ASTGen: Translate default arguments

Author: AnthonyLatsis

include/swift/AST/CASTBridging.h

@@ -289,6 +289,9 @@ void *IntegerLiteralExpr_create(BridgedASTContext cContext, BridgedString cStr,
 void *BooleanLiteralExpr_create(BridgedASTContext cContext, _Bool value,
                                 BridgedSourceLoc cTokenLoc);
 
+void *NilLiteralExpr_create(BridgedASTContext cContext,
+                            BridgedSourceLoc cNilKeywordLoc);
+
 void *ArrayExpr_create(BridgedASTContext cContext, BridgedSourceLoc cLLoc,
                        BridgedArrayRef elements, BridgedArrayRef commas,
                        BridgedSourceLoc cRLoc);
@@ -315,7 +318,8 @@ void *
 ParamDecl_create(BridgedASTContext cContext, BridgedDeclContext cDeclContext,
                  BridgedSourceLoc cSpecifierLoc, BridgedIdentifier cFirstName,
                  BridgedSourceLoc cFirstNameLoc, BridgedIdentifier cSecondName,
-                 BridgedSourceLoc cSecondNameLoc, void *_Nullable opaqueType);
+                 BridgedSourceLoc cSecondNameLoc, void *_Nullable opaqueType,
+                 void *_Nullable opaqueDefaultValue);
 
 struct BridgedFuncDecl
 FuncDecl_create(BridgedASTContext cContext, BridgedDeclContext cDeclContext,

include/swift/AST/DefaultArgumentKind.h

@@ -54,6 +54,11 @@ enum class DefaultArgumentKind : uint8_t {
 };
 enum { NumDefaultArgumentKindBits = 4 };
 
+/// Determine the kind of a default argument given a parsed expression that has
+/// not yet been type-checked.
+/// FIXME: Requestify/internalize the computation of the default arg expr and its kind (given a parsed expr) once the old parser no longer needs this.
+DefaultArgumentKind getDefaultArgKind(Expr *init);
+
 struct ArgumentAttrs {
   DefaultArgumentKind argumentKind;
   bool isUnavailableInSwift = false;

lib/AST/CASTBridging.cpp

@@ -11,6 +11,7 @@
 #include "swift/AST/ParseRequests.h"
 #include "swift/AST/Pattern.h"
 #include "swift/AST/PluginRegistry.h"
+#include "swift/AST/SourceFile.h"
 #include "swift/AST/Stmt.h"
 #include "swift/AST/TypeRepr.h"
 
@@ -319,6 +320,13 @@ void *BooleanLiteralExpr_create(BridgedASTContext cContext, bool value,
   return new (context) BooleanLiteralExpr(value, convertSourceLoc(cTokenLoc));
 }
 
+void *NilLiteralExpr_create(BridgedASTContext cContext,
+                            BridgedSourceLoc cNilKeywordLoc) {
+  Expr *e = new (convertASTContext(cContext))
+      NilLiteralExpr(convertSourceLoc(cNilKeywordLoc));
+  return e;
+}
+
 void *VarDecl_create(BridgedASTContext cContext,
                      BridgedDeclContext cDeclContext,
                      BridgedSourceLoc cBindingKeywordLoc, void *opaqueNameExpr,
@@ -402,20 +410,34 @@ void *
 ParamDecl_create(BridgedASTContext cContext, BridgedDeclContext cDeclContext,
                  BridgedSourceLoc cSpecifierLoc, BridgedIdentifier cFirstName,
                  BridgedSourceLoc cFirstNameLoc, BridgedIdentifier cSecondName,
-                 BridgedSourceLoc cSecondNameLoc, void *_Nullable opaqueType) {
+                 BridgedSourceLoc cSecondNameLoc, void *_Nullable opaqueType,
+                 void *_Nullable opaqueDefaultValue) {
   assert((bool)cSecondNameLoc.raw == (bool)cSecondName.raw);
   if (!cSecondName.raw) {
     cSecondName = cFirstName;
     cSecondNameLoc = cFirstNameLoc;
   }
 
-  ASTContext &context = convertASTContext(cContext);
+  auto *declContext = convertDeclContext(cDeclContext);
+
+  auto *defaultValue = static_cast<Expr *>(opaqueDefaultValue);
+  DefaultArgumentKind defaultArgumentKind;
+
+  if (declContext->getParentSourceFile()->Kind == SourceFileKind::Interface &&
+      isa<SuperRefExpr>(defaultValue)) {
+    defaultValue = nullptr;
+    defaultArgumentKind = DefaultArgumentKind::Inherited;
+  } else {
+    defaultArgumentKind = getDefaultArgKind(defaultValue);
+  }
 
-  auto *paramDecl = new (context) ParamDecl(
+  auto *paramDecl = new (convertASTContext(cContext)) ParamDecl(
       convertSourceLoc(cSpecifierLoc), convertSourceLoc(cFirstNameLoc),
       convertIdentifier(cFirstName), convertSourceLoc(cSecondNameLoc),
-      convertIdentifier(cSecondName), convertDeclContext(cDeclContext));
+      convertIdentifier(cSecondName), declContext);
   paramDecl->setTypeRepr(static_cast<TypeRepr *>(opaqueType));
+  paramDecl->setDefaultExpr(defaultValue, /*isTypeChecked*/ false);
+  paramDecl->setDefaultArgumentKind(defaultArgumentKind);
 
   return paramDecl;
 }

lib/AST/Decl.cpp

@@ -7897,6 +7897,30 @@ ParamDecl *ParamDecl::createImplicit(ASTContext &Context,
                                    interfaceType, Parent, specifier);
 }
 
+DefaultArgumentKind swift::getDefaultArgKind(Expr *init) {
+  if (!init)
+    return DefaultArgumentKind::None;
+
+  // Parse an as-written 'nil' expression as the special NilLiteral kind,
+  // which is emitted by the caller and can participate in rethrows
+  // checking.
+  if (isa<NilLiteralExpr>(init))
+    return DefaultArgumentKind::NilLiteral;
+
+  auto magic = dyn_cast<MagicIdentifierLiteralExpr>(init);
+  if (!magic)
+    return DefaultArgumentKind::Normal;
+
+  switch (magic->getKind()) {
+#define MAGIC_IDENTIFIER(NAME, STRING, SYNTAX_KIND)                            \
+  case MagicIdentifierLiteralExpr::NAME:                                       \
+    return DefaultArgumentKind::NAME;
+#include "swift/AST/MagicIdentifierKinds.def"
+  }
+
+  llvm_unreachable("Unhandled MagicIdentifierLiteralExpr in switch.");
+}
+
 /// Retrieve the type of 'self' for the given context.
 Type DeclContext::getSelfTypeInContext() const {
   return mapTypeIntoContext(getSelfInterfaceType());

lib/ASTGen/Sources/ASTGen/Literals.swift

@@ -47,4 +47,8 @@ extension ASTGenVisitor {
       )
     )
   }
+
+  func visit(_ node: NilLiteralExprSyntax) -> ASTNode {
+    .expr(NilLiteralExpr_create(self.ctx, self.bridgedSourceLoc(for: node.nilKeyword)))
+  }
 }

lib/ASTGen/Sources/ASTGen/ParameterClause.swift

@@ -41,7 +41,8 @@ extension ASTGenVisitor {
         self.bridgedSourceLoc(for: node.firstName),
         secondName,
         secondNameLoc,
-        self.visit(node.type).rawValue
+        self.visit(node.type).rawValue,
+        self.visit(node.defaultValue?.value)?.rawValue
       )
     )
   }

lib/Parse/ParsePattern.cpp

@@ -30,31 +30,6 @@
 
 using namespace swift;
 
-/// Determine the kind of a default argument given a parsed
-/// expression that has not yet been type-checked.
-static DefaultArgumentKind getDefaultArgKind(Expr *init) {
-  if (!init)
-    return DefaultArgumentKind::None;
-
-  // Parse an as-written 'nil' expression as the special NilLiteral kind,
-  // which is emitted by the caller and can participate in rethrows
-  // checking.
-  if (isa<NilLiteralExpr>(init))
-    return DefaultArgumentKind::NilLiteral;
-
-  auto magic = dyn_cast<MagicIdentifierLiteralExpr>(init);
-  if (!magic)
-    return DefaultArgumentKind::Normal;
-
-  switch (magic->getKind()) {
-#define MAGIC_IDENTIFIER(NAME, STRING, SYNTAX_KIND) \
-  case MagicIdentifierLiteralExpr::NAME: return DefaultArgumentKind::NAME;
-#include "swift/AST/MagicIdentifierKinds.def"
-  }
-
-  llvm_unreachable("Unhandled MagicIdentifierLiteralExpr in switch.");
-}
-
 void Parser::DefaultArgumentInfo::setFunctionContext(
     DeclContext *DC, ParameterList *paramList){
   for (auto context : ParsedContexts) {

test/ASTGen/verify-parse.swift

@@ -49,7 +49,7 @@ func test2(e b: Bool) {
     true
 }
 
-func test3(y: Int) -> Int {
+func test3(y: Int = 0, oi: Int? = nil) -> Int {
   let x =
     y
   return x