Add a declModifier token precedence to represent the declaration modifiers

Author: StevenWong12

Sources/SwiftParser/Declarations.swift

@@ -1695,7 +1695,7 @@ extension Parser {
   @_spi(RawSyntax)
   public mutating func parseOperatorDeclaration() -> RawOperatorDeclSyntax {
 
-    let (unexpectedBeforeModifier, modifier) = self.expect(.keyword(.infix), .keyword(.postfix), .keyword(.prefix), default: .keyword(.prefix))
+    let (unexpectedBeforeModifier, modifier) = self.expect(.keyword(.infix), .keyword(.postfix), .keyword(.prefix), default: .keyword(.prefix), overrideRecoveryPrecedence: .declKeyword)
 
     let (unexpectedBeforeOperator, operatorKeyword) = self.expect(.keyword(.operator))
 

Sources/SwiftParser/Parser.swift

@@ -349,11 +349,12 @@ extension Parser {
   ///     a missing token of the requested kind.
   @inline(__always)
   mutating func expect(
-    _ spec: TokenSpec
+    _ spec: TokenSpec,
+    overrideRecoveryPrecedence: TokenPrecedence? = nil
   ) -> (unexpected: RawUnexpectedNodesSyntax?, token: RawTokenSyntax) {
     return expectImpl(
       consume: { $0.consume(if: spec) },
-      canRecoverTo: { $0.canRecoverTo(spec) },
+      canRecoverTo: { $0.canRecoverTo(spec, overrideRecoveryPrecedence: overrideRecoveryPrecedence) },
       makeMissing: { $0.missingToken(spec) }
     )
   }
@@ -369,11 +370,12 @@ extension Parser {
   mutating func expect(
     _ spec1: TokenSpec,
     _ spec2: TokenSpec,
-    default defaultKind: TokenSpec
+    default defaultKind: TokenSpec,
+    overrideRecoveryPrecedence: TokenPrecedence? = nil
   ) -> (unexpected: RawUnexpectedNodesSyntax?, token: RawTokenSyntax) {
     return expectImpl(
       consume: { $0.consume(if: spec1, spec2) },
-      canRecoverTo: { $0.canRecoverTo(spec1, spec2) },
+      canRecoverTo: { $0.canRecoverTo(spec1, spec2, overrideRecoveryPrecedence: overrideRecoveryPrecedence) },
       makeMissing: { $0.missingToken(defaultKind) }
     )
   }
@@ -390,11 +392,12 @@ extension Parser {
     _ spec1: TokenSpec,
     _ spec2: TokenSpec,
     _ spec3: TokenSpec,
-    default defaultKind: TokenSpec
+    default defaultKind: TokenSpec,
+    overrideRecoveryPrecedence: TokenPrecedence? = nil
   ) -> (unexpected: RawUnexpectedNodesSyntax?, token: RawTokenSyntax) {
     return expectImpl(
       consume: { $0.consume(if: spec1, spec2, spec3) },
-      canRecoverTo: { $0.canRecoverTo(spec1, spec2, spec3) },
+      canRecoverTo: { $0.canRecoverTo(spec1, spec2, spec3, overrideRecoveryPrecedence: overrideRecoveryPrecedence) },
       makeMissing: { $0.missingToken(defaultKind) }
     )
   }

Sources/SwiftParser/Recovery.swift

@@ -42,17 +42,19 @@ public struct RecoveryConsumptionHandle {
 extension Parser.Lookahead {
   /// See `canRecoverTo` that takes 3 specs.
   mutating func canRecoverTo(
-    _ spec: TokenSpec
+    _ spec: TokenSpec,
+    overrideRecoveryPrecedence: TokenPrecedence? = nil
   ) -> RecoveryConsumptionHandle? {
-    return canRecoverTo(spec, spec, spec)
+    return canRecoverTo(spec, spec, spec, overrideRecoveryPrecedence: overrideRecoveryPrecedence)
   }
 
   /// See `canRecoverTo` that takes 3 specs.
   mutating func canRecoverTo(
     _ spec1: TokenSpec,
-    _ spec2: TokenSpec
+    _ spec2: TokenSpec,
+    overrideRecoveryPrecedence: TokenPrecedence? = nil
   ) -> RecoveryConsumptionHandle? {
-    return canRecoverTo(spec1, spec2, spec1)
+    return canRecoverTo(spec1, spec2, spec1, overrideRecoveryPrecedence: overrideRecoveryPrecedence)
   }
 
   /// Tries eating tokens until it finds a token that matches `spec1`, `spec2` or `spec3`
@@ -65,11 +67,12 @@ extension Parser.Lookahead {
   mutating func canRecoverTo(
     _ spec1: TokenSpec,
     _ spec2: TokenSpec,
-    _ spec3: TokenSpec
+    _ spec3: TokenSpec,
+    overrideRecoveryPrecedence: TokenPrecedence? = nil
   ) -> RecoveryConsumptionHandle? {
     let initialTokensConsumed = self.tokensConsumed
 
-    let recoveryPrecedence = min(spec1.recoveryPrecedence, spec2.recoveryPrecedence, spec3.recoveryPrecedence)
+    let recoveryPrecedence = overrideRecoveryPrecedence ?? min(spec1.recoveryPrecedence, spec2.recoveryPrecedence, spec3.recoveryPrecedence)
     let shouldSkipOverNewlines = recoveryPrecedence.shouldSkipOverNewlines && spec1.allowAtStartOfLine && spec2.allowAtStartOfLine && spec3.allowAtStartOfLine
 
     while !self.at(.eof) {

Sources/SwiftParser/TokenPrecedence.swift

@@ -38,6 +38,7 @@ public enum TokenPrecedence: Comparable {
   case strongPunctuator
   /// The closing delimiter of `strongBracketed`
   case closingBrace
+  case declModifier
   /// Tokens that start a new declaration
   case declKeyword
   case openingPoundIf
@@ -81,12 +82,14 @@ public enum TokenPrecedence: Comparable {
         return 8
       case .closingBrace:
         return 9
-      case .declKeyword:
+      case .declModifier:
         return 10
-      case .openingPoundIf:
+      case .declKeyword:
         return 11
-      case .closingPoundIf:
+      case .openingPoundIf:
         return 12
+      case .closingPoundIf:
+        return 13
       }
     }
 
@@ -210,17 +213,22 @@ public enum TokenPrecedence: Comparable {
       // Return-like statements
       .break, .continue, .fallthrough, .return, .throw, .yield:
       self = .stmtKeyword
+    // MARK: Decl Modifiers
+    case
+      // Operator Modifiers
+        .infix, .prefix, .postfix,
+      // Access modifiers
+        .fileprivate, .internal, .private, .public, .static:
+      self = .declModifier
     // MARK: Decl keywords
     case  // Types
     .associatedtype, .class, .enum, .extension, .protocol, .struct, .typealias,
-      // Access modifiers
-      .fileprivate, .internal, .private, .public, .static,
       // Functions
       .deinit, .func, .`init`, .subscript,
       // Variables
       .let, .var,
       // Operator stuff
-      .operator, .precedencegroup, .infix, .prefix, .postfix,
+      .operator, .precedencegroup,
       // Misc
       .import:
       self = .declKeyword

Tests/SwiftParserTest/translated/OperatorDeclTests.swift

@@ -502,6 +502,17 @@ final class OperatorDeclTests: XCTestCase {
       ]
     )
   }
+  
+  func testOperatorDecl126() {
+    assertParse(
+      """
+      1️⃣private(set) infix operator ~~~
+      """,
+      diagnostics: [
+        DiagnosticSpec(message: "unexpected code 'private(set)' before operator declaration")
+      ]
+    )
+  }
 
   func testIdentifierAsOperatorName() {
     assertParse(