Merge pull request swiftlang#2540 from tshortli/unknown-default

Resolve `switch covers known cases, but 'Enum' may have additional unknown values` warnings

Author: tshortli

CodeGeneration/Sources/generate-swift-syntax/templates/swiftparserdiagnostics/TokenNameForDiagnosticsFile.swift

@@ -29,6 +29,21 @@ let tokenNameForDiagnosticFile = SourceFileSyntax(leadingTrivia: copyrightHeader
         SwitchCaseSyntax("case .keyword(let keyword):") {
           StmtSyntax("return String(syntaxText: keyword.defaultText)")
         }
+        IfConfigDeclSyntax(
+          clauses: IfConfigClauseListSyntax {
+            IfConfigClauseSyntax(
+              poundKeyword: .poundIfToken(),
+              condition: ExprSyntax("RESILIENT_LIBRARIES"),
+              elements: .switchCases(
+                SwitchCaseListSyntax {
+                  SwitchCaseSyntax("@unknown default:") {
+                    StmtSyntax("fatalError()")
+                  }
+                }
+              )
+            )
+          }
+        )
       }
     }
   }

Sources/SwiftCompilerPluginMessageHandling/Diagnostics.swift

@@ -54,6 +54,9 @@ extension PluginMessage.Diagnostic.Severity {
     case .warning: self = .warning
     case .note: self = .note
     case .remark: self = .remark
+    #if RESILIENT_LIBRARIES
+    @unknown default: fatalError()
+    #endif
     }
   }
 }
@@ -122,6 +125,10 @@ extension PluginMessage.Diagnostic {
               to: .afterTrailingTrivia
             )
             text = newTrivia.description
+          #if RESILIENT_LIBRARIES
+          @unknown default:
+            fatalError()
+          #endif
           }
           guard let range = range else {
             return nil

Sources/SwiftCompilerPluginMessageHandling/PluginMacroExpansionContext.swift

@@ -153,6 +153,9 @@ class SourceManager {
     switch filePathMode {
     case .fileID: file = base.location.fileID
     case .filePath: file = base.location.fileName
+    #if RESILIENT_LIBRARIES
+    @unknown default: fatalError()
+    #endif
     }
 
     let localPosition = node.position(at: kind)
@@ -185,6 +188,10 @@ fileprivate extension Syntax {
       return self.endPositionBeforeTrailingTrivia
     case .afterTrailingTrivia:
       return self.endPosition
+    #if RESILIENT_LIBRARIES
+    @unknown default:
+      fatalError()
+    #endif
     }
   }
 }

Sources/SwiftOperators/OperatorTable+Semantics.swift

@@ -62,6 +62,10 @@ extension PrecedenceGroup {
         default:
           break
         }
+      #if RESILIENT_LIBRARIES
+      @unknown default:
+        fatalError()
+      #endif
       }
     }
   }

Sources/SwiftParser/StringLiteralRepresentedLiteralValue.swift

@@ -43,6 +43,10 @@ extension StringLiteralExprSyntax {
       case .expressionSegment:
         // Bail out if there are any interpolation segments.
         return nil
+      #if RESILIENT_LIBRARIES
+      @unknown default:
+        fatalError()
+      #endif
       }
     }
 

Sources/SwiftParser/StringLiterals.swift

@@ -167,7 +167,10 @@ extension Parser {
     openQuoteHasTrailingNewline: Bool,
     middleSegments: inout [RawStringLiteralSegmentListSyntax.Element]
   ) -> Bool {
-    switch middleSegments.last {
+    guard let segment = middleSegments.last else {
+      return openQuoteHasTrailingNewline
+    }
+    switch segment {
     case .stringSegment(let lastMiddleSegment):
       if !lastMiddleSegment.content.trailingTriviaPieces.isEmpty {
         precondition(
@@ -218,8 +221,10 @@ extension Parser {
       }
     case .expressionSegment:
       return false
-    case nil:
-      return openQuoteHasTrailingNewline
+    #if RESILIENT_LIBRARIES
+    @unknown default:
+      fatalError()
+    #endif
     }
   }
 
@@ -282,6 +287,10 @@ extension Parser {
         if let rewrittenSegment = expressionIndentationChecker.checkIndentation(of: segment) {
           middleSegments[index] = .expressionSegment(rewrittenSegment)
         }
+      #if RESILIENT_LIBRARIES
+      @unknown default:
+        fatalError()
+      #endif
       }
     }
   }

Sources/SwiftParser/TokenPrecedence.swift

@@ -358,6 +358,10 @@ enum TokenPrecedence: Comparable {
       .wrt,
       .unsafe:
       self = .exprKeyword
+    #if RESILIENT_LIBRARIES
+    @unknown default:
+      fatalError()
+    #endif
     }
   }
 }

Sources/SwiftParserDiagnostics/LexerDiagnosticMessages.swift

@@ -230,6 +230,10 @@ public extension SwiftSyntax.TokenDiagnostic {
     case .unicodeCurlyQuote: return StaticTokenError.unicodeCurlyQuote
     case .unprintableAsciiCharacter: return StaticTokenError.unprintableAsciiCharacter
     case .unterminatedBlockComment: return StaticTokenError.unterminatedBlockComment
+    #if RESILIENT_LIBRARIES
+    @unknown default:
+      fatalError()
+    #endif
     }
   }
 

Sources/SwiftParserDiagnostics/SyntaxExtensions.swift

@@ -216,6 +216,10 @@ extension TypeSpecifierListSyntax {
       switch specifier {
       case .simpleTypeSpecifier(let specifier): return specifier.specifier
       case .lifetimeTypeSpecifier: return nil
+      #if RESILIENT_LIBRARIES
+      @unknown default:
+        fatalError()
+      #endif
       }
     }
   }

Sources/SwiftParserDiagnostics/generated/TokenNameForDiagnostics.swift

@@ -117,6 +117,9 @@ extension TokenKind {
       return "wildcard"
     case .keyword(let keyword):
       return String(syntaxText: keyword.defaultText)
+    #if RESILIENT_LIBRARIES
+    @unknown default:fatalError()
+    #endif
     }
   }
 }