Apply this policy more broadly to all backtick-enclosed identifiers

Author: stmontgomery

Sources/TestingMacros/Support/Additions/FunctionDeclSyntaxAdditions.swift

@@ -11,7 +11,6 @@
 import SwiftSyntax
 import SwiftSyntaxBuilder
 import SwiftSyntaxMacros
-import SwiftParser
 
 extension FunctionDeclSyntax {
   /// Whether or not this function a `static` or `class` function.
@@ -39,7 +38,7 @@ extension FunctionDeclSyntax {
   /// colons.
   var completeName: DeclReferenceExprSyntax {
     func possiblyRaw(_ token: TokenSyntax) -> TokenSyntax {
-      if let rawIdentifier = token.rawIdentifier, !rawIdentifier.isValidSwiftIdentifier(for: .memberAccess) {
+      if let rawIdentifier = token.rawIdentifier {
         return .identifier("`\(rawIdentifier)`")
       }
       return .identifier(token.textWithoutBackticks)

Sources/TestingMacros/Support/Additions/TokenSyntaxAdditions.swift

@@ -35,7 +35,7 @@ extension TokenSyntax {
   /// token, or `nil` if it does not represent one.
   var rawIdentifier: String? {
     let (textWithoutBackticks, backticksRemoved) = _textWithoutBackticks
-    if backticksRemoved {
+    if backticksRemoved, !textWithoutBackticks.isValidSwiftIdentifier(for: .memberAccess) {
       return textWithoutBackticks
     }
 

Sources/TestingMacros/Support/AttributeDiscovery.swift

@@ -11,7 +11,6 @@
 import SwiftSyntax
 import SwiftSyntaxBuilder
 import SwiftSyntaxMacros
-import SwiftParser
 
 /// A syntax rewriter that removes leading `Self.` tokens from member access
 /// expressions in a syntax tree.
@@ -139,20 +138,17 @@ struct AttributeInfo {
       }
     }
 
-    // If this declaration has a raw identifier name, implicitly use the content
-    // of that raw identifier as its display name.
+    // If this declaration's name is surrounded by backticks, it may be an
+    // escaped or raw identifier. If it has an explicitly-specified display name
+    // string, honor that, otherwise use the content of the backtick-enclosed
+    // name as the display name.
     if let namedDecl = declaration.asProtocol((any NamedDeclSyntax).self),
-       let rawIdentifier = namedDecl.name.rawIdentifier {
-      // Disallow having an explicit display name for tests and suites with raw
-      // identifier names as it's redundant and potentially confusing. An
-      // exception to this rule is if the content of the raw identifier is not a
-      // valid identifier on its own. For example:
-      //
-      //   @Test("...") func `subscript`() { ... }
-      if let displayName, let displayNameArgument, !rawIdentifier.isValidSwiftIdentifier(for: .memberAccess) {
+       case let nameWithoutBackticks = namedDecl.name.textWithoutBackticks,
+       nameWithoutBackticks != namedDecl.name.text {
+      if let displayName, let displayNameArgument {
         context.diagnose(.declaration(namedDecl, hasExtraneousDisplayName: displayName, fromArgument: displayNameArgument, using: attribute))
       } else {
-        displayName = StringLiteralExprSyntax(content: rawIdentifier)
+        displayName = StringLiteralExprSyntax(content: nameWithoutBackticks)
       }
     }
 

Tests/TestingMacrosTests/TestDeclarationMacroTests.swift

@@ -263,14 +263,48 @@ struct TestDeclarationMacroTests {
     }
   }
 
-  @Test("No diagnostics are emitted for tests with both a raw identifier name and explicit display name when deemed non-redundant", arguments: [
-    #"@Test("Class") func `class`()"#,
-    #"@Test("Struct") func `struct`()"#,
-    #"@Test("Subscript") func `subscript`()"#,
+  @Test("Warning diagnostics which include fix-its emitted on API misuse", arguments: [
+    #"@Test("Subscript") func `subscript`()"#:
+      (
+        message: "Attribute 'Test' specifies display name 'Subscript' for function with implicit display name 'subscript'",
+        fixIts: [
+          ExpectedFixIt(
+            message: "Remove 'Subscript'",
+            changes: [.replace(oldSourceCode: #""Subscript""#, newSourceCode: "")]
+          ),
+          ExpectedFixIt(
+            message: "Rename 'subscript'",
+            changes: [.replace(oldSourceCode: "`subscript`", newSourceCode: "\(EditorPlaceholderExprSyntax("name"))")]
+          ),
+        ]
+      ),
   ])
-  func nonRedundantRawIdentifierDisplayName(input: String) throws {
+  func apiMisuseWarningsIncludingFixIts(input: String, expectedDiagnostic: (message: String, fixIts: [ExpectedFixIt])) throws {
     let (_, diagnostics) = try parse(input)
-    #expect(diagnostics.isEmpty)
+
+    #expect(diagnostics.count == 1)
+    let diagnostic = try #require(diagnostics.first)
+    #expect(diagnostic.diagMessage.severity == .warning)
+    #expect(diagnostic.message == expectedDiagnostic.message)
+
+    try #require(diagnostic.fixIts.count == expectedDiagnostic.fixIts.count)
+    for (fixIt, expectedFixIt) in zip(diagnostic.fixIts, expectedDiagnostic.fixIts) {
+      #expect(fixIt.message.message == expectedFixIt.message)
+
+      try #require(fixIt.changes.count == expectedFixIt.changes.count)
+      for (change, expectedChange) in zip(fixIt.changes, expectedFixIt.changes) {
+        switch (change, expectedChange) {
+        case let (.replace(oldNode, newNode), .replace(expectedOldSourceCode, expectedNewSourceCode)):
+          let oldSourceCode = String(describing: oldNode.formatted())
+          #expect(oldSourceCode == expectedOldSourceCode)
+
+          let newSourceCode = String(describing: newNode.formatted())
+          #expect(newSourceCode == expectedNewSourceCode)
+        default:
+          Issue.record("Change \(change) differs from expected change \(expectedChange)")
+        }
+      }
+    }
   }
 
   @Test("Raw identifier is detected")

Tests/TestingTests/Support/GraphTests.swift

@@ -53,8 +53,7 @@ struct GraphTests {
     #expect(graph.subgraph(at: "C2", "C3")?.value == 2468)
   }
 
-  @Test("subscript([K]) operator")
-  func `subscript`() {
+  @Test func `subscript([K]) operator`() {
     let graph = Graph<String, Int>(value: 123, children: [
       "C1": Graph(value: 456),
       "C2": Graph(value: 789, children: [