better diagnosis

Macros/PostgresRecordMacro/Diagnoser.swift

@@ -2,8 +2,10 @@ import SwiftSyntax
 import SwiftSyntaxMacros
 import SwiftDiagnostics
 
-struct Diagnoser<Context: MacroExpansionContext> {
-    let context: Context
+struct Diagnoser {
+    let context: any MacroExpansionContext
+
+    static var shared: Diagnoser! = nil
 
     func cannotConformToProtocol(
         name: String,
@@ -16,12 +18,7 @@ struct Diagnoser<Context: MacroExpansionContext> {
             position: old.position,
             message: diagnosis.diagnosticMessage,
             highlights: nil,
-            notes: [],
-            fixIt: .replace(
-                message: diagnosis.fixItMessage,
-                oldNode: old,
-                newNode: new
-            )
+            notes: []
         ))
     }
 
@@ -32,11 +29,7 @@ struct Diagnoser<Context: MacroExpansionContext> {
             position: node.position,
             message: diagnosis.diagnosticMessage,
             highlights: nil,
-            notes: [],
-            fixIt: .init(
-                message: diagnosis.fixItMessage,
-                changes: []
-            )
+            notes: []
         ))
     }
 
@@ -47,11 +40,7 @@ struct Diagnoser<Context: MacroExpansionContext> {
             position: node.position,
             message: diagnosis.diagnosticMessage,
             highlights: nil,
-            notes: [],
-            fixIt: .init(
-                message: diagnosis.fixItMessage,
-                changes: []
-            )
+            notes: []
         ))
     }
 }
@@ -69,9 +58,9 @@ private enum Diagnosis: Error {
             case let .cannotConformToProtocol(proto):
                 return "Simultaneous conformance to '\(proto)' is not supported"
             case let .unsupportedPattern(pattern):
-                return "Pattern of '\(pattern)' is unsupported. Please file and issue in at https://github.com/vapor/postgres-kit/issues"
+                return "Pattern of '\(pattern)' is unsupported. As a workaround, try to use a more common pattern. Please file and issue in at https://github.com/vapor/postgres-kit/issues"
             case let .typeSyntaxNotFound(name):
-                return "Type declaration was not found for property '\(name)'."
+                return "Type declaration was not found for property '\(name)'. Please provide an explicit type"
             }
         }
 
@@ -91,10 +80,8 @@ private enum Diagnosis: Error {
             switch parent {
             case let .cannotConformToProtocol(proto):
                 return "Remove conformance to '\(proto)'"
-            case .unsupportedPattern:
-                return "As a workaround, try to use a more common pattern."
-            case .typeSyntaxNotFound:
-                return "Please provide an explicit type."
+            case .unsupportedPattern, .typeSyntaxNotFound:
+                return ""
             }
         }
 

Macros/PostgresRecordMacro/MacroError.swift

@@ -2,13 +2,16 @@ import SwiftDiagnostics
 
 enum MacroError: Error {
     case isNotStruct
+    case vagueError
 }
 
 extension MacroError: DiagnosticMessage {
     var message: String {
         switch self {
         case .isNotStruct:
             return "Only 'struct's are supported"
+        case .vagueError:
+            return "'PostgresRecord' macro expansion failed"
         }
     }
 

Macros/PostgresRecordMacro/PostgresRecordMacroType.swift

@@ -11,7 +11,7 @@ public enum PostgresRecordMacroType: ExtensionMacro {
         in context: some MacroExpansionContext
     ) throws -> [ExtensionDeclSyntax] {
         if declaration.hasError { return [] }
-        let diagnoser = Diagnoser(context: context)
+        Diagnoser.shared = Diagnoser(context: context)
 
         guard let structDecl = declaration.as(StructDeclSyntax.self) else {
             throw MacroError.isNotStruct
@@ -24,7 +24,7 @@ public enum PostgresRecordMacroType: ExtensionMacro {
             let proto = inheritedTypes[idx]
             let name = proto.trimmedDescription
             if forbiddenProtocols.contains(name) {
-                diagnoser.cannotConformToProtocol(
+                Diagnoser.shared.cannotConformToProtocol(
                     name: name,
                     old: structDecl,
                     new: structDecl.removingInheritedType(at: idx)
@@ -35,15 +35,16 @@ public enum PostgresRecordMacroType: ExtensionMacro {
 
         let members = structDecl.memberBlock.members
         let variableDecls = members.compactMap { $0.decl.as(VariableDeclSyntax.self) }
-        let variables = try variableDecls.flatMap {
-            try Variable.parse(from: $0, diagnoser: diagnoser)
-        }.filter {
-            !($0.isStatic || $0.isComputed)
-        }
+        let storedVariables = try variableDecls
+            .flatMap(Variable.parse(from:))
+            .filter { !($0.isStatic || $0.isComputed) }
 
         let name = structDecl.name.trimmedDescription
-        let initializer = variables.makePostgresRecordInit(name: name, accessLevel: accessLevel)
-        let codingKeys = variables.makeCodingKeys(accessLevel: accessLevel)
+        let initializer = try storedVariables.makePostgresRecordInit(
+            name: name,
+            accessLevel: accessLevel
+        )
+        let codingKeys = storedVariables.makeCodingKeys(accessLevel: accessLevel)
         let postgresRecord = try ExtensionDeclSyntax("""
         extension \(raw: name): PostgresRecord {
         \(raw: initializer)

Macros/PostgresRecordMacro/Variable+init.swift

@@ -1,8 +1,8 @@
 import SwiftSyntax
 
 extension [Variable] {
-    func makePostgresRecordInit(name: String, accessLevel: String) -> String {
-        """
+    func makePostgresRecordInit(name: String, accessLevel: String) throws -> String {
+        try """
         \(accessLevel)init(
             _from row: PostgresRow,
             context: PostgresDecodingContext<some PostgresJSONDecoder>,
@@ -20,8 +20,22 @@ extension [Variable] {
         """
     }
 
-    private func makeType() -> String {
-        "(\(self.map(\.type.description).joined(separator: ","))).self"
+    private func makeType() throws -> String {
+        let count = self.count
+        let variables = self.compactMap { variable -> Variable? in
+            if variable.type == nil {
+                Diagnoser.shared.typeSyntaxNotFound(name: variable.name, node: variable.binding)
+                return nil
+            } else {
+                return variable
+            }
+        }
+        /// Some variable had unexpected type.
+        if count != variables.count {
+            throw MacroError.vagueError
+        } else {
+            return "(\(variables.map(\.type!.description).joined(separator: ","))).self"
+        }
     }
 
     private func makeInitializations() -> String {

Macros/PostgresRecordMacro/Variable.swift

@@ -5,35 +5,32 @@ struct Variable {
     let name: String
     let isStatic: Bool
     let isComputed: Bool
-    let type: ParsedType
+    let type: ParsedType?
+    let binding: PatternBindingSyntax
 
-    static func parse(
-        from element: VariableDeclSyntax,
-        diagnoser: Diagnoser<some MacroExpansionContext>
-    ) throws -> [Variable] {
+    static func parse(from element: VariableDeclSyntax) throws -> [Variable] {
         let isStatic = element.modifiers.contains(.static)
         return try element.bindings.compactMap { binding -> Variable? in
             let isComputed = binding.accessorBlock.map({ Self.isComputed($0.accessors) }) ?? false
             guard let pattern = binding.pattern.as(IdentifierPatternSyntax.self) else {
-                diagnoser.unsupportedPattern(
+                Diagnoser.shared.unsupportedPattern(
                     binding.pattern.trimmedDescription,
                     node: binding.pattern
                 )
                 return nil
             }
             let name = pattern.identifier.trimmed.text
 
-            guard let typeSyntax = binding.typeAnnotation?.type else {
-                diagnoser.typeSyntaxNotFound(name: name, node: binding)
-                return nil
+            let type = try binding.typeAnnotation.map {
+                try ParsedType(syntax: $0.type)
             }
-            let type = try ParsedType(syntax: typeSyntax)
 
             return Variable(
                 name: name,
                 isStatic: isStatic,
                 isComputed: isComputed,
-                type: type
+                type: type,
+                binding: binding
             )
         }
     }

Sources/PostgresKit/PostgresRecord.swift

@@ -31,7 +31,7 @@ public macro PostgresRecord() = #externalMacro(
 @PostgresRecord
 struct MyTable {
     let int: Int
-    let string: String
+    let string = ""
 
     static let name = ""
 }