[ASTGen] Generate interpolated string literal

Author: rintaro

include/swift/AST/ASTBridging.h

@@ -126,10 +126,12 @@ BridgedDeclNameRef
 BridgedDeclNameRef_createParsed(BridgedDeclBaseName cBaseName);
 
 class BridgedDeclNameLoc {
-  const void *_Nonnull LocationInfo;
+  const void *_Nullable LocationInfo;
   size_t NumArgumentLabels;
 
 public:
+  BridgedDeclNameLoc() : LocationInfo(nullptr), NumArgumentLabels(0) {}
+
 #ifdef USED_IN_CPP_SOURCE
   BridgedDeclNameLoc(swift::DeclNameLoc loc)
       : LocationInfo(loc.LocationInfo),
@@ -1025,6 +1027,10 @@ BridgedSubscriptDecl_asAbstractStorageDecl(BridgedSubscriptDecl decl);
 // MARK: VarDecl
 //===----------------------------------------------------------------------===//
 
+SWIFT_NAME("BridgedVarDecl.createImplicitStringInterpolationVar(_:)")
+BridgedVarDecl BridgedVarDec_createImplicitStringInterpolationVar(
+    BridgedDeclContext cDeclContext);
+
 SWIFT_NAME("BridgedVarDecl.getSourceLocation(self:)")
 BRIDGED_INLINE BridgedSourceLoc BridgedVarDecl_getSourceLocation(BridgedVarDecl decl);
 
@@ -1054,6 +1060,11 @@ struct BridgedCallArgument {
 #endif
 };
 
+SWIFT_NAME("BridgedArgumentList.createImplicitUnlabeled(_:exprs:)")
+BridgedArgumentList
+BridgedArgumentList_createImplicitUnlabeled(BridgedASTContext cContext,
+                                            BridgedArrayRef cExprs);
+
 SWIFT_NAME("BridgedArgumentList.createParsed(_:lParenLoc:args:rParenLoc:"
            "firstTrailingClosureIndex:)")
 BridgedArgumentList BridgedArgumentList_createParsed(
@@ -1129,6 +1140,12 @@ BridgedCopyExpr BridgedCopyExpr_createParsed(BridgedASTContext cContext,
                                              BridgedSourceLoc cCopyLoc,
                                              BridgedExpr cSubExpr);
 
+SWIFT_NAME("BridgedDeclRefExpr.create(_:decl:loc:isImplicit:)")
+BridgedDeclRefExpr BridgedDeclRefExpr_create(BridgedASTContext cContext,
+                                             BridgedDecl cDecl,
+                                             BridgedDeclNameLoc cLoc,
+                                             bool IsImplicit);
+
 SWIFT_NAME("BridgedDictionaryExpr.createParsed(_:lBracketLoc:elements:"
            "colonLocs:rBracketLoc:)")
 BridgedDictionaryExpr BridgedDictionaryExpr_createParsed(
@@ -1165,6 +1182,13 @@ BridgedIntegerLiteralExpr_createParsed(BridgedASTContext cContext,
                                        BridgedStringRef cStr,
                                        BridgedSourceLoc cTokenLoc);
 
+SWIFT_NAME("BridgedInterpolatedStringLiteralExpr.createParsed(_:loc:"
+           "literalCapacity:interpolationCount:appendingExpr:)")
+BridgedInterpolatedStringLiteralExpr
+BridgedInterpolatedStringLiteralExpr_createParsed(
+    BridgedASTContext cContext, BridgedSourceLoc cLoc, size_t literalCapacity,
+    size_t interpolationCount, BridgedTapExpr cAppendingExpr);
+
 SWIFT_NAME("BridgedIsExpr.createParsed(_:isLoc:type:)")
 BridgedIsExpr BridgedIsExpr_createParsed(BridgedASTContext cContext,
                                          BridgedSourceLoc cIsLoc,
@@ -1218,6 +1242,10 @@ BridgedStringLiteralExpr_createParsed(BridgedASTContext cContext,
                                       BridgedStringRef cStr,
                                       BridgedSourceLoc cTokenLoc);
 
+SWIFT_NAME("BridgedTapExpr.create(_:body:)")
+BridgedTapExpr BridgedTapExpr_create(BridgedASTContext cContext,
+                                     BridgedBraceStmt cBody);
+
 SWIFT_NAME("BridgedTernaryExpr.createParsed(_:questionLoc:thenExpr:colonLoc:)")
 BridgedTernaryExpr BridgedTernaryExpr_createParsed(
     BridgedASTContext cContext, BridgedSourceLoc cQuestionLoc,

include/swift/AST/Decl.h

@@ -6465,6 +6465,8 @@ class VarDecl : public AbstractStorageDecl {
 
   clang::PointerAuthQualifier getPointerAuthQualifier() const;
 
+  static VarDecl *createImplicitStringInterpolationVar(DeclContext *DC);
+
   // Implement isa/cast/dyncast/etc.
   static bool classof(const Decl *D) { 
     return D->getKind() == DeclKind::Var || D->getKind() == DeclKind::Param; 

lib/AST/ASTBridging.cpp

@@ -1321,6 +1321,12 @@ BridgedTopLevelCodeDecl BridgedTopLevelCodeDecl_createExpr(
   return new (context) TopLevelCodeDecl(declContext, Brace);
 }
 
+BridgedVarDecl BridgedVarDec_createImplicitStringInterpolationVar(
+    BridgedDeclContext cDeclContext) {
+  return VarDecl::createImplicitStringInterpolationVar(
+      cDeclContext.unbridged());
+}
+
 //===----------------------------------------------------------------------===//
 // MARK: AbstractStorageDecl
 //===----------------------------------------------------------------------===//
@@ -1359,6 +1365,13 @@ bool BridgedNominalTypeDecl_isStructWithUnreferenceableStorage(
 // MARK: Exprs
 //===----------------------------------------------------------------------===//
 
+BridgedArgumentList
+BridgedArgumentList_createImplicitUnlabeled(BridgedASTContext cContext,
+                                            BridgedArrayRef cExprs) {
+  return ArgumentList::forImplicitUnlabeled(cContext.unbridged(),
+                                            cExprs.unbridged<Expr *>());
+}
+
 BridgedArgumentList BridgedArgumentList_createParsed(
     BridgedASTContext cContext, BridgedSourceLoc cLParenLoc,
     BridgedArrayRef cArgs, BridgedSourceLoc cRParenLoc,
@@ -1485,6 +1498,14 @@ BridgedCopyExpr BridgedCopyExpr_createParsed(BridgedASTContext cContext,
       CopyExpr(cCopyLoc.unbridged(), cSubExpr.unbridged());
 }
 
+BridgedDeclRefExpr BridgedDeclRefExpr_create(BridgedASTContext cContext,
+                                             BridgedDecl cDecl,
+                                             BridgedDeclNameLoc cLoc,
+                                             bool IsImplicit) {
+  return new (cContext.unbridged()) DeclRefExpr(
+      cast<ValueDecl>(cDecl.unbridged()), cLoc.unbridged(), IsImplicit);
+}
+
 BridgedDictionaryExpr BridgedDictionaryExpr_createParsed(
     BridgedASTContext cContext, BridgedSourceLoc cLBracketLoc,
     BridgedArrayRef cElements, BridgedArrayRef cCommaLocs,
@@ -1536,6 +1557,15 @@ BridgedIntegerLiteralExpr_createParsed(BridgedASTContext cContext,
   return new (context) IntegerLiteralExpr(str, cTokenLoc.unbridged());
 }
 
+BridgedInterpolatedStringLiteralExpr
+BridgedInterpolatedStringLiteralExpr_createParsed(
+    BridgedASTContext cContext, BridgedSourceLoc cLoc, size_t literalCapacity,
+    size_t interpolationCount, BridgedTapExpr cAppendingExpr) {
+  return new (cContext.unbridged()) InterpolatedStringLiteralExpr(
+      cLoc.unbridged(), literalCapacity, interpolationCount,
+      cAppendingExpr.unbridged());
+}
+
 BridgedIsExpr BridgedIsExpr_createParsed(BridgedASTContext cContext,
                                          BridgedSourceLoc cIsLoc,
                                          BridgedTypeRepr cType) {
@@ -1610,6 +1640,11 @@ BridgedStringLiteralExpr_createParsed(BridgedASTContext cContext,
   return new (context) StringLiteralExpr(str, cTokenLoc.unbridged());
 }
 
+BridgedTapExpr BridgedTapExpr_create(BridgedASTContext cContext,
+                                     BridgedBraceStmt cBody) {
+  return new (cContext.unbridged()) TapExpr(nullptr, cBody.unbridged());
+}
+
 BridgedTernaryExpr BridgedTernaryExpr_createParsed(
     BridgedASTContext cContext, BridgedSourceLoc cQuestionLoc,
     BridgedExpr cThenExpr, BridgedSourceLoc cColonLoc) {

lib/AST/Decl.cpp

@@ -7903,6 +7903,17 @@ bool VarDecl::isOrdinaryStoredProperty() const {
   return hasStorage() && !hasObservers();
 }
 
+VarDecl *VarDecl::createImplicitStringInterpolationVar(DeclContext *DC) {
+  // Make the variable which will contain our temporary value.
+  ASTContext &C = DC->getASTContext();
+  auto var =
+      new (C) VarDecl(/*IsStatic=*/false, VarDecl::Introducer::Var,
+                      /*NameLoc=*/SourceLoc(), C.Id_dollarInterpolation, DC);
+  var->setImplicit(true);
+  var->setUserAccessible(false);
+  return var;
+}
+
 void ParamDecl::setSpecifier(Specifier specifier) {
   VarDecl::Introducer introducer;
   switch (specifier) {

lib/ASTGen/Sources/ASTGen/Exprs.swift

@@ -48,15 +48,6 @@ func isExprMigrated(_ node: ExprSyntax) -> Bool {
       .postfixOperatorExpr, .prefixOperatorExpr, .sequenceExpr,
       .stringLiteralExpr, .tryExpr, .tupleExpr, .typeExpr, .unresolvedAsExpr,
       .unresolvedIsExpr, .unresolvedTernaryExpr:
-
-      // `generate(stringLiteralExpr:)` doesn't support interpolations.
-      if let str = current.as(StringLiteralExprSyntax.self) {
-        if str.segments.count != 1 {
-          return false
-        }
-        assert(str.segments.first!.is(StringSegmentSyntax.self))
-      }
-
       break
 
     // Known unimplemented kinds.
@@ -176,7 +167,7 @@ extension ASTGenVisitor {
     case .simpleStringLiteralExpr:
       break
     case .stringLiteralExpr(let node):
-      return self.generate(stringLiteralExpr: node).asExpr
+      return self.generate(stringLiteralExpr: node)
     case .subscriptCallExpr:
       break
     case .superExpr: