chore: improve diagnostic flow

Author: EnesKaraosman

Example/Example.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved

@@ -1,4 +1,5 @@
 {
+  "originHash" : "6a124a9d1b72d90a9989b97c9c4aeef9531842ce12391f89eaad7e6d57fb6fb4",
   "pins" : [
     {
       "identity" : "fakery",
@@ -14,10 +15,10 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/apple/swift-syntax.git",
       "state" : {
-        "revision" : "fa8f95c2d536d6620cc2f504ebe8a6167c9fc2dd",
-        "version" : "510.0.1"
+        "revision" : "303e5c5c36d6a558407d364878df131c3546fad8",
+        "version" : "510.0.2"
       }
     }
   ],
-  "version" : 2
+  "version" : 3
 }

Package.resolved

@@ -14,26 +14,26 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/pointfreeco/swift-macro-testing",
       "state" : {
-        "revision" : "5c4a1b9d7c23cd5c08ea50677d8e89080365cb00",
-        "version" : "0.4.0"
+        "revision" : "20c1a8f3b624fb5d1503eadcaa84743050c350f4",
+        "version" : "0.5.2"
       }
     },
     {
       "identity" : "swift-snapshot-testing",
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/pointfreeco/swift-snapshot-testing",
       "state" : {
-        "revision" : "625ccca8570773dd84a34ee51a81aa2bc5a4f97a",
-        "version" : "1.16.0"
+        "revision" : "6d932a79e7173b275b96c600c86c603cf84f153c",
+        "version" : "1.17.4"
       }
     },
     {
       "identity" : "swift-syntax",
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/apple/swift-syntax.git",
       "state" : {
-        "revision" : "303e5c5c36d6a558407d364878df131c3546fad8",
-        "version" : "510.0.2"
+        "revision" : "2bc86522d115234d1f588efe2bcb4ce4be8f8b82",
+        "version" : "510.0.3"
       }
     }
   ],

Sources/LoremSwiftifyMacros/Diagnostic.swift

@@ -0,0 +1,31 @@
+//
+//  Diagnostic.swift
+//  
+//
+//  Created by Enes Karaosman on 10.08.2024.
+//
+
+import SwiftDiagnostics
+
+enum LoremSwiftifyMacroDiagnostic: DiagnosticMessage, Error {
+    case unsupportedType
+    case noMemberToMock
+    case noEnumCase
+
+    var message: String {
+        switch self {
+        case .unsupportedType:
+            return "You can only lorem struct, class and enum"
+        case .noMemberToMock:
+            return "There is no member to lorem"
+        case .noEnumCase:
+            return "There is no enum case to lorem"
+        }
+    }
+
+    var diagnosticID: SwiftDiagnostics.MessageID {
+        MessageID(domain: "Swift", id: "LoremSwiftifyMacroDiagnostic.\(self)")
+    }
+
+    var severity: SwiftDiagnostics.DiagnosticSeverity { .error }
+}

Sources/LoremSwiftifyMacros/LoremSwiftifyMacro.swift

@@ -6,31 +6,6 @@ import SwiftSyntaxMacros
 
 let protocolName = "LoremIpsumize"
 
-// TODO: Use better diagnostics
-// https://github.com/apple/swift-syntax/blob/main/Examples/Sources/MacroExamples/Implementation/Diagnostics.swift
-enum LoremSwiftifyMacroDiagnostic: DiagnosticMessage, Error {
-    case unsupportedType
-    case noMemberToMock
-    case noEnumCase
-
-    var message: String {
-        switch self {
-        case .unsupportedType:
-            return "You can only lorem struct, class and enum"
-        case .noMemberToMock:
-            return "There is no member to lorem"
-        case .noEnumCase:
-            return "There is no enum case to lorem"
-        }
-    }
-
-    var diagnosticID: SwiftDiagnostics.MessageID {
-        MessageID(domain: "Swift", id: "LoremSwiftifyMacroDiagnostic.\(self)")
-    }
-
-    var severity: SwiftDiagnostics.DiagnosticSeverity { .error }
-}
-
 public enum LoremMacro: PeerMacro {
     public static func expansion(of node: SwiftSyntax.AttributeSyntax, providingPeersOf declaration: some SwiftSyntax.DeclSyntaxProtocol, in context: some SwiftSyntaxMacros.MacroExpansionContext) throws -> [SwiftSyntax.DeclSyntax] {
         // LoremMacro does not generate something, this will be controlled in LoremSwiftify macro
@@ -52,7 +27,7 @@ public enum LoremSwiftifyMacro: ExtensionMacro {
 
             context.diagnose(.init(node: declaration, message: LoremSwiftifyMacroDiagnostic.unsupportedType))
 
-            throw LoremSwiftifyMacroDiagnostic.unsupportedType
+            return []
         }
 
         let extensionDecl = try ExtensionDeclSyntax(

Sources/LoremSwiftifyMacros/SupportedTypes/LoremSwiftifyClass.swift

@@ -20,6 +20,8 @@ class LoremSwiftifyClass {
     ) throws -> DeclSyntax {
         if declaration.memberBlock.members.isEmpty {
             context.diagnose(.init(node: declaration, message: LoremSwiftifyMacroDiagnostic.noMemberToMock))
+            
+            return ""
         }
 
         return try LoremSwiftifyMacroParsingShared.handleClassOrStructDeclSyntax(

Sources/LoremSwiftifyMacros/SupportedTypes/LoremSwiftifyEnum.swift

@@ -24,6 +24,8 @@ class LoremSwiftifyEnum {
 
         if cases.isEmpty {
             context.diagnose(.init(node: declaration, message: LoremSwiftifyMacroDiagnostic.noEnumCase))
+            
+            return ""
         }
 
         let caseExpr = generateEnumCreationFunctionBody(for: cases)

Sources/LoremSwiftifyMacros/SupportedTypes/LoremSwiftifyStruct.swift

@@ -20,6 +20,8 @@ class LoremSwiftifyStruct {
     ) throws -> DeclSyntax {
         if declaration.memberBlock.members.isEmpty {
             context.diagnose(.init(node: declaration, message: LoremSwiftifyMacroDiagnostic.noMemberToMock))
+            
+            return ""
         }
 
         return try LoremSwiftifyMacroParsingShared.handleClassOrStructDeclSyntax(