Merge pull request swiftlang#70467 from AnthonyLatsis/recursive-member-typerepr

AST: Remodel `MemberTypeRepr` to be recursive

Author: slavapestov

include/swift/AST/ASTBridging.h

@@ -1589,11 +1589,11 @@ BridgedInverseTypeRepr_createParsed(BridgedASTContext cContext,
                                     BridgedSourceLoc cTildeLoc,
                                     BridgedTypeRepr cConstraint);
 
-SWIFT_NAME("BridgedMemberTypeRepr.createParsed(_:base:members:)")
-BridgedTypeRepr
-BridgedMemberTypeRepr_createParsed(BridgedASTContext cContext,
-                                   BridgedTypeRepr baseComponent,
-                                   BridgedArrayRef bridgedMemberComponents);
+SWIFT_NAME("BridgedDeclRefTypeRepr.createParsed(_:base:name:nameLoc:genericArguments:angleRange:)")
+BridgedDeclRefTypeRepr BridgedDeclRefTypeRepr_createParsed(
+    BridgedASTContext cContext, BridgedTypeRepr cBase, BridgedIdentifier cName,
+    BridgedSourceLoc cLoc, BridgedArrayRef cGenericArguments,
+    BridgedSourceRange cAngleRange);
 
 SWIFT_NAME("BridgedMetatypeTypeRepr.createParsed(_:base:typeKeywordLoc:)")
 BridgedMetatypeTypeRepr

include/swift/AST/ASTWalker.h

@@ -103,6 +103,37 @@ enum class MacroWalking {
   None
 };
 
+/// A scheme for walking a `MemberTypeRepr`.
+enum class MemberTypeReprWalkingScheme {
+  /// Walk in source order, such that each subsequent dot-separated component is
+  /// a child of the previous one. For example, walk `A.B<T.U>.C` like so
+  /// (top-down order):
+  ///
+  /// ```
+  /// A
+  /// ╰─B
+  ///   ├─T
+  ///   │ ╰─U
+  ///   ╰─C
+  /// ```
+  SourceOrderRecursive,
+
+  /// Walk in AST order (that is, according to how member type
+  /// representations are modeled in the AST, such that each previous
+  /// dot-separated component is a child of the subsequent one), base before
+  /// generic arguments. For example, walk `A.B<T.U>.C` like so
+  /// (top-down order):
+  ///
+  /// ```
+  /// C
+  /// ╰─B
+  ///   ├─A
+  ///   ╰─U
+  ///     ╰─T
+  /// ```
+  ASTOrderRecursive
+};
+
 /// An abstract class used to traverse an AST.
 class ASTWalker {
 public:
@@ -563,6 +594,11 @@ class ASTWalker {
     return Action::Continue();
   }
 
+  /// This method configures how to walk `MemberTypeRepr` nodes.
+  virtual MemberTypeReprWalkingScheme getMemberTypeReprWalkingScheme() const {
+    return MemberTypeReprWalkingScheme::ASTOrderRecursive;
+  }
+
   /// This method configures whether the walker should explore into the generic
   /// params in AbstractFunctionDecl and NominalTypeDecl.
   virtual bool shouldWalkIntoGenericParams() { return false; }

include/swift/AST/Attr.h

@@ -54,6 +54,7 @@ class ASTContext;
 struct PrintOptions;
 class CustomAttr;
 class Decl;
+class DeclRefTypeRepr;
 class AbstractFunctionDecl;
 class FuncDecl;
 class ClassDecl;
@@ -1766,7 +1767,7 @@ class CustomAttr final : public DeclAttribute {
   ///
   /// For an identifier type repr, return a pair of `nullptr` and the
   /// identifier.
-  std::pair<IdentTypeRepr *, IdentTypeRepr *> destructureMacroRef();
+  std::pair<IdentTypeRepr *, DeclRefTypeRepr *> destructureMacroRef();
 
   /// Whether the attribute has any arguments.
   bool hasArgs() const { return argList != nullptr; }

include/swift/AST/TypeDeclFinder.h

@@ -19,7 +19,7 @@
 namespace swift {
 
 class BoundGenericType;
-class IdentTypeRepr;
+class DeclRefTypeRepr;
 class NominalType;
 class TypeAliasType;
 
@@ -57,15 +57,13 @@ class SimpleTypeDeclFinder : public TypeDeclFinder {
     : Callback(callback) {}
 };
 
-/// Walks a \c TypeRepr to find all \c IdentTypeRepr nodes with bound
-/// type declarations.
-///
-/// Subclasses can either override #visitTypeDecl if they only care about
-/// types on their own, or #visitIdentTypeRepr if they want to keep
-/// the TypeRepr around.
-class TypeReprIdentFinder : public ASTWalker {
-  /// The function to call when a \c IdentTypeRepr is seen.
-  llvm::function_ref<bool(const IdentTypeRepr *)> Callback;
+/// Walks a `TypeRepr` and reports all `DeclRefTypeRepr` nodes with bound
+/// type declarations by invoking a given callback. These nodes are reported in
+/// depth- and base-first AST order. For example, nodes in `A<T>.B<U>` will be
+/// reported in the following order: `TAUB`.
+class DeclRefTypeReprFinder : public ASTWalker {
+  /// The function to call when a `DeclRefTypeRepr` is seen.
+  llvm::function_ref<bool(const DeclRefTypeRepr *)> Callback;
 
   MacroWalking getMacroWalkingBehavior() const override {
     return MacroWalking::Arguments;
@@ -74,11 +72,10 @@ class TypeReprIdentFinder : public ASTWalker {
   PostWalkAction walkToTypeReprPost(TypeRepr *TR) override;
 
 public:
-  explicit TypeReprIdentFinder(
-      llvm::function_ref<bool(const IdentTypeRepr *)> callback)
-    : Callback(callback) {}
+  explicit DeclRefTypeReprFinder(
+      llvm::function_ref<bool(const DeclRefTypeRepr *)> callback)
+      : Callback(callback) {}
 };
-
 }
 
 #endif