild.text)'"
+      if let missingDecl = missingNode.as(MissingDeclSyntax.self), let lastModifier = missingDecl.modifiers?.last {
+        message += " after '\(lastModifier.name.text)' modifier"
+      } else if let missingDecl = missingNode.as(MissingDeclSyntax.self), missingDecl.attributes != nil {
+        message += " after attribute"
       } else if let previousToken = missingNode.previousToken(viewMode: .fixedUp), previousToken.presence == .present {
         message += " after '\(previousToken.text)'"
       }

Sources/SwiftParser/Directives.swift

@@ -89,7 +89,7 @@ extension Parser {
         do {
           var elementsProgress = LoopProgressCondition()
           while !self.at(any: [.eof, .poundElseKeyword, .poundElseifKeyword, .poundEndifKeyword]) && elementsProgress.evaluate(currentToken) {
-            guard let element = parseElement(&self), element.raw.byteLength > 0 else {
+            guard let element = parseElement(&self), !element.isEmpty else {
               break
             }
             elements.append(element)

Sources/SwiftParser/Expressions.swift

@@ -1620,7 +1620,7 @@ extension Parser {
           let element = RawArrayElementSyntax(
             expression: el, trailingComma: comma, arena: self.arena
           )
-          if element.raw.byteLength == 0 {
+          if element.isEmpty {
             break COLLECTION_LOOP
           } else {
             elements.append(RawSyntax(element))
@@ -1634,7 +1634,7 @@ extension Parser {
             trailingComma: comma,
             arena: self.arena
           )
-          if element.raw.byteLength == 0 {
+          if element.isEmpty {
             break COLLECTION_LOOP
           } else {
             elements.append(RawSyntax(element))

Sources/SwiftParser/TopLevel.swift

@@ -119,7 +119,7 @@ extension Parser {
     let item = self.parseItem(isAtTopLevel: isAtTopLevel)
     let semi = self.consume(if: .semicolon)
 
-    if item.raw.byteLength == 0 && semi == nil {
+    if item.isEmpty && semi == nil {
       return nil
     }
     return .init(item: item, semicolon: semi, errorTokens: nil, arena: self.arena)

Sources/SwiftSyntax/Raw/RawSyntaxNodeProtocol.swift

@@ -42,6 +42,10 @@ public extension RawSyntaxNodeProtocol {
   func write<Target>(to target: inout Target) where Target : TextOutputStream {
     raw.write(to: &target)
   }
+
+  var isEmpty: Bool {
+    return raw.byteLength == 0
+  }
 }
 
 /// `RawSyntax` itself conforms to `RawSyntaxNodeProtocol`.

Tests/SwiftParserTest/Attributes.swift

@@ -11,7 +11,7 @@ final class AttributeTests: XCTestCase {
       }
       """,
       diagnostics: [
-        DiagnosticSpec(locationMarker: "DIAG_2", message: "Expected declaration"),
+        DiagnosticSpec(locationMarker: "DIAG_2", message: "Expected declaration after attribute"),
         DiagnosticSpec(locationMarker: "DIAG_1", message: "Expected 'for' in attribute argument"),
         DiagnosticSpec(locationMarker: "DIAG_1", message: "Expected ':' in attribute argument"),
         DiagnosticSpec(locationMarker: "DIAG_2", message: "Expected ')' to end attribute"),
@@ -42,20 +42,20 @@ final class AttributeTests: XCTestCase {
       @_specialize(e#^DIAG^#
       """,
       diagnostics: [
-        DiagnosticSpec(message: "Expected declaration"),
+        DiagnosticSpec(message: "Expected declaration after attribute"),
         DiagnosticSpec(message: "Expected ':' in attribute argument"),
         DiagnosticSpec(message: "Expected ')' to end attribute"),
       ]
     )
   }
-  
+
   func testMultipleInvalidSpecializeParams() {
     AssertParse(
       """
       @_specialize(e#^DIAG_1^#, exported#^DIAG_2^#)#^DIAG_3^#
       """,
       diagnostics: [
-        DiagnosticSpec(locationMarker: "DIAG_3", message: "Expected declaration after ')'"),
+        DiagnosticSpec(locationMarker: "DIAG_3", message: "Expected declaration after attribute"),
         DiagnosticSpec(locationMarker: "DIAG_1", message: "Expected ':' in attribute argument"),
         DiagnosticSpec(locationMarker: "DIAG_2", message: "Expected ':' in attribute argument"),
         DiagnosticSpec(locationMarker: "DIAG_2", message: "Expected 'false' in attribute argument"),

Tests/SwiftParserTest/Declarations.swift

@@ -553,7 +553,7 @@ final class DeclarationTests: XCTestCase {
       }
       """,
       diagnostics: [
-        DiagnosticSpec(message: "Expected declaration after 'public' in struct")
+        DiagnosticSpec(message: "Expected declaration after 'public' modifier in struct")
       ]
     )
   }
@@ -904,7 +904,7 @@ final class DeclarationTests: XCTestCase {
       diagnostics: [
         DiagnosticSpec(locationMarker: "OPENING_BRACE", message: "Expected '{' to start struct"),
         DiagnosticSpec(locationMarker: "AFTER_POUND_IF", message: "Expected condition of conditional compilation clause"),
-        DiagnosticSpec(locationMarker: "END", message: "Expected declaration after '@' in conditional compilation clause"),
+        DiagnosticSpec(locationMarker: "END", message: "Expected declaration after attribute in conditional compilation clause"),
         DiagnosticSpec(locationMarker: "END", message: "Expected name of attribute"),
         DiagnosticSpec(locationMarker: "END", message: "Expected '#endif' in conditional compilation block"),
         DiagnosticSpec(locationMarker: "END", message: "Expected '}' to end struct")

Tests/SwiftParserTest/Directives.swift

@@ -148,9 +148,9 @@ final class DirectiveTests: XCTestCase {
       }
       """,
       diagnostics: [
-        DiagnosticSpec(locationMarker: "DIAG_1", message: "Expected declaration after 'foo' in conditional compilation clause"),
-        DiagnosticSpec(locationMarker: "DIAG_2", message: "Expected declaration after 'foo' in conditional compilation clause"),
-        DiagnosticSpec(locationMarker: "DIAG_3", message: "Expected declaration after 'frozen' in conditional compilation clause"),
+        DiagnosticSpec(locationMarker: "DIAG_1", message: "Expected declaration after attribute in conditional compilation clause"),
+        DiagnosticSpec(locationMarker: "DIAG_2", message: "Expected declaration after attribute in conditional compilation clause"),
+        DiagnosticSpec(locationMarker: "DIAG_3", message: "Expected declaration after attribute in conditional compilation clause"),
       ]
     )
   }