[DNM] Fix SILGenPattern fallthrough issues.

include/swift/AST/Stmt.h

@@ -17,12 +17,13 @@
 #ifndef SWIFT_AST_STMT_H
 #define SWIFT_AST_STMT_H
 
+#include "swift/AST/ASTNode.h"
 #include "swift/AST/Availability.h"
 #include "swift/AST/AvailabilitySpec.h"
-#include "swift/AST/ASTNode.h"
 #include "swift/AST/IfConfigClause.h"
 #include "swift/AST/TypeAlignments.h"
 #include "swift/Basic/NullablePtr.h"
+#include "llvm/ADT/TinyPtrVector.h"
 #include "llvm/Support/TrailingObjects.h"
 
 namespace swift {
@@ -943,6 +944,8 @@ class CaseStmt final : public Stmt,
 
   llvm::PointerIntPair<Stmt *, 1, bool> BodyAndHasBoundDecls;
 
+  Optional<MutableArrayRef<VarDecl>> CaseBodyVariables;
+
   CaseStmt(SourceLoc CaseLoc, ArrayRef<CaseLabelItem> CaseLabelItems,
            bool HasBoundDecls, SourceLoc UnknownAttrLoc, SourceLoc ColonLoc,
            Stmt *Body, Optional<bool> Implicit);
@@ -990,6 +993,19 @@ class CaseStmt final : public Stmt,
     return UnknownAttrLoc.isValid();
   }
 
+  bool isCaseBodyVariablesInitialized() const {
+    return CaseBodyVariables.hasValue();
+  }
+
+  ArrayRef<VarDecl> getCaseBodyVariables() const { return *CaseBodyVariables; }
+
+  MutableArrayRef<VarDecl> getCaseBodyVariables() { return *CaseBodyVariables; }
+
+  void setCaseBodyVariables(MutableArrayRef<VarDecl> Variables) {
+    assert(!CaseBodyVariables && "Setting a case stmts case body vars twice?!");
+    CaseBodyVariables = Variables;
+  }
+
   static bool classof(const Stmt *S) { return S->getKind() == StmtKind::Case; }
 };
 

lib/AST/ASTDumper.cpp

@@ -1619,6 +1619,24 @@ class PrintStmt : public StmtVisitor<PrintStmt> {
     printCommon(S, "case_stmt");
     if (S->hasUnknownAttr())
       OS << " @unknown";
+
+    if (S->getCaseBodyVariables().size()) {
+      OS << '\n';
+      OS.indent(Indent + 2);
+      PrintWithColorRAII(OS, ParenthesisColor) << '(';
+      PrintWithColorRAII(OS, StmtColor) << "case_body_variables";
+      OS << '\n';
+      for (auto &vd : S->getCaseBodyVariables()) {
+        OS.indent(2);
+        // TODO: Printing a var decl does an Indent ... dump(vd) ... '\n'. We
+        // should see if we can factor this dumping so that the caller of
+        // printRec(VarDecl) has more control over the printing.
+        printRec(&vd);
+      }
+      OS.indent(Indent + 2);
+      PrintWithColorRAII(OS, ParenthesisColor) << ')';
+    }
+
     for (const auto &LabelItem : S->getCaseLabelItems()) {
       OS << '\n';
       OS.indent(Indent + 2);

lib/AST/NameLookup.cpp

@@ -2931,8 +2931,14 @@ void FindLocalVal::visitCaseStmt(CaseStmt *S) {
       }
     }
   }
-  if (!inPatterns && !items.empty())
-    checkPattern(items[0].getPattern(), DeclVisibilityKind::LocalVariable);
+
+  // Then check the var decls for the case body.
+  if (!inPatterns && !items.empty()) {
+    for (auto &vd : S->getCaseBodyVariables()) {
+      checkValueDecl(&vd, DeclVisibilityKind::LocalVariable);
+    }
+  }
+
   visit(S->getBody());
 }