[ASTGen] Generate Swift key-path expressions

Author: rintaro

include/swift/AST/ASTBridging.h

@@ -1335,6 +1335,18 @@ BridgedIsExpr BridgedIsExpr_createParsed(BridgedASTContext cContext,
                                          BridgedSourceLoc cIsLoc,
                                          BridgedTypeRepr cType);
 
+SWIFT_NAME("BridgedKeyPathDotExpr.createParsed(_:loc:)")
+BridgedKeyPathDotExpr
+BridgedKeyPathDotExpr_createParsed(BridgedASTContext cContext,
+                                   BridgedSourceLoc cLoc);
+
+SWIFT_NAME("BridgedKeyPathExpr.createParsed(_:backslashLoc:parsedRoot:"
+           "parsedPath:hasLeadingDot:)")
+BridgedKeyPathExpr BridgedKeyPathExpr_createParsed(
+    BridgedASTContext cContext, BridgedSourceLoc cBackslashLoc,
+    BridgedNullableExpr cParsedRoot, BridgedNullableExpr cParsedPath,
+    bool hasLeadingDot);
+
 SWIFT_NAME("BridgedMacroExpansionExpr.createParsed(_:poundLoc:macroNameRef:"
            "macroNameLoc:leftAngleLoc:genericArgs:rightAngleLoc:args:)")
 BridgedMacroExpansionExpr BridgedMacroExpansionExpr_createParsed(

lib/AST/Bridging/DeclBridging.cpp

@@ -346,6 +346,8 @@ static void setParsedMembers(IterableDeclContext *IDC,
     }
   }
 
+  IDC->setMaybeHasOperatorDeclarations();
+  IDC->setMaybeHasNestedClassDeclarations();
   ctx.evaluator.cacheOutput(
       ParseMembersRequest{IDC},
       FingerprintAndMembers{std::nullopt, ctx.AllocateCopy(members)});

lib/AST/Bridging/ExprBridging.cpp

@@ -281,6 +281,21 @@ BridgedIntegerLiteralExpr_createParsed(BridgedASTContext cContext,
       IntegerLiteralExpr(cStr.unbridged(), cTokenLoc.unbridged());
 }
 
+BridgedKeyPathDotExpr
+BridgedKeyPathDotExpr_createParsed(BridgedASTContext cContext,
+                                   BridgedSourceLoc cLoc) {
+  return new (cContext.unbridged()) KeyPathDotExpr(cLoc.unbridged());
+}
+
+BridgedKeyPathExpr BridgedKeyPathExpr_createParsed(
+    BridgedASTContext cContext, BridgedSourceLoc cBackslashLoc,
+    BridgedNullableExpr cParsedRoot, BridgedNullableExpr cParsedPath,
+    bool hasLeadingDot) {
+  return KeyPathExpr::createParsed(
+      cContext.unbridged(), cBackslashLoc.unbridged(), cParsedRoot.unbridged(),
+      cParsedPath.unbridged(), hasLeadingDot);
+}
+
 BridgedSuperRefExpr
 BridgedSuperRefExpr_createParsed(BridgedASTContext cContext,
                                  BridgedSourceLoc cSuperLoc) {

lib/ASTGen/Sources/ASTGen/Decls.swift

@@ -349,7 +349,13 @@ extension ASTGenVisitor {
     accessorDecl node: AccessorDeclSyntax,
     for storage: BridgedAbstractStorageDecl
   ) -> BridgedAccessorDecl? {
-    // TODO: Attributes and modifier.
+    // FIXME: Attributes.
+    var attrs = BridgedDeclAttributes()
+    if
+      let modifier = node.modifier,
+      let attr = self.generate(declModifier: modifier) {
+      attrs.add(attr)
+    }
 
     guard let kind = self.generate(accessorSpecifier: node.accessorSpecifier) else {
       // TODO: We could potentially recover if this is the first accessor by treating
@@ -368,6 +374,7 @@ extension ASTGenVisitor {
       throwsSpecifierLoc: self.generateSourceLoc(node.effectSpecifiers?.throwsClause),
       thrownType: self.generate(type: node.effectSpecifiers?.thrownError)
     )
+    accessor.asDecl.setAttrs(attrs)
     if let body = node.body {
       self.withDeclContext(accessor.asDeclContext) {
         accessor.setParsedBody(self.generate(codeBlock: body))

lib/ASTGen/Sources/ASTGen/Exprs.swift

@@ -46,18 +46,14 @@ func isExprMigrated(_ node: ExprSyntax) -> Bool {
       .discardAssignmentExpr, .declReferenceExpr, .dictionaryExpr, .doExpr,
       .editorPlaceholderExpr, .floatLiteralExpr, .forceUnwrapExpr, .functionCallExpr,
       .genericSpecializationExpr, .ifExpr, .infixOperatorExpr, .inOutExpr,
-      .integerLiteralExpr, .isExpr, .macroExpansionExpr, .memberAccessExpr, .nilLiteralExpr,
+      .integerLiteralExpr, .isExpr, .keyPathExpr, .macroExpansionExpr, .memberAccessExpr, .nilLiteralExpr,
       .optionalChainingExpr, .packElementExpr, .packExpansionExpr, .patternExpr, .postfixIfConfigExpr,
       .postfixOperatorExpr, .prefixOperatorExpr, .regexLiteralExpr, .sequenceExpr,
       .simpleStringLiteralExpr, .subscriptCallExpr, .stringLiteralExpr, .superExpr,
       .switchExpr, .tryExpr, .tupleExpr, .typeExpr, .unresolvedAsExpr, .unresolvedIsExpr,
       .unresolvedTernaryExpr, .ternaryExpr:
       break
 
-    // Known unimplemented kinds.
-    case .keyPathExpr:
-      return false
-
     // Unknown expr kinds.
     case _ where current.is(ExprSyntax.self):
       return false
@@ -129,8 +125,8 @@ extension ASTGenVisitor {
       return self.generate(integerLiteralExpr: node).asExpr
     case .isExpr:
       preconditionFailure("IsExprSyntax only appear after operator folding")
-    case .keyPathExpr:
-      break
+    case .keyPathExpr(let node):
+      return self.generate(keyPathExpr: node)
     case .macroExpansionExpr(let node):
       return self.generate(macroExpansionExpr: node).asExpr
     case .memberAccessExpr(let node):
@@ -535,6 +531,118 @@ extension ASTGenVisitor {
     )
   }
 
+  func generate(keyPathComponent node: KeyPathComponentSyntax, baseExpr: BridgedExpr) -> BridgedExpr {
+    switch node.component {
+    case .property(let prop):
+      let dotLoc = self.generateSourceLoc(node.period)
+      if prop.declName.baseName.presence == .missing {
+        return BridgedErrorExpr.create(
+          self.ctx,
+          loc: BridgedSourceRange(start: dotLoc, end: dotLoc)
+        ).asExpr
+      } else if prop.declName.baseName.keywordKind == .`self` {
+        // TODO: Diagnose if there's arguments
+        assert(prop.declName.argumentNames == nil)
+
+        return BridgedDotSelfExpr.createParsed(
+          self.ctx,
+          subExpr: baseExpr,
+          dotLoc: dotLoc,
+          selfLoc: self.generateSourceLoc(prop.declName)
+        ).asExpr
+      } else {
+        let declNameRef = self.generateDeclNameRef(declReferenceExpr: prop.declName)
+        return BridgedUnresolvedDotExpr.createParsed(
+          self.ctx,
+          base: baseExpr,
+          dotLoc: dotLoc,
+          name: declNameRef.name,
+          nameLoc: declNameRef.loc
+        ).asExpr
+      }
+
+    case .optional(let comp):
+      if comp.questionOrExclamationMark.rawText == "!" {
+        return BridgedForceValueExpr.createParsed(
+          self.ctx,
+          subExpr: baseExpr,
+          exclaimLoc: self.generateSourceLoc(comp.questionOrExclamationMark)
+        ).asExpr
+      } else {
+        return BridgedBindOptionalExpr.createParsed(
+          self.ctx,
+          subExpr: baseExpr,
+          questionLoc: self.generateSourceLoc(comp.questionOrExclamationMark)
+        ).asExpr
+      }
+
+    case .subscript(let comp):
+      return BridgedSubscriptExpr.createParsed(
+        self.ctx,
+        baseExpr: baseExpr,
+        args: self.generateArgumentList(
+          leftParen: comp.leftSquare,
+          labeledExprList: comp.arguments,
+          rightParen: comp.rightSquare,
+          trailingClosure: nil,
+          additionalTrailingClosures: nil
+        )
+      ).asExpr
+    }
+  }
+
+  func generate(keyPathExpr node: KeyPathExprSyntax) -> BridgedExpr {
+    guard !node.components.isEmpty else {
+      // FIXME: Diagnostics KeyPath expression without any component.
+      return BridgedErrorExpr.create(self.ctx, loc: self.generateSourceRange(node)).asExpr
+    }
+
+    var rootExpr: BridgedExpr?
+    if let parsedType = node.root, !parsedType.is(MissingTypeSyntax.self) {
+      let rootType = self.generate(type: parsedType)
+      rootExpr = BridgedTypeExpr.createParsed(self.ctx, type: rootType).asExpr
+    } else {
+      rootExpr = nil
+    }
+
+    var inRoot = rootExpr != nil
+    var pathExpr: BridgedExpr? = nil
+
+    for component in node.components {
+      if inRoot {
+        switch component.component {
+        case // "root" expression is separated by '.?' or '.[idx]'
+          .optional(_) where component.period != nil,
+          .subscript(_) where component.period != nil:
+          inRoot = false
+        default:
+          rootExpr = self.generate(keyPathComponent: component, baseExpr: rootExpr!)
+          continue
+        }
+      }
+
+      if pathExpr == nil {
+        // 'KeyPathDotExpr' is a dummy base expression.
+        pathExpr = BridgedKeyPathDotExpr.createParsed(
+          self.ctx,
+          // Use 'component' instead of 'component.period' because period can
+          // be nil (e.g. '\?'), but 'loc' must be a valid location.
+          loc: self.generateSourceLoc(component)
+        ).asExpr
+      }
+
+      pathExpr = self.generate(keyPathComponent: component, baseExpr: pathExpr!)
+    }
+
+    return BridgedKeyPathExpr.createParsed(
+      self.ctx,
+      backslashLoc: self.generateSourceLoc(node.backslash),
+      parsedRoot: rootExpr.asNullable,
+      parsedPath: pathExpr.asNullable,
+      hasLeadingDot: rootExpr == nil
+    ).asExpr
+  }
+
   struct FreestandingMacroExpansionInfo {
     var poundLoc: BridgedSourceLoc
     var macroNameRef: BridgedDeclNameRef