[AST] SwitchStmt only hold CaseStmt

rintaro · rintaro · commit 5eac58e1e018 · 2025-03-08T09:14:40.000-08:00
Now that there is no way SwitchStmt to hold AST nodes other than
CaseStmt.
diff --git a/include/swift/AST/Stmt.h b/include/swift/AST/Stmt.h
@@ -1408,7 +1408,7 @@ class CaseStmt final
 
 /// Switch statement.
 class SwitchStmt final : public LabeledStmt,
-    private llvm::TrailingObjects<SwitchStmt, ASTNode> {
+                         private llvm::TrailingObjects<SwitchStmt, CaseStmt *> {
   friend TrailingObjects;
 
   SourceLoc SwitchLoc, LBraceLoc, RBraceLoc;
@@ -1431,16 +1431,13 @@ class SwitchStmt final : public LabeledStmt,
 public:
   /// Allocate a new SwitchStmt in the given ASTContext.
   static SwitchStmt *create(LabeledStmtInfo LabelInfo, SourceLoc SwitchLoc,
-                            Expr *SubjectExpr,
-                            SourceLoc LBraceLoc,
-                            ArrayRef<ASTNode> Cases,
-                            SourceLoc RBraceLoc,
-                            SourceLoc EndLoc,
-                            ASTContext &C);
+                            Expr *SubjectExpr, SourceLoc LBraceLoc,
+                            ArrayRef<CaseStmt *> Cases, SourceLoc RBraceLoc,
+                            SourceLoc EndLoc, ASTContext &C);
 
   static SwitchStmt *createImplicit(LabeledStmtInfo LabelInfo,
-                                    Expr *SubjectExpr, ArrayRef<ASTNode> Cases,
-                                    ASTContext &C) {
+                                    Expr *SubjectExpr,
+                                    ArrayRef<CaseStmt *> Cases, ASTContext &C) {
     return SwitchStmt::create(LabelInfo, /*SwitchLoc=*/SourceLoc(), SubjectExpr,
                               /*LBraceLoc=*/SourceLoc(), Cases,
                               /*RBraceLoc=*/SourceLoc(), /*EndLoc=*/SourceLoc(),
@@ -1463,27 +1460,10 @@ class SwitchStmt final : public LabeledStmt,
   Expr *getSubjectExpr() const { return SubjectExpr; }
   void setSubjectExpr(Expr *e) { SubjectExpr = e; }
 
-  ArrayRef<ASTNode> getRawCases() const {
-    return {getTrailingObjects<ASTNode>(), static_cast<size_t>(Bits.SwitchStmt.CaseCount)};
-  }
-
-private:
-  struct AsCaseStmtWithSkippingNonCaseStmts {
-    AsCaseStmtWithSkippingNonCaseStmts() {}
-    std::optional<CaseStmt *> operator()(const ASTNode &N) const {
-      if (auto *CS = llvm::dyn_cast_or_null<CaseStmt>(N.dyn_cast<Stmt*>()))
-        return CS;
-      return std::nullopt;
-    }
-  };
-
-public:
-  using AsCaseStmtRange = OptionalTransformRange<ArrayRef<ASTNode>,
-                            AsCaseStmtWithSkippingNonCaseStmts>;
-  
   /// Get the list of case clauses.
-  AsCaseStmtRange getCases() const {
-    return AsCaseStmtRange(getRawCases(), AsCaseStmtWithSkippingNonCaseStmts());
+  ArrayRef<CaseStmt *> getCases() const {
+    return {getTrailingObjects<CaseStmt *>(),
+            static_cast<size_t>(Bits.SwitchStmt.CaseCount)};
   }
 
   /// Retrieve the complete set of branches for this switch statement.
diff --git a/include/swift/Parse/Parser.h b/include/swift/Parse/Parser.h
@@ -1969,7 +1969,8 @@ class Parser {
   ParserResult<CaseStmt> parseStmtCatch();
   ParserResult<Stmt> parseStmtForEach(LabeledStmtInfo LabelInfo);
   ParserResult<Stmt> parseStmtSwitch(LabeledStmtInfo LabelInfo);
-  ParserStatus parseStmtCases(SmallVectorImpl<ASTNode> &cases, bool IsActive);
+  ParserStatus parseStmtCases(SmallVectorImpl<CaseStmt *> &cases,
+                              bool IsActive);
   ParserResult<CaseStmt> parseStmtCase(bool IsActive);
   ParserResult<Stmt> parseStmtPoundAssert();
 
diff --git a/lib/AST/ASTDumper.cpp b/lib/AST/ASTDumper.cpp
@@ -3123,12 +3123,9 @@ class PrintStmt : public StmtVisitor<PrintStmt, void, Label>,
   void visitSwitchStmt(SwitchStmt *S, Label label) {
     printCommon(S, "switch_stmt", label);
     printRec(S->getSubjectExpr(), Label::optional("subject_expr"));
-    printList(S->getRawCases(), [&](ASTNode N, Label label) {
-      if (N.is<Stmt*>())
-        printRec(N.get<Stmt*>(), label);
-      else
-        printRec(N.get<Decl*>(), label);
-    }, Label::optional("cases"));
+    printList(
+        S->getCases(), [&](CaseStmt *CS, Label label) { printRec(CS, label); },
+        Label::optional("cases"));
     printFoot();
   }
   void visitCaseStmt(CaseStmt *S, Label label) {
diff --git a/lib/AST/ASTPrinter.cpp b/lib/AST/ASTPrinter.cpp
@@ -5657,9 +5657,8 @@ void PrintAST::visitSwitchStmt(SwitchStmt *stmt) {
   visit(stmt->getSubjectExpr());
   Printer << " {";
   Printer.printNewline();
-  for (auto N : stmt->getRawCases()) {
-    if (N.is<Stmt*>())
-      visit(cast<CaseStmt>(N.get<Stmt*>()));
+  for (auto *CS : stmt->getCases()) {
+    visit(CS);
     Printer.printNewline();
   }
   indent();
diff --git a/lib/AST/ASTWalker.cpp b/lib/AST/ASTWalker.cpp
@@ -2063,15 +2063,12 @@ Stmt *Traversal::visitSwitchStmt(SwitchStmt *S) {
   else
     return nullptr;
 
-  for (auto N : S->getRawCases()) {
-    if (Stmt *aCase = N.dyn_cast<Stmt*>()) {
-      assert(isa<CaseStmt>(aCase));
-      if (Stmt *aStmt = doIt(aCase)) {
-        assert(aCase == aStmt && "switch case remap not supported");
-        (void)aStmt;
-      } else
-        return nullptr;
-    }
+  for (auto *aCase : S->getCases()) {
+    if (Stmt *aStmt = doIt(aCase)) {
+      assert(aCase == aStmt && "switch case remap not supported");
+      (void)aStmt;
+    } else
+      return nullptr;
   }
 
   return S;
diff --git a/lib/AST/Bridging/StmtBridging.cpp b/lib/AST/Bridging/StmtBridging.cpp
@@ -251,9 +251,9 @@ BridgedSwitchStmt BridgedSwitchStmt_createParsed(
     BridgedSourceLoc cLBraceLoc, BridgedArrayRef cCases,
     BridgedSourceLoc cRBraceLoc) {
   auto &context = cContext.unbridged();
-  auto cases =
-      context.AllocateTransform<ASTNode>(cCases.unbridged<BridgedASTNode>(),
-                                         [](auto &e) { return e.unbridged(); });
+  SmallVector<CaseStmt *, 16> cases;
+  for (auto cCase : cCases.unbridged<BridgedCaseStmt>())
+    cases.push_back(cCase.unbridged());
   return SwitchStmt::create(cLabelInfo.unbridged(), cSwitchLoc.unbridged(),
                             cSubjectExpr.unbridged(), cLBraceLoc.unbridged(),
                             cases, cRBraceLoc.unbridged(),
diff --git a/lib/AST/Stmt.cpp b/lib/AST/Stmt.cpp
@@ -940,26 +940,18 @@ CaseStmt *CaseStmt::findNextCaseStmt() const {
 }
 
 SwitchStmt *SwitchStmt::create(LabeledStmtInfo LabelInfo, SourceLoc SwitchLoc,
-                               Expr *SubjectExpr,
-                               SourceLoc LBraceLoc,
-                               ArrayRef<ASTNode> Cases,
-                               SourceLoc RBraceLoc,
-                               SourceLoc EndLoc,
-                               ASTContext &C) {
-#ifndef NDEBUG
-  for (auto N : Cases)
-    assert(N.is<Stmt*>() && isa<CaseStmt>(N.get<Stmt*>()));
-#endif
-
-  void *p = C.Allocate(totalSizeToAlloc<ASTNode>(Cases.size()),
+                               Expr *SubjectExpr, SourceLoc LBraceLoc,
+                               ArrayRef<CaseStmt *> Cases, SourceLoc RBraceLoc,
+                               SourceLoc EndLoc, ASTContext &C) {
+  void *p = C.Allocate(totalSizeToAlloc<CaseStmt *>(Cases.size()),
                        alignof(SwitchStmt));
   SwitchStmt *theSwitch = ::new (p) SwitchStmt(LabelInfo, SwitchLoc,
                                                SubjectExpr, LBraceLoc,
                                                Cases.size(), RBraceLoc,
                                                EndLoc);
 
   std::uninitialized_copy(Cases.begin(), Cases.end(),
-                          theSwitch->getTrailingObjects<ASTNode>());
+                          theSwitch->getTrailingObjects<CaseStmt *>());
   for (auto *caseStmt : theSwitch->getCases())
     caseStmt->setParentStmt(theSwitch);
 
diff --git a/lib/ASTGen/Sources/ASTGen/Stmts.swift b/lib/ASTGen/Sources/ASTGen/Stmts.swift
@@ -502,7 +502,7 @@ extension ASTGenVisitor {
   }
 
   func generate(switchCaseList node: SwitchCaseListSyntax) -> BridgedArrayRef {
-    var allBridgedCases: [BridgedASTNode] = []
+    var allBridgedCases: [BridgedCaseStmt] = []
     visitIfConfigElements(node, of: SwitchCaseSyntax.self) { element in
       switch element {
       case .ifConfigDecl(let ifConfigDecl):
@@ -511,11 +511,11 @@ extension ASTGenVisitor {
         return .underlying(switchCase)
       }
     } body: { caseNode in
-      allBridgedCases.append(
-        .stmt(self.generate(switchCase: caseNode).asStmt)
-      )
+      allBridgedCases.append(self.generate(switchCase: caseNode))
     }
 
+    // TODO: Diagnose 'case' after 'default'.
+
     return allBridgedCases.lazy.bridgedArray(in: self)
   }
 
diff --git a/lib/Parse/ParseStmt.cpp b/lib/Parse/ParseStmt.cpp
@@ -2529,7 +2529,7 @@ ParserResult<Stmt> Parser::parseStmtSwitch(LabeledStmtInfo LabelInfo) {
 
   SourceLoc lBraceLoc;
   SourceLoc rBraceLoc;
-  SmallVector<ASTNode, 8> cases;
+  SmallVector<CaseStmt *, 8> cases;
 
   if (Status.isErrorOrHasCompletion()) {
     return makeParserResult(
@@ -2551,9 +2551,7 @@ ParserResult<Stmt> Parser::parseStmtSwitch(LabeledStmtInfo LabelInfo) {
   // We cannot have additional cases after a default clause. Complain on
   // the first offender.
   bool hasDefault = false;
-  for (auto Element : cases) {
-    if (!Element.is<Stmt*>()) continue;
-    auto *CS = cast<CaseStmt>(Element.get<Stmt*>());
+  for (auto *CS : cases) {
     if (hasDefault) {
       diagnose(CS->getLoc(), diag::case_after_default);
       break;
@@ -2572,8 +2570,8 @@ ParserResult<Stmt> Parser::parseStmtSwitch(LabeledStmtInfo LabelInfo) {
                                  /*EndLoc=*/rBraceLoc, Context));
 }
 
-ParserStatus
-Parser::parseStmtCases(SmallVectorImpl<ASTNode> &cases, bool IsActive) {
+ParserStatus Parser::parseStmtCases(SmallVectorImpl<CaseStmt *> &cases,
+                                    bool IsActive) {
   ParserStatus Status;
   while (Tok.isNot(tok::r_brace, tok::eof,
                    tok::pound_endif, tok::pound_elseif, tok::pound_else)) {
@@ -2586,15 +2584,14 @@ Parser::parseStmtCases(SmallVectorImpl<ASTNode> &cases, bool IsActive) {
       // '#if' in 'case' position can enclose one or more 'case' or 'default'
       // clauses.
       auto IfConfigResult =
-          parseIfConfig(IfConfigContext::SwitchStmt,
-                        [&](bool IsActive) {
-                          SmallVector<ASTNode, 16> elements;
-                          parseStmtCases(elements, IsActive);
-
-                          if (IsActive) {
-                            cases.append(elements);
-                          }
-                        });
+          parseIfConfig(IfConfigContext::SwitchStmt, [&](bool IsActive) {
+            SmallVector<CaseStmt *, 16> elements;
+            parseStmtCases(elements, IsActive);
+
+            if (IsActive) {
+              cases.append(elements);
+            }
+          });
       Status |= IfConfigResult;
     } else if (Tok.is(tok::pound_warning) || Tok.is(tok::pound_error)) {
       Status |= parseDeclPoundDiagnostic();
diff --git a/lib/SILGen/SILGenPattern.cpp b/lib/SILGen/SILGenPattern.cpp
@@ -3455,7 +3455,7 @@ void SILGenFunction::emitSwitchStmt(SwitchStmt *S) {
 
   // Add a row for each label of each case.
   SmallVector<ClauseRow, 8> clauseRows;
-  clauseRows.reserve(S->getRawCases().size());
+  clauseRows.reserve(S->getCases().size());
   bool hasFallthrough = false;
   for (auto caseBlock : S->getCases()) {
     // If the previous block falls through into this block or we have multiple
diff --git a/lib/Sema/BuilderTransform.cpp b/lib/Sema/BuilderTransform.cpp
@@ -585,7 +585,7 @@ class ResultBuilderTransform
     // type-checked first.
     SmallVector<ASTNode, 4> doBody;
 
-    SmallVector<ASTNode, 4> cases;
+    SmallVector<CaseStmt *, 4> cases;
     SmallVector<Expr *, 4> caseVarRefs;
 
     for (auto *caseStmt : switchStmt->getCases()) {
diff --git a/lib/Sema/CSSyntacticElement.cpp b/lib/Sema/CSSyntacticElement.cpp
@@ -1059,8 +1059,8 @@ class SyntacticElementConstraintGenerator
         cs.setTargetFor(switchStmt, target);
       }
 
-      for (auto rawCase : switchStmt->getRawCases())
-        elements.push_back(makeElement(rawCase, locator));
+      for (auto &CS : switchStmt->getCases())
+        elements.push_back(makeElement(CS, locator));
     }
 
     createConjunction(elements, locator);
@@ -1963,18 +1963,12 @@ class SyntacticElementSolutionApplication
 
     // Visit the raw cases.
     bool limitExhaustivityChecks = false;
-    for (auto rawCase : switchStmt->getRawCases()) {
-      if (auto decl = rawCase.dyn_cast<Decl *>()) {
-        visitDecl(decl);
-        continue;
-      }
-
-      auto caseStmt = cast<CaseStmt>(rawCase.get<Stmt *>());
+    for (auto *CS : switchStmt->getCases()) {
       // Body of the `case` statement can contain a `fallthrough`
       // statement that requires both source and destination
       // `case` preambles to be type-checked, so bodies of `case`
       // statements should be visited after preambles.
-      visitCaseStmtPreamble(caseStmt);
+      visitCaseStmtPreamble(CS);
     }
 
     for (auto *caseStmt : switchStmt->getCases()) {
diff --git a/lib/Sema/DerivedConformanceCodable.cpp b/lib/Sema/DerivedConformanceCodable.cpp
@@ -931,7 +931,7 @@ createEnumSwitch(ASTContext &C, DeclContext *DC, Expr *expr, EnumDecl *enumDecl,
                  std::function<std::tuple<EnumElementDecl *, BraceStmt *>(
                      EnumElementDecl *, EnumElementDecl *, ArrayRef<VarDecl *>)>
                      createCase) {
-  SmallVector<ASTNode, 4> cases;
+  SmallVector<CaseStmt *, 4> cases;
   for (auto elt : enumDecl->getAllElements()) {
     // .<elt>(let a0, let a1, ...)
     SmallVector<VarDecl *, 3> payloadVars;
diff --git a/lib/Sema/DerivedConformanceCodingKey.cpp b/lib/Sema/DerivedConformanceCodingKey.cpp
@@ -209,7 +209,7 @@ deriveBodyCodingKey_enum_stringValue(AbstractFunctionDecl *strValDecl, void *) {
     body = BraceStmt::create(C, SourceLoc(), ASTNode(returnStmt),
                              SourceLoc());
   } else {
-    SmallVector<ASTNode, 4> cases;
+    SmallVector<CaseStmt *, 4> cases;
     for (auto *elt : elements) {
       auto *pat = EnumElementPattern::createImplicit(enumType, elt,
                                                      /*subPattern*/ nullptr,
@@ -270,7 +270,7 @@ deriveBodyCodingKey_init_stringValue(AbstractFunctionDecl *initDecl, void *) {
   }
 
   auto *selfRef = DerivedConformance::createSelfDeclRef(initDecl);
-  SmallVector<ASTNode, 4> cases;
+  SmallVector<CaseStmt *, 4> cases;
   for (auto *elt : elements) {
     // Skip the cases that would return unavailable elements since those can't
     // be instantiated at runtime.
diff --git a/lib/Sema/DerivedConformanceComparable.cpp b/lib/Sema/DerivedConformanceComparable.cpp
@@ -103,7 +103,7 @@ deriveBodyComparable_enum_hasAssociatedValues_lt(AbstractFunctionDecl *ltDecl, v
   auto enumDecl = cast<EnumDecl>(aParam->getInterfaceType()->getAnyNominal());
 
   SmallVector<ASTNode, 8> statements;
-  SmallVector<ASTNode, 4> cases;
+  SmallVector<CaseStmt *, 4> cases;
   unsigned elementCount = 0; // need this as `getAllElements` returns a generator
 
   // For each enum element, generate a case statement matching a pair containing
diff --git a/lib/Sema/DerivedConformanceEquatableHashable.cpp b/lib/Sema/DerivedConformanceEquatableHashable.cpp
@@ -69,7 +69,7 @@ deriveBodyEquatable_enum_uninhabited_eq(AbstractFunctionDecl *eqDecl, void *) {
   assert(!cast<EnumDecl>(aParam->getInterfaceType()->getAnyNominal())->hasCases());
 
   SmallVector<ASTNode, 1> statements;
-  SmallVector<ASTNode, 0> cases;
+  SmallVector<CaseStmt *, 0> cases;
 
   // switch (a, b) { }
   auto aRef = new (C) DeclRefExpr(aParam, DeclNameLoc(), /*implicit*/ true,
@@ -163,7 +163,7 @@ deriveBodyEquatable_enum_hasAssociatedValues_eq(AbstractFunctionDecl *eqDecl,
   auto enumDecl = cast<EnumDecl>(aParam->getInterfaceType()->getAnyNominal());
 
   SmallVector<ASTNode, 6> statements;
-  SmallVector<ASTNode, 4> cases;
+  SmallVector<CaseStmt *, 4> cases;
   unsigned elementCount = 0;
 
   // For each enum element, generate a case statement matching a pair containing
@@ -687,7 +687,7 @@ deriveBodyHashable_enum_hasAssociatedValues_hashInto(
   auto hasherParam = hashIntoDecl->getParameters()->get(0);
 
   unsigned index = 0;
-  SmallVector<ASTNode, 4> cases;
+  SmallVector<CaseStmt *, 4> cases;
 
   // For each enum element, generate a case statement that binds the associated
   // values so that they can be fed to the hasher.
diff --git a/lib/Sema/DerivedConformanceRawRepresentable.cpp b/lib/Sema/DerivedConformanceRawRepresentable.cpp
@@ -114,7 +114,7 @@ deriveBodyRawRepresentable_raw(AbstractFunctionDecl *toRawDecl, void *) {
 
   Type enumType = parentDC->getDeclaredTypeInContext();
 
-  SmallVector<ASTNode, 4> cases;
+  SmallVector<CaseStmt *, 4> cases;
   for (auto elt : enumDecl->getAllElements()) {
     auto *pat = EnumElementPattern::createImplicit(
         enumType, elt, /*subPattern*/ nullptr, /*DC*/ toRawDecl);
@@ -311,8 +311,8 @@ deriveBodyRawRepresentable_init(AbstractFunctionDecl *initDecl, void *) {
   Type enumType = parentDC->getDeclaredTypeInContext();
 
   auto selfDecl = cast<ConstructorDecl>(initDecl)->getImplicitSelfDecl();
-  
-  SmallVector<ASTNode, 4> cases;
+
+  SmallVector<CaseStmt *, 4> cases;
   unsigned Idx = 0;
   for (auto elt : enumDecl->getAllElements()) {
     // First, check case availability. If the case will definitely be
diff --git a/lib/Sema/DerivedConformances.cpp b/lib/Sema/DerivedConformances.cpp
@@ -771,7 +771,7 @@ DeclRefExpr *DerivedConformance::convertEnumToIndex(SmallVectorImpl<ASTNode> &st
       C, StaticSpellingKind::None, indexPat, /*InitExpr*/ nullptr, funcDecl);
 
   unsigned index = 0;
-  SmallVector<ASTNode, 4> cases;
+  SmallVector<CaseStmt *, 4> cases;
   for (auto elt : enumDecl->getAllElements()) {
     if (auto *unavailableElementCase =
             DerivedConformance::unavailableEnumElementCaseStmt(enumType, elt,
diff --git a/lib/Sema/TypeCheckStmt.cpp b/lib/Sema/TypeCheckStmt.cpp

Original file line number	Diff line number	Diff line change
`@@ -502,7 +502,7 @@ extension ASTGenVisitor {`
`502`	`502`	`}`
`503`	`503`
`504`	`504`	`func generate(switchCaseList node: SwitchCaseListSyntax) -> BridgedArrayRef {`
`505`		`- var allBridgedCases: [BridgedASTNode] = []`
	`505`	`+ var allBridgedCases: [BridgedCaseStmt] = []`
`506`	`506`	`visitIfConfigElements(node, of: SwitchCaseSyntax.self) { element in`
`507`	`507`	`switch element {`
`508`	`508`	`case .ifConfigDecl(let ifConfigDecl):`
`@@ -511,11 +511,11 @@ extension ASTGenVisitor {`
`511`	`511`	`return .underlying(switchCase)`
`512`	`512`	`}`
`513`	`513`	`} body: { caseNode in`
`514`		`- allBridgedCases.append(`
`515`		`- .stmt(self.generate(switchCase: caseNode).asStmt)`
`516`		`- )`
	`514`	`+ allBridgedCases.append(self.generate(switchCase: caseNode))`
`517`	`515`	`}`
`518`	`516`
	`517`	`+ // TODO: Diagnose 'case' after 'default'.`
	`518`	`+`
`519`	`519`	`return allBridgedCases.lazy.bridgedArray(in: self)`
`520`	`520`	`}`
`521`	`521`