AST: The body of a CaseStmt is always a BraceStmt

Author: slavapestov

include/swift/AST/Stmt.h

@@ -945,13 +945,13 @@ class CaseStmt final
   SourceLoc ItemTerminatorLoc;
   CaseParentKind ParentKind;
 
-  llvm::PointerIntPair<Stmt *, 1, bool> BodyAndHasFallthrough;
+  llvm::PointerIntPair<BraceStmt *, 1, bool> BodyAndHasFallthrough;
 
   Optional<MutableArrayRef<VarDecl *>> CaseBodyVariables;
 
   CaseStmt(CaseParentKind ParentKind, SourceLoc ItemIntroducerLoc,
            ArrayRef<CaseLabelItem> CaseLabelItems, SourceLoc UnknownAttrLoc,
-           SourceLoc ItemTerminatorLoc, Stmt *Body,
+           SourceLoc ItemTerminatorLoc, BraceStmt *Body,
            Optional<MutableArrayRef<VarDecl *>> CaseBodyVariables,
            Optional<bool> Implicit,
            NullablePtr<FallthroughStmt> fallthroughStmt);
@@ -960,7 +960,7 @@ class CaseStmt final
   static CaseStmt *
   create(ASTContext &C, CaseParentKind ParentKind, SourceLoc ItemIntroducerLoc,
          ArrayRef<CaseLabelItem> CaseLabelItems, SourceLoc UnknownAttrLoc,
-         SourceLoc ItemTerminatorLoc, Stmt *Body,
+         SourceLoc ItemTerminatorLoc, BraceStmt *Body,
          Optional<MutableArrayRef<VarDecl *>> CaseBodyVariables,
          Optional<bool> Implicit = None,
          NullablePtr<FallthroughStmt> fallthroughStmt = nullptr);
@@ -997,8 +997,8 @@ class CaseStmt final
 
   bool hasFallthroughDest() const { return BodyAndHasFallthrough.getInt(); }
 
-  Stmt *getBody() const { return BodyAndHasFallthrough.getPointer(); }
-  void setBody(Stmt *body) { BodyAndHasFallthrough.setPointer(body); }
+  BraceStmt *getBody() const { return BodyAndHasFallthrough.getPointer(); }
+  void setBody(BraceStmt *body) { BodyAndHasFallthrough.setPointer(body); }
 
   /// True if the case block declares any patterns with local variable bindings.
   bool hasBoundDecls() const { return CaseBodyVariables.hasValue(); }

lib/AST/ASTWalker.cpp

@@ -1631,7 +1631,7 @@ Stmt *Traversal::visitCaseStmt(CaseStmt *S) {
     }
   }
 
-  if (Stmt *newBody = doIt(S->getBody()))
+  if (BraceStmt *newBody = cast_or_null<BraceStmt>(doIt(S->getBody())))
     S->setBody(newBody);
   else
     return nullptr;

lib/AST/Stmt.cpp

@@ -407,7 +407,7 @@ SourceLoc CaseLabelItem::getEndLoc() const {
 CaseStmt::CaseStmt(CaseParentKind parentKind, SourceLoc itemIntroducerLoc,
                    ArrayRef<CaseLabelItem> caseLabelItems,
                    SourceLoc unknownAttrLoc, SourceLoc itemTerminatorLoc,
-                   Stmt *body,
+                   BraceStmt *body,
                    Optional<MutableArrayRef<VarDecl *>> caseBodyVariables,
                    Optional<bool> implicit,
                    NullablePtr<FallthroughStmt> fallthroughStmt)
@@ -445,7 +445,7 @@ CaseStmt *CaseStmt::create(ASTContext &ctx, CaseParentKind ParentKind,
                            SourceLoc caseLoc,
                            ArrayRef<CaseLabelItem> caseLabelItems,
                            SourceLoc unknownAttrLoc, SourceLoc colonLoc,
-                           Stmt *body,
+                           BraceStmt *body,
                            Optional<MutableArrayRef<VarDecl *>> caseVarDecls,
                            Optional<bool> implicit,
                            NullablePtr<FallthroughStmt> fallthroughStmt) {

lib/Sema/TypeCheckStmt.cpp

@@ -1150,7 +1150,7 @@ class StmtChecker : public StmtVisitor<StmtChecker, Stmt*> {
             getASTContext(), caseBlock, limitExhaustivityChecks);
       }
 
-      Stmt *body = caseBlock->getBody();
+      BraceStmt *body = caseBlock->getBody();
       limitExhaustivityChecks |= typeCheckStmt(body);
       caseBlock->setBody(body);
     }