Replace assert by precondition in most places

CodeGeneration/Sources/SyntaxSupport/Node.swift

@@ -162,6 +162,6 @@ public class Node {
     self.elementsSeparatedByNewline = elementsSeparatedByNewline
 
     // For SyntaxCollections make sure that the elementName is set.
-    assert(!isSyntaxCollection || elementName != nil || element != "")
+    precondition(!isSyntaxCollection || elementName != nil || element != "")
   }
 }

CodeGeneration/Sources/Utils/SyntaxBuildableChild.swift

@@ -63,7 +63,7 @@ public extension Child {
   }
 
   /// If this node is a token that can't contain arbitrary text, generate a Swift
-  /// `assert` statement that verifies the variable with name var_name and of type
+  /// `precondition` statement that verifies the variable with name var_name and of type
   /// `TokenSyntax` contains one of the supported text options. Otherwise return `nil`.
   func generateAssertStmtTextChoices(varName: String) -> FunctionCallExprSyntax? {
     guard case .token(choices: let choices, requiresLeadingSpace: _, requiresTrailingSpace: _) = kind else {
@@ -79,7 +79,7 @@ public extension Child {
 
     let choicesTexts: [String]
     if tokenCanContainArbitraryText {
-      // Don't generate an assert statement if token can contain arbitrary text.
+      // Don't generate an precondition statement if token can contain arbitrary text.
       return nil
     } else if !choices.isEmpty {
       choicesTexts = choices.compactMap {
@@ -92,9 +92,9 @@ public extension Child {
       return nil
     }
 
-    var assertChoices: [ExprSyntax] = []
+    var preconditionChoices: [ExprSyntax] = []
     if type.isOptional {
-      assertChoices.append(
+      preconditionChoices.append(
         ExprSyntax(
           SequenceExprSyntax {
             IdentifierExprSyntax(identifier: .identifier(varName))
@@ -105,7 +105,7 @@ public extension Child {
       )
     }
     for textChoice in choicesTexts {
-      assertChoices.append(
+      preconditionChoices.append(
         ExprSyntax(
           SequenceExprSyntax {
             MemberAccessExprSyntax(base: type.forceUnwrappedIfNeeded(expr: IdentifierExprSyntax(identifier: .identifier(varName))), name: "text")
@@ -115,8 +115,8 @@ public extension Child {
         )
       )
     }
-    let disjunction = ExprListSyntax(assertChoices.flatMap { [$0, ExprSyntax(BinaryOperatorExprSyntax(text: "||"))] }.dropLast())
-    return FunctionCallExprSyntax(callee: ExprSyntax("assert")) {
+    let disjunction = ExprListSyntax(preconditionChoices.flatMap { [$0, ExprSyntax(BinaryOperatorExprSyntax(text: "||"))] }.dropLast())
+    return FunctionCallExprSyntax(callee: ExprSyntax("precondition")) {
       TupleExprElementSyntax(expression: SequenceExprSyntax(elements: disjunction))
     }
   }

CodeGeneration/Sources/Utils/SyntaxBuildableNode.swift

@@ -44,14 +44,14 @@ public extension Node {
 
   /// Assuming this node is a syntax collection, the type of its elements.
   var collectionElementType: SyntaxBuildableType {
-    assert(isSyntaxCollection)
+    precondition(isSyntaxCollection)
     return SyntaxBuildableType(syntaxKind: collectionElement)
   }
 
   /// Assuming this node has a single child without a default value, that child.
   var singleNonDefaultedChild: Child {
     let nonDefaultedParams = children.filter { $0.type.defaultInitialization == nil }
-    assert(nonDefaultedParams.count == 1)
+    precondition(nonDefaultedParams.count == 1)
     return nonDefaultedParams[0]
   }
 

CodeGeneration/Sources/generate-swiftsyntax/templates/swiftparser/ParserEntryFile.swift

@@ -78,8 +78,7 @@ let parserEntryFile = SourceFileSyntax(leadingTrivia: copyrightHeader) {
       """
       mutating func parseRemainder<R: RawSyntaxNodeProtocol>(into: R) -> R {
         guard !into.raw.kind.isSyntaxCollection, let layout = into.raw.layoutView else {
-          assertionFailure("Only support parsing of non-collection layout nodes")
-          return into
+          preconditionFailure("Only support parsing of non-collection layout nodes")
         }
 
         let remainingTokens = self.consumeRemainingTokens()
@@ -89,7 +88,7 @@ let parserEntryFile = SourceFileSyntax(leadingTrivia: copyrightHeader) {
 
         let existingUnexpected: [RawSyntax]
         if let unexpectedNode = layout.children[layout.children.count - 1] {
-           assert(unexpectedNode.is(RawUnexpectedNodesSyntax.self))
+           precondition(unexpectedNode.is(RawUnexpectedNodesSyntax.self))
            existingUnexpected = unexpectedNode.as(RawUnexpectedNodesSyntax.self).elements
         } else {
            existingUnexpected = []

CodeGeneration/Sources/generate-swiftsyntax/templates/swiftsyntax/RawSyntaxNodesFile.swift

@@ -129,7 +129,15 @@ let rawSyntaxNodesFile = SourceFileSyntax(leadingTrivia: copyrightHeader) {
       DeclSyntax(
         """
         init(raw: RawSyntax) {
-          assert(Self.isKindOf(raw))
+          precondition(Self.isKindOf(raw))
+          self.raw = raw
+        }
+        """
+      )
+
+      DeclSyntax(
+        """
+        private init(unchecked raw: RawSyntax) {
           self.raw = raw
         }
         """
@@ -139,7 +147,7 @@ let rawSyntaxNodesFile = SourceFileSyntax(leadingTrivia: copyrightHeader) {
         """
         public init?<Node: RawSyntaxNodeProtocol>(_ other: Node) {
           guard Self.isKindOf(other.raw) else { return nil }
-          self.init(raw: other.raw)
+          self.init(unchecked: other.raw)
         }
         """
       )
@@ -148,7 +156,7 @@ let rawSyntaxNodesFile = SourceFileSyntax(leadingTrivia: copyrightHeader) {
         DeclSyntax(
           """
           public init<Node: Raw\(raw: node.name)NodeProtocol>(_ other: Node) {
-            self.init(raw: other.raw)
+            self.init(unchecked: other.raw)
           }
           """
         )
@@ -167,7 +175,7 @@ let rawSyntaxNodesFile = SourceFileSyntax(leadingTrivia: copyrightHeader) {
                     ptr += 1
                   }
             }
-            self.init(raw: raw)
+            self.init(unchecked: raw)
           }
           """
         )
@@ -217,7 +225,7 @@ let rawSyntaxNodesFile = SourceFileSyntax(leadingTrivia: copyrightHeader) {
           } else {
             DeclSyntax("let raw = RawSyntax.makeEmptyLayout(kind: .\(raw: node.swiftSyntaxKind), arena: arena)")
           }
-          ExprSyntax("self.init(raw: raw)")
+          ExprSyntax("self.init(unchecked: raw)")
         }
 
         for (index, child) in node.children.enumerated() {

CodeGeneration/Sources/generate-swiftsyntax/templates/swiftsyntax/SyntaxCollectionsFile.swift

@@ -158,7 +158,7 @@ let syntaxCollectionsFile = SourceFileSyntax(leadingTrivia: copyrightHeader) {
         /// that the `SyntaxData` is of the correct kind. If it is not, the behaviour
         /// is undefined.
         internal init(_ data: SyntaxData) {
-          assert(data.raw.kind == .\(raw: node.swiftSyntaxKind))
+          precondition(data.raw.kind == .\(raw: node.swiftSyntaxKind))
           self._syntaxNode = Syntax(data)
         }
         """

CodeGeneration/Sources/generate-swiftsyntax/templates/swiftsyntax/SyntaxNodeFile.swift

@@ -59,7 +59,7 @@ func syntaxNode(emitKind: String) -> SourceFileSyntax {
           /// that the `SyntaxData` is of the correct kind. If it is not, the behaviour
           /// is undefined.
           internal init(_ data: SyntaxData) {
-            assert(data.raw.kind == .\(raw: node.swiftSyntaxKind))
+            precondition(data.raw.kind == .\(raw: node.swiftSyntaxKind))
             self._syntaxNode = Syntax(data)
           }
           """

CodeGeneration/Sources/generate-swiftsyntax/templates/swiftsyntax/SyntaxRewriterFile.swift

@@ -320,7 +320,7 @@ let syntaxRewriterFile = SourceFileSyntax(leadingTrivia: copyrightHeader) {
           // A child node was rewritten. Build the updated node.
 
           // Sanity check, ensure the new children are the same length.
-          assert(newLayout.count == node.raw.layoutView!.children.count)
+          precondition(newLayout.count == node.raw.layoutView!.children.count)
 
           let arena = SyntaxArena()
           let newRaw = node.raw.layoutView!.replacingLayout(with: Array(newLayout), arena: arena)

CodeGeneration/Sources/generate-swiftsyntax/templates/swiftsyntax/TokenKindFile.swift

@@ -282,7 +282,7 @@ let tokenKindFile = SourceFileSyntax(leadingTrivia: copyrightHeader) {
             }
           } else if token.text != nil {
             SwitchCaseSyntax("case .\(raw: token.swiftKind):") {
-              ExprSyntax("assert(text.isEmpty || rawKind.defaultText.map(String.init) == text)")
+              ExprSyntax("precondition(text.isEmpty || rawKind.defaultText.map(String.init) == text)")
               StmtSyntax("return .\(raw: token.swiftKind)")
             }
           } else {

Sources/IDEUtils/SyntaxClassifier.swift

@@ -189,7 +189,7 @@ private struct ClassificationVisitor {
       byteOffset += piece.byteLength
     }
 
-    assert(byteOffset == descriptor.byteOffset + descriptor.node.byteLength)
+    precondition(byteOffset == descriptor.byteOffset + descriptor.node.byteLength)
     return .continue
   }
 

Sources/SwiftCompilerPlugin/CompilerPlugin.swift

@@ -179,7 +179,7 @@ internal struct PluginHostConnection: MessageConnection {
     // Write the header (a 64-bit length field in little endian byte order).
     var count = UInt64(payload.count).littleEndian
     let header = Swift.withUnsafeBytes(of: &count) { Data($0) }
-    assert(header.count == 8)
+    precondition(header.count == 8)
 
     // Write the header and payload.
     try outputStream._write(contentsOf: header)

Sources/SwiftCompilerPluginMessageHandling/PluginMacroExpansionContext.swift

@@ -127,7 +127,7 @@ class SourceManager {
     }
     let localStartPosition = node.position(at: startKind)
     let localEndPosition = node.position(at: endKind)
-    assert(localStartPosition <= localEndPosition)
+    precondition(localStartPosition <= localEndPosition)
 
     let positionOffset = base.location.offset
 

Sources/SwiftDiagnostics/Diagnostic.swift

@@ -80,7 +80,7 @@ public struct DiagnosticsError: Error {
   public init(diagnostics: [Diagnostic]) {
     self.diagnostics = diagnostics
 
-    assert(
+    precondition(
       diagnostics.contains(where: { $0.diagMessage.severity == .error }),
       "at least one diagnostic must have severity == .error"
     )

Sources/SwiftDiagnostics/DiagnosticsFormatter.swift

@@ -29,7 +29,7 @@ extension Sequence where Element == Range<Int> {
       }
 
       // If the ranges overlap, expand the prior range.
-      assert(priorRange.lowerBound <= range.lowerBound)
+      precondition(priorRange.lowerBound <= range.lowerBound)
       if priorRange.overlaps(range) {
         let lower = priorRange.lowerBound
         let upper = Swift.max(priorRange.upperBound, range.upperBound)

Sources/SwiftDiagnostics/FixIt.swift

@@ -57,7 +57,7 @@ public struct FixIt {
   public let changes: Changes
 
   public init(message: FixItMessage, changes: Changes) {
-    assert(!changes.changes.isEmpty, "A Fix-It must have at least one change associated with it")
+    precondition(!changes.changes.isEmpty, "A Fix-It must have at least one change associated with it")
     self.message = message
     self.changes = changes
   }

Sources/SwiftParser/Declarations.swift

@@ -464,7 +464,7 @@ extension Parser {
       )
     }
 
-    assert(self.currentToken.starts(with: "<"))
+    precondition(self.currentToken.starts(with: "<"))
     let langle = self.consumeAnyToken(remapping: .leftAngle)
     var elements = [RawGenericParameterSyntax]()
     do {

Sources/SwiftParser/Expressions.swift

@@ -192,7 +192,7 @@ extension Parser {
       return lastElement
     }
 
-    assert(
+    precondition(
       elements.count.isMultiple(of: 2),
       "elements must have a even number of elements"
     )
@@ -619,7 +619,7 @@ extension Parser {
     declNameArgs: RawDeclNameArgumentsSyntax?,
     generics: RawGenericArgumentClauseSyntax?
   ) {
-    assert(self.at(.period))
+    precondition(self.at(.period))
     let (unexpectedPeriod, period, skipMemberName) = self.consumeMemberPeriod(previousNode: previousNode)
     if skipMemberName {
       let missingIdentifier = missingToken(.identifier)
@@ -685,7 +685,7 @@ extension Parser {
     _ flavor: ExprFlavor,
     forDirective: Bool
   ) -> RawExprSyntax {
-    assert(self.at(.poundIfKeyword))
+    precondition(self.at(.poundIfKeyword))
 
     let config = self.parsePoundIfDirective { (parser, isFirstElement) -> RawExprSyntax? in
       if !isFirstElement {
@@ -978,7 +978,7 @@ extension Parser {
       if self.currentToken.starts(with: "!") {
         questionOrExclaim = self.consumePrefix("!", as: .exclamationMark)
       } else {
-        assert(self.currentToken.starts(with: "?"))
+        precondition(self.currentToken.starts(with: "?"))
         questionOrExclaim = self.consumePrefix("?", as: .postfixQuestionMark)
       }
 
@@ -1044,7 +1044,7 @@ extension Parser {
           period = nil
         }
 
-        assert(self.at(.leftSquareBracket))
+        precondition(self.at(.leftSquareBracket))
         let lsquare = self.consumeAnyToken()
         let args: [RawTupleExprElementSyntax]
         if self.at(.rightSquareBracket) {
@@ -2085,7 +2085,7 @@ extension Parser.Lookahead {
   /// handle this by doing some lookahead in common situations. And later, Sema
   /// will emit a diagnostic with a fixit to add wrapping parens.
   mutating func isValidTrailingClosure(_ flavor: Parser.ExprFlavor) -> Bool {
-    assert(self.at(.leftBrace), "Couldn't be a trailing closure")
+    precondition(self.at(.leftBrace), "Couldn't be a trailing closure")
 
     // If this is the start of a get/set accessor, then it isn't a trailing
     // closure.
@@ -2270,7 +2270,7 @@ extension Parser {
               { (parser, _) in parser.parseSwitchCases(allowStandaloneStmtRecovery: allowStandaloneStmtRecovery) },
               syntax: { parser, cases in
                 guard cases.count == 1, let firstCase = cases.first else {
-                  assert(cases.isEmpty)
+                  precondition(cases.isEmpty)
                   return .switchCases(RawSwitchCaseListSyntax(elements: [], arena: parser.arena))
                 }
                 return .switchCases(firstCase)