Rearrange condition handling so that semantic checks on a condition variable

are performed before the other substatements of the construct are parsed,
rather than deferring them until the end. This allows better error recovery
from semantic errors in the condition, improves diagnostic order, and is a
prerequisite for C++17 constexpr if.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@273548 91177308-0d34-0410-b5e6-96231b3b80d8

16 files changed, 294 insertions, 374 deletions

diff --git a/include/clang/Parse/Parser.h b/include/clang/Parse/Parser.h
index 9cbad6b634..3ddbcf5245 100644
--- a/include/clang/Parse/Parser.h
+++ b/include/clang/Parse/Parser.h
@@ -1588,8 +1588,8 @@ private:
 
   //===--------------------------------------------------------------------===//
   // C++ if/switch/while condition expression.
-  bool ParseCXXCondition(ExprResult &ExprResult, Decl *&DeclResult,
-                         SourceLocation Loc, bool ConvertToBoolean);
+  Sema::ConditionResult ParseCXXCondition(SourceLocation Loc,
+                                          Sema::ConditionKind CK);
 
   //===--------------------------------------------------------------------===//
   // C++ Coroutines
@@ -1680,10 +1680,9 @@ private:
                                     unsigned ScopeFlags);
   void ParseCompoundStatementLeadingPragmas();
   StmtResult ParseCompoundStatementBody(bool isStmtExpr = false);
-  bool ParseParenExprOrCondition(ExprResult &ExprResult,
-                                 Decl *&DeclResult,
+  bool ParseParenExprOrCondition(Sema::ConditionResult &CondResult,
                                  SourceLocation Loc,
-                                 bool ConvertToBoolean);
+                                 Sema::ConditionKind CK);
   StmtResult ParseIfStatement(SourceLocation *TrailingElseLoc);
   StmtResult ParseSwitchStatement(SourceLocation *TrailingElseLoc);
   StmtResult ParseWhileStatement(SourceLocation *TrailingElseLoc);
diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index 977ffb4dd2..7f2a942962 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -3298,6 +3298,7 @@ public:
 public:
   class FullExprArg {
   public:
+    FullExprArg() : E(nullptr) { }
     FullExprArg(Sema &actions) : E(nullptr) { }
 
     ExprResult release() {
@@ -3391,27 +3392,23 @@ public:
                                  ArrayRef<const Attr*> Attrs,
                                  Stmt *SubStmt);
 
-  StmtResult ActOnIfStmt(SourceLocation IfLoc,
-                         FullExprArg CondVal, Decl *CondVar,
-                         Stmt *ThenVal,
-                         SourceLocation ElseLoc, Stmt *ElseVal);
+  class ConditionResult;
+  StmtResult ActOnIfStmt(SourceLocation IfLoc, ConditionResult Cond,
+                         Stmt *ThenVal, SourceLocation ElseLoc, Stmt *ElseVal);
   StmtResult ActOnStartOfSwitchStmt(SourceLocation SwitchLoc,
-                                            Expr *Cond,
-                                            Decl *CondVar);
+                                    ConditionResult Cond);
   StmtResult ActOnFinishSwitchStmt(SourceLocation SwitchLoc,
                                            Stmt *Switch, Stmt *Body);
-  StmtResult ActOnWhileStmt(SourceLocation WhileLoc,
-                            FullExprArg Cond,
-                            Decl *CondVar, Stmt *Body);
+  StmtResult ActOnWhileStmt(SourceLocation WhileLoc, ConditionResult Cond,
+                            Stmt *Body);
   StmtResult ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
-                                 SourceLocation WhileLoc,
-                                 SourceLocation CondLParen, Expr *Cond,
-                                 SourceLocation CondRParen);
+                         SourceLocation WhileLoc, SourceLocation CondLParen,
+                         Expr *Cond, SourceLocation CondRParen);
 
   StmtResult ActOnForStmt(SourceLocation ForLoc,
                           SourceLocation LParenLoc,
-                          Stmt *First, FullExprArg Second,
-                          Decl *SecondVar,
+                          Stmt *First,
+                          ConditionResult Second,
                           FullExprArg Third,
                           SourceLocation RParenLoc,
                           Stmt *Body);
@@ -4801,11 +4798,6 @@ public:
                             bool WarnOnNonAbstractTypes,
                             SourceLocation DtorLoc);
 
-  DeclResult ActOnCXXConditionDeclaration(Scope *S, Declarator &D);
-  ExprResult CheckConditionVariable(VarDecl *ConditionVar,
-                                    SourceLocation StmtLoc,
-                                    bool ConvertToBoolean);
-
   ExprResult ActOnNoexceptExpr(SourceLocation KeyLoc, SourceLocation LParen,
                                Expr *Operand, SourceLocation RParen);
   ExprResult BuildCXXNoexceptExpr(SourceLocation KeyLoc, Expr *Operand,
@@ -8923,6 +8915,46 @@ public:
   /// type, and if so, emit a note describing what happened.
   void EmitRelatedResultTypeNoteForReturn(QualType destType);
 
+  class ConditionResult {
+    Decl *ConditionVar;
+    FullExprArg Condition;
+    bool Invalid;
+
+    friend class Sema;
+    ConditionResult(Decl *ConditionVar, FullExprArg Condition)
+        : ConditionVar(ConditionVar), Condition(Condition), Invalid(false) {}
+    explicit ConditionResult(bool Invalid)
+        : ConditionVar(nullptr), Condition(nullptr), Invalid(Invalid) {}
+
+  public:
+    ConditionResult() : ConditionResult(false) {}
+    bool isInvalid() const { return Invalid; }
+    std::pair<VarDecl *, Expr *> get() const {
+      return std::make_pair(cast_or_null<VarDecl>(ConditionVar),
+                            Condition.get());
+    }
+  };
+  static ConditionResult ConditionError() { return ConditionResult(true); }
+
+  enum class ConditionKind {
+    Boolean, ///< A boolean condition, from 'if', 'while', 'for', or 'do'.
+    Switch   ///< An integral condition for a 'switch' statement.
+  };
+
+  ConditionResult ActOnCondition(Scope *S, SourceLocation Loc,
+                                 Expr *SubExpr, ConditionKind CK);
+
+  ConditionResult ActOnConditionVariable(Decl *ConditionVar,
+                                         SourceLocation StmtLoc,
+                                         ConditionKind CK);
+
+  DeclResult ActOnCXXConditionDeclaration(Scope *S, Declarator &D);
+
+  ExprResult CheckConditionVariable(VarDecl *ConditionVar,
+                                    SourceLocation StmtLoc,
+                                    ConditionKind CK);
+  ExprResult CheckSwitchCondition(SourceLocation SwitchLoc, Expr *Cond);
+
   /// CheckBooleanCondition - Diagnose problems involving the use of
   /// the given expression as a boolean condition (e.g. in an if
   /// statement).  Also performs the standard function and array
@@ -8931,10 +8963,7 @@ public:
   /// \param Loc - A location associated with the condition, e.g. the
   /// 'if' keyword.
   /// \return true iff there were any errors
-  ExprResult CheckBooleanCondition(Expr *E, SourceLocation Loc);
-
-  ExprResult ActOnBooleanCondition(Scope *S, SourceLocation Loc,
-                                   Expr *SubExpr);
+  ExprResult CheckBooleanCondition(SourceLocation Loc, Expr *E);
 
   /// DiagnoseAssignmentAsCondition - Given that an expression is
   /// being used as a boolean condition, warn if it's an assignment.
diff --git a/lib/Parse/ParseDeclCXX.cpp b/lib/Parse/ParseDeclCXX.cpp
index d55b2d9442..5718e1e50e 100644
--- a/lib/Parse/ParseDeclCXX.cpp
+++ b/lib/Parse/ParseDeclCXX.cpp
@@ -3420,10 +3420,11 @@ Parser::tryParseExceptionSpecification(bool Delayed,
     NoexceptExpr = ParseConstantExpression();
     T.consumeClose();
     // The argument must be contextually convertible to bool. We use
-    // ActOnBooleanCondition for this purpose.
+    // CheckBooleanCondition for this purpose.
+    // FIXME: Add a proper Sema entry point for this.
     if (!NoexceptExpr.isInvalid()) {
-      NoexceptExpr = Actions.ActOnBooleanCondition(getCurScope(), KeywordLoc,
-                                                   NoexceptExpr.get());
+      NoexceptExpr =
+          Actions.CheckBooleanCondition(KeywordLoc, NoexceptExpr.get());
       NoexceptRange = SourceRange(KeywordLoc, T.getCloseLocation());
     } else {
       NoexceptType = EST_None;
diff --git a/lib/Parse/ParseExprCXX.cpp b/lib/Parse/ParseExprCXX.cpp
index b0740970d8..00f20e5e7b 100644
--- a/lib/Parse/ParseExprCXX.cpp
+++ b/lib/Parse/ParseExprCXX.cpp
@@ -1726,27 +1726,19 @@ Parser::ParseCXXTypeConstructExpression(const DeclSpec &DS) {
 /// [GNU]   type-specifier-seq declarator simple-asm-expr[opt] attributes[opt]
 ///             '=' assignment-expression
 ///
-/// \param ExprOut if the condition was parsed as an expression, the parsed
-/// expression.
-///
-/// \param DeclOut if the condition was parsed as a declaration, the parsed
-/// declaration.
-///
 /// \param Loc The location of the start of the statement that requires this
 /// condition, e.g., the "for" in a for loop.
 ///
 /// \param ConvertToBoolean Whether the condition expression should be
 /// converted to a boolean value.
 ///
-/// \returns true if there was a parsing, false otherwise.
-bool Parser::ParseCXXCondition(ExprResult &ExprOut,
-                               Decl *&DeclOut,
-                               SourceLocation Loc,
-                               bool ConvertToBoolean) {
+/// \returns The parsed condition.
+Sema::ConditionResult Parser::ParseCXXCondition(SourceLocation Loc,
+                                                Sema::ConditionKind CK) {
   if (Tok.is(tok::code_completion)) {
     Actions.CodeCompleteOrdinaryName(getCurScope(), Sema::PCC_Condition);
     cutOffParsing();
-    return true;
+    return Sema::ConditionError();
   }
 
   ParsedAttributesWithRange attrs(AttrFactory);
@@ -1756,16 +1748,11 @@ bool Parser::ParseCXXCondition(ExprResult &ExprOut,
     ProhibitAttributes(attrs);
 
     // Parse the expression.
-    ExprOut = ParseExpression(); // expression
-    DeclOut = nullptr;
-    if (ExprOut.isInvalid())
-      return true;
+    ExprResult Expr = ParseExpression(); // expression
+    if (Expr.isInvalid())
+      return Sema::ConditionError();
 
-    // If required, convert to a boolean value.
-    if (ConvertToBoolean)
-      ExprOut
-        = Actions.ActOnBooleanCondition(getCurScope(), Loc, ExprOut.get());
-    return ExprOut.isInvalid();
+    return Actions.ActOnCondition(getCurScope(), Loc, Expr.get(), CK);
   }
 
   // type-specifier-seq
@@ -1783,7 +1770,7 @@ bool Parser::ParseCXXCondition(ExprResult &ExprOut,
     ExprResult AsmLabel(ParseSimpleAsm(&Loc));
     if (AsmLabel.isInvalid()) {
       SkipUntil(tok::semi, StopAtSemi);
-      return true;
+      return Sema::ConditionError();
     }
     DeclaratorInfo.setAsmLabel(AsmLabel.get());
     DeclaratorInfo.SetRangeEnd(Loc);
@@ -1795,8 +1782,9 @@ bool Parser::ParseCXXCondition(ExprResult &ExprOut,
   // Type-check the declaration itself.
   DeclResult Dcl = Actions.ActOnCXXConditionDeclaration(getCurScope(), 
                                                         DeclaratorInfo);
-  DeclOut = Dcl.get();
-  ExprOut = ExprError();
+  if (Dcl.isInvalid())
+    return Sema::ConditionError();
+  Decl *DeclOut = Dcl.get();
 
   // '=' assignment-expression
   // If a '==' or '+=' is found, suggest a fixit to '='.
@@ -1816,12 +1804,11 @@ bool Parser::ParseCXXCondition(ExprResult &ExprOut,
     SourceLocation LParen = ConsumeParen(), RParen = LParen;
     if (SkipUntil(tok::r_paren, StopAtSemi | StopBeforeMatch))
       RParen = ConsumeParen();
-    Diag(DeclOut ? DeclOut->getLocation() : LParen,
+    Diag(DeclOut->getLocation(),
          diag::err_expected_init_in_condition_lparen)
       << SourceRange(LParen, RParen);
   } else {
-    Diag(DeclOut ? DeclOut->getLocation() : Tok.getLocation(),
-         diag::err_expected_init_in_condition);
+    Diag(DeclOut->getLocation(), diag::err_expected_init_in_condition);
   }
 
   if (!InitExpr.isInvalid())
@@ -1834,8 +1821,7 @@ bool Parser::ParseCXXCondition(ExprResult &ExprOut,
   // (This is currently handled by Sema).
 
   Actions.FinalizeDeclaration(DeclOut);
-  
-  return false;
+  return Actions.ActOnConditionVariable(DeclOut, Loc, CK);
 }
 
 /// ParseCXXSimpleTypeSpecifier - [C++ 7.1.5.2] Simple type specifiers.
diff --git a/lib/Parse/ParseStmt.cpp b/lib/Parse/ParseStmt.cpp
index 8173d09cbb..c849554238 100644
--- a/lib/Parse/ParseStmt.cpp
+++ b/lib/Parse/ParseStmt.cpp
@@ -1052,29 +1052,28 @@ StmtResult Parser::ParseCompoundStatementBody(bool isStmtExpr) {
 /// should try to recover harder.  It returns false if the condition is
 /// successfully parsed.  Note that a successful parse can still have semantic
 /// errors in the condition.
-bool Parser::ParseParenExprOrCondition(ExprResult &ExprResult,
-                                       Decl *&DeclResult,
+bool Parser::ParseParenExprOrCondition(Sema::ConditionResult &Cond,
                                        SourceLocation Loc,
-                                       bool ConvertToBoolean) {
+                                       Sema::ConditionKind CK) {
   BalancedDelimiterTracker T(*this, tok::l_paren);
   T.consumeOpen();
 
   if (getLangOpts().CPlusPlus)
-    ParseCXXCondition(ExprResult, DeclResult, Loc, ConvertToBoolean);
+    Cond = ParseCXXCondition(Loc, CK);
   else {
-    ExprResult = ParseExpression();
-    DeclResult = nullptr;
+    ExprResult CondExpr = ParseExpression();
 
     // If required, convert to a boolean value.
-    if (!ExprResult.isInvalid() && ConvertToBoolean)
-      ExprResult
-        = Actions.ActOnBooleanCondition(getCurScope(), Loc, ExprResult.get());
+    if (CondExpr.isInvalid())
+      Cond = Sema::ConditionError();
+    else
+      Cond = Actions.ActOnCondition(getCurScope(), Loc, CondExpr.get(), CK);
   }
 
   // If the parser was confused by the condition and we don't have a ')', try to
   // recover by skipping ahead to a semi and bailing out.  If condexp is
   // semantically invalid but we have well formed code, keep going.
-  if (ExprResult.isInvalid() && !DeclResult && Tok.isNot(tok::r_paren)) {
+  if (Cond.isInvalid() && Tok.isNot(tok::r_paren)) {
     SkipUntil(tok::semi);
     // Skipping may have stopped if it found the containing ')'.  If so, we can
     // continue parsing the if statement.
@@ -1132,13 +1131,10 @@ StmtResult Parser::ParseIfStatement(SourceLocation *TrailingElseLoc) {
   ParseScope IfScope(this, Scope::DeclScope | Scope::ControlScope, C99orCXX);
 
   // Parse the condition.
-  ExprResult CondExp;
-  Decl *CondVar = nullptr;
-  if (ParseParenExprOrCondition(CondExp, CondVar, IfLoc, true))
+  Sema::ConditionResult Cond;
+  if (ParseParenExprOrCondition(Cond, IfLoc, Sema::ConditionKind::Boolean))
     return StmtError();
 
-  FullExprArg FullCondExp(Actions.MakeFullExpr(CondExp.get(), IfLoc));
-
   // C99 6.8.4p3 - In C99, the body of the if statement is a scope, even if
   // there is no compound stmt.  C90 does not have this clause.  We only do this
   // if the body isn't a compound statement to avoid push/pop in common cases.
@@ -1221,8 +1217,8 @@ StmtResult Parser::ParseIfStatement(SourceLocation *TrailingElseLoc) {
   if (ElseStmt.isInvalid())
     ElseStmt = Actions.ActOnNullStmt(ElseStmtLoc);
 
-  return Actions.ActOnIfStmt(IfLoc, FullCondExp, CondVar, ThenStmt.get(),
-                             ElseLoc, ElseStmt.get());
+  return Actions.ActOnIfStmt(IfLoc, Cond, ThenStmt.get(), ElseLoc,
+                             ElseStmt.get());
 }
 
 /// ParseSwitchStatement
@@ -1259,13 +1255,11 @@ StmtResult Parser::ParseSwitchStatement(SourceLocation *TrailingElseLoc) {
   ParseScope SwitchScope(this, ScopeFlags);
 
   // Parse the condition.
-  ExprResult Cond;
-  Decl *CondVar = nullptr;
-  if (ParseParenExprOrCondition(Cond, CondVar, SwitchLoc, false))
+  Sema::ConditionResult Cond;
+  if (ParseParenExprOrCondition(Cond, SwitchLoc, Sema::ConditionKind::Switch))
     return StmtError();
 
-  StmtResult Switch
-    = Actions.ActOnStartOfSwitchStmt(SwitchLoc, Cond.get(), CondVar);
+  StmtResult Switch = Actions.ActOnStartOfSwitchStmt(SwitchLoc, Cond);
 
   if (Switch.isInvalid()) {
     // Skip the switch body.
@@ -1347,13 +1341,10 @@ StmtResult Parser::ParseWhileStatement(SourceLocation *TrailingElseLoc) {
   ParseScope WhileScope(this, ScopeFlags);
 
   // Parse the condition.
-  ExprResult Cond;
-  Decl *CondVar = nullptr;
-  if (ParseParenExprOrCondition(Cond, CondVar, WhileLoc, true))
+  Sema::ConditionResult Cond;
+  if (ParseParenExprOrCondition(Cond, WhileLoc, Sema::ConditionKind::Boolean))
     return StmtError();
 
-  FullExprArg FullCond(Actions.MakeFullExpr(Cond.get(), WhileLoc));
-
   // C99 6.8.5p5 - In C99, the body of the while statement is a scope, even if
   // there is no compound stmt.  C90 does not have this clause.  We only do this
   // if the body isn't a compound statement to avoid push/pop in common cases.
@@ -1374,10 +1365,10 @@ StmtResult Parser::ParseWhileStatement(SourceLocation *TrailingElseLoc) {
   InnerScope.Exit();
   WhileScope.Exit();
 
-  if ((Cond.isInvalid() && !CondVar) || Body.isInvalid())
+  if (Cond.isInvalid() || Body.isInvalid())
     return StmtError();
 
-  return Actions.ActOnWhileStmt(WhileLoc, FullCond, CondVar, Body.get());
+  return Actions.ActOnWhileStmt(WhileLoc, Cond, Body.get());
 }
 
 /// ParseDoStatement
@@ -1535,12 +1526,10 @@ StmtResult Parser::ParseForStatement(SourceLocation *TrailingElseLoc) {
 
   bool ForEach = false, ForRange = false;
   StmtResult FirstPart;
-  bool SecondPartIsInvalid = false;
-  FullExprArg SecondPart(Actions);
+  Sema::ConditionResult SecondPart;
   ExprResult Collection;
   ForRangeInit ForRangeInit;
   FullExprArg ThirdPart(Actions);
-  Decl *SecondVar = nullptr;
 
   if (Tok.is(tok::code_completion)) {
     Actions.CodeCompleteOrdinaryName(getCurScope(),
@@ -1645,7 +1634,7 @@ StmtResult Parser::ParseForStatement(SourceLocation *TrailingElseLoc) {
       Diag(Tok, diag::err_for_range_expected_decl)
         << FirstPart.get()->getSourceRange();
       SkipUntil(tok::r_paren, StopBeforeMatch);
-      SecondPartIsInvalid = true;
+      SecondPart = Sema::ConditionError();
     } else {
       if (!Value.isInvalid()) {
         Diag(Tok, diag::err_expected_semi_for);
@@ -1660,29 +1649,28 @@ StmtResult Parser::ParseForStatement(SourceLocation *TrailingElseLoc) {
 
   // Parse the second part of the for specifier.
   getCurScope()->AddFlags(Scope::BreakScope | Scope::ContinueScope);
-  if (!ForEach && !ForRange) {
-    assert(!SecondPart.get() && "Shouldn't have a second expression yet.");
+  if (!ForEach && !ForRange && !SecondPart.isInvalid()) {
     // Parse the second part of the for specifier.
     if (Tok.is(tok::semi)) {  // for (...;;
       // no second part.
     } else if (Tok.is(tok::r_paren)) {
       // missing both semicolons.
     } else {
-      ExprResult Second;
       if (getLangOpts().CPlusPlus)
-        ParseCXXCondition(Second, SecondVar, ForLoc, true);
+        SecondPart = ParseCXXCondition(ForLoc, Sema::ConditionKind::Boolean);
       else {
-        Second = ParseExpression();
-        if (!Second.isInvalid())
-          Second = Actions.ActOnBooleanCondition(getCurScope(), ForLoc,
-                                                 Second.get());
+        ExprResult SecondExpr = ParseExpression();
+        if (SecondExpr.isInvalid())
+          SecondPart = Sema::ConditionError();
+        else
+          SecondPart =
+              Actions.ActOnCondition(getCurScope(), ForLoc, SecondExpr.get(),
+                                     Sema::ConditionKind::Boolean);
       }
-      SecondPartIsInvalid = Second.isInvalid();
-      SecondPart = Actions.MakeFullExpr(Second.get(), ForLoc);
     }
 
     if (Tok.isNot(tok::semi)) {
-      if (!SecondPartIsInvalid || SecondVar)
+      if (!SecondPart.isInvalid())
         Diag(Tok, diag::err_expected_semi_for);
       else
         // Skip until semicolon or rparen, don't consume it.
@@ -1781,8 +1769,8 @@ StmtResult Parser::ParseForStatement(SourceLocation *TrailingElseLoc) {
     return Actions.FinishCXXForRangeStmt(ForRangeStmt.get(), Body.get());
 
   return Actions.ActOnForStmt(ForLoc, T.getOpenLocation(), FirstPart.get(),
-                              SecondPart, SecondVar, ThirdPart,
-                              T.getCloseLocation(), Body.get());
+                              SecondPart, ThirdPart, T.getCloseLocation(),
+                              Body.get());
 }
 
 /// ParseGotoStatement
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 00d5651b14..8eeaef7df5 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -10092,10 +10092,10 @@ buildSingleCopyAssignRecursively(Sema &S, SourceLocation Loc, QualType T,
                                     SizeType, VK_LValue, OK_Ordinary, Loc);
 
   // Construct the loop that copies all elements of this array.
-  return S.ActOnForStmt(Loc, Loc, InitStmt, 
-                        S.MakeFullExpr(Comparison),
-                        nullptr, S.MakeFullDiscardedValueExpr(Increment),
-                        Loc, Copy.get());
+  return S.ActOnForStmt(
+      Loc, Loc, InitStmt,
+      S.ActOnCondition(nullptr, Loc, Comparison, Sema::ConditionKind::Boolean),
+      S.MakeFullDiscardedValueExpr(Increment), Loc, Copy.get());
 }
 
 static StmtResult
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 755d99d54b..f975b817e0 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -14341,7 +14341,7 @@ void Sema::DiagnoseEqualityWithExtraParens(ParenExpr *ParenE) {
     }
 }
 
-ExprResult Sema::CheckBooleanCondition(Expr *E, SourceLocation Loc) {
+ExprResult Sema::CheckBooleanCondition(SourceLocation Loc, Expr *E) {
   DiagnoseAssignmentAsCondition(E);
   if (ParenExpr *parenE = dyn_cast<ParenExpr>(E))
     DiagnoseEqualityWithExtraParens(parenE);
@@ -14371,12 +14371,26 @@ ExprResult Sema::CheckBooleanCondition(Expr *E, SourceLocation Loc) {
   return E;
 }
 
-ExprResult Sema::ActOnBooleanCondition(Scope *S, SourceLocation Loc,
-                                       Expr *SubExpr) {
+Sema::ConditionResult Sema::ActOnCondition(Scope *S, SourceLocation Loc,
+                                           Expr *SubExpr, ConditionKind CK) {
+  // Empty conditions are valid in for-statements.
   if (!SubExpr)
-    return ExprError();
+    return ConditionResult();
+
+  ExprResult Cond;
+  switch (CK) {
+  case ConditionKind::Boolean:
+    Cond = CheckBooleanCondition(Loc, SubExpr);
+    break;
+
+  case ConditionKind::Switch:
+    Cond = CheckSwitchCondition(Loc, SubExpr);
+    break;
+  }
+  if (Cond.isInvalid())
+    return ConditionError();
 
-  return CheckBooleanCondition(SubExpr, Loc);
+  return ConditionResult(nullptr, MakeFullExpr(Cond.get(), Loc));
 }
 
 namespace {
diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index d5e944fa11..f97b9c9d81 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -3054,11 +3054,21 @@ void Sema::CheckVirtualDtorCall(CXXDestructorDecl *dtor, SourceLocation Loc,
   }
 }
 
+Sema::ConditionResult Sema::ActOnConditionVariable(Decl *ConditionVar,
+                                                   SourceLocation StmtLoc,
+                                                   ConditionKind CK) {
+  ExprResult E =
+      CheckConditionVariable(cast<VarDecl>(ConditionVar), StmtLoc, CK);
+  if (E.isInvalid())
+    return ConditionError();
+  return ConditionResult(ConditionVar, MakeFullExpr(E.get(), StmtLoc));
+}
+
 /// \brief Check the use of the given variable as a C++ condition in an if,
 /// while, do-while, or switch statement.
 ExprResult Sema::CheckConditionVariable(VarDecl *ConditionVar,
                                         SourceLocation StmtLoc,
-                                        bool ConvertToBoolean) {
+                                        ConditionKind CK) {
   if (ConditionVar->isInvalidDecl())
     return ExprError();
 
@@ -3082,13 +3092,15 @@ ExprResult Sema::CheckConditionVariable(VarDecl *ConditionVar,
 
   MarkDeclRefReferenced(cast<DeclRefExpr>(Condition.get()));
 
-  if (ConvertToBoolean) {
-    Condition = CheckBooleanCondition(Condition.get(), StmtLoc);
-    if (Condition.isInvalid())
-      return ExprError();
+  switch (CK) {
+  case ConditionKind::Boolean:
+    return CheckBooleanCondition(StmtLoc, Condition.get());
+
+  case ConditionKind::Switch:
+    return CheckSwitchCondition(StmtLoc, Condition.get());
   }
 
-  return Condition;
+  llvm_unreachable("unexpected condition kind");
 }
 
 /// CheckCXXBooleanCondition - Returns true if a conversion to bool is invalid.
diff --git a/lib/Sema/SemaOpenMP.cpp b/lib/Sema/SemaOpenMP.cpp
index 5f28aa37e6..ca84b8cfed 100644
--- a/lib/Sema/SemaOpenMP.cpp
+++ b/lib/Sema/SemaOpenMP.cpp
@@ -6826,12 +6826,11 @@ OMPClause *Sema::ActOnOpenMPIfClause(OpenMPDirectiveKind NameModifier,
   if (!Condition->isValueDependent() && !Condition->isTypeDependent() &&
       !Condition->isInstantiationDependent() &&
       !Condition->containsUnexpandedParameterPack()) {
-    ExprResult Val = ActOnBooleanCondition(DSAStack->getCurScope(),
-                                           Condition->getExprLoc(), Condition);
+    ExprResult Val = CheckBooleanCondition(StartLoc, Condition);
     if (Val.isInvalid())
       return nullptr;
 
-    ValExpr = Val.get();
+    ValExpr = MakeFullExpr(Val.get()).get();
   }
 
   return new (Context) OMPIfClause(NameModifier, ValExpr, StartLoc, LParenLoc,
@@ -6846,12 +6845,11 @@ OMPClause *Sema::ActOnOpenMPFinalClause(Expr *Condition,
   if (!Condition->isValueDependent() && !Condition->isTypeDependent() &&
       !Condition->isInstantiationDependent() &&
       !Condition->containsUnexpandedParameterPack()) {
-    ExprResult Val = ActOnBooleanCondition(DSAStack->getCurScope(),
-                                           Condition->getExprLoc(), Condition);
+    ExprResult Val = CheckBooleanCondition(StartLoc, Condition);
     if (Val.isInvalid())
       return nullptr;
 
-    ValExpr = Val.get();
+    ValExpr = MakeFullExpr(Val.get()).get();
   }
 
   return new (Context) OMPFinalClause(ValExpr, StartLoc, LParenLoc, EndLoc);
diff --git a/lib/Sema/SemaStmt.cpp b/lib/Sema/SemaStmt.cpp
index 7156cd2a9a..56aa042a7b 100644
--- a/lib/Sema/SemaStmt.cpp
+++ b/lib/Sema/SemaStmt.cpp
@@ -504,39 +504,30 @@ public:
 }
 
 StmtResult
-Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar,
+Sema::ActOnIfStmt(SourceLocation IfLoc, ConditionResult Cond,
                   Stmt *thenStmt, SourceLocation ElseLoc,
                   Stmt *elseStmt) {
-  ExprResult CondResult(CondVal.release());
-
-  VarDecl *ConditionVar = nullptr;
-  if (CondVar) {
-    ConditionVar = cast<VarDecl>(CondVar);
-    CondResult = CheckConditionVariable(ConditionVar, IfLoc, true);
-    CondResult = ActOnFinishFullExpr(CondResult.get(), IfLoc);
+  auto CondVal = Cond.get();
+  if (Cond.isInvalid()) {
+    CondVal.first = nullptr;
+    CondVal.second = new (Context)
+        OpaqueValueExpr(SourceLocation(), Context.BoolTy, VK_RValue);
   }
-  Expr *ConditionExpr = CondResult.getAs<Expr>();
-  if (ConditionExpr) {
-
-    if (!Diags.isIgnored(diag::warn_comma_operator,
-                         ConditionExpr->getExprLoc()))
-      CommaVisitor(*this).Visit(ConditionExpr);
 
-    DiagnoseUnusedExprResult(thenStmt);
+  if (!Diags.isIgnored(diag::warn_comma_operator,
+                       CondVal.second->getExprLoc()))
+    CommaVisitor(*this).Visit(CondVal.second);
 
-    if (!elseStmt) {
-      DiagnoseEmptyStmtBody(ConditionExpr->getLocEnd(), thenStmt,
-                            diag::warn_empty_if_body);
-    }
+  DiagnoseUnusedExprResult(thenStmt);
 
-    DiagnoseUnusedExprResult(elseStmt);
-  } else {
-    // Create a dummy Expr for the condition for error recovery
-    ConditionExpr = new (Context) OpaqueValueExpr(SourceLocation(),
-                                                  Context.BoolTy, VK_RValue);
+  if (!elseStmt) {
+    DiagnoseEmptyStmtBody(CondVal.second->getLocEnd(), thenStmt,
+                          diag::warn_empty_if_body);
   }
 
-  return new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr,
+  DiagnoseUnusedExprResult(elseStmt);
+
+  return new (Context) IfStmt(Context, IfLoc, CondVal.first, CondVal.second,
                               thenStmt, ElseLoc, elseStmt);
 }
 
@@ -599,24 +590,7 @@ static QualType GetTypeBeforeIntegralPromotion(Expr *&expr) {
   return expr->getType();
 }
 
-StmtResult
-Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond,
-                             Decl *CondVar) {
-  ExprResult CondResult;
-
-  VarDecl *ConditionVar = nullptr;
-  if (CondVar) {
-    ConditionVar = cast<VarDecl>(CondVar);
-    CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false);
-    if (CondResult.isInvalid())
-      return StmtError();
-
-    Cond = CondResult.get();
-  }
-
-  if (!Cond)
-    return StmtError();
-
+ExprResult Sema::CheckSwitchCondition(SourceLocation SwitchLoc, Expr *Cond) {
   class SwitchConvertDiagnoser : public ICEConvertDiagnoser {
     Expr *Cond;
 
@@ -664,24 +638,24 @@ Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond,
     }
   } SwitchDiagnoser(Cond);
 
-  CondResult =
+  ExprResult CondResult =
       PerformContextualImplicitConversion(SwitchLoc, Cond, SwitchDiagnoser);
-  if (CondResult.isInvalid()) return StmtError();
-  Cond = CondResult.get();
+  if (CondResult.isInvalid())
+    return ExprError();
 
   // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
-  CondResult = UsualUnaryConversions(Cond);
-  if (CondResult.isInvalid()) return StmtError();
-  Cond = CondResult.get();
+  return UsualUnaryConversions(CondResult.get());
+}
 
-  CondResult = ActOnFinishFullExpr(Cond, SwitchLoc);
-  if (CondResult.isInvalid())
+StmtResult
+Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, ConditionResult Cond) {
+  if (Cond.isInvalid())
     return StmtError();
-  Cond = CondResult.get();
 
   getCurFunction()->setHasBranchIntoScope();
 
-  SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond);
+  SwitchStmt *SS =
+      new (Context) SwitchStmt(Context, Cond.get().first, Cond.get().second);
   getCurFunction()->SwitchStack.push_back(SS);
   return SS;
 }
@@ -1242,27 +1216,17 @@ Sema::DiagnoseAssignmentEnum(QualType DstType, QualType SrcType,
     }
 }
 
-StmtResult
-Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond,
-                     Decl *CondVar, Stmt *Body) {
-  ExprResult CondResult(Cond.release());
-
-  VarDecl *ConditionVar = nullptr;
-  if (CondVar) {
-    ConditionVar = cast<VarDecl>(CondVar);
-    CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true);
-    CondResult = ActOnFinishFullExpr(CondResult.get(), WhileLoc);
-    if (CondResult.isInvalid())
-      return StmtError();
-  }
-  Expr *ConditionExpr = CondResult.get();
-  if (!ConditionExpr)
+StmtResult Sema::ActOnWhileStmt(SourceLocation WhileLoc, ConditionResult Cond,
+                                Stmt *Body) {
+  if (Cond.isInvalid())
     return StmtError();
-  CheckBreakContinueBinding(ConditionExpr);
 
-  if (ConditionExpr &&
-      !Diags.isIgnored(diag::warn_comma_operator, ConditionExpr->getExprLoc()))
-    CommaVisitor(*this).Visit(ConditionExpr);
+  auto CondVal = Cond.get();
+  CheckBreakContinueBinding(CondVal.second);
+
+  if (CondVal.second &&
+      !Diags.isIgnored(diag::warn_comma_operator, CondVal.second->getExprLoc()))
+    CommaVisitor(*this).Visit(CondVal.second);
 
   DiagnoseUnusedExprResult(Body);
 
@@ -1270,7 +1234,7 @@ Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond,
     getCurCompoundScope().setHasEmptyLoopBodies();
 
   return new (Context)
-      WhileStmt(Context, ConditionVar, ConditionExpr, Body, WhileLoc);
+      WhileStmt(Context, CondVal.first, CondVal.second, Body, WhileLoc);
 }
 
 StmtResult
@@ -1280,7 +1244,7 @@ Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
   assert(Cond && "ActOnDoStmt(): missing expression");
 
   CheckBreakContinueBinding(Cond);
-  ExprResult CondResult = CheckBooleanCondition(Cond, DoLoc);
+  ExprResult CondResult = CheckBooleanCondition(DoLoc, Cond);
   if (CondResult.isInvalid())
     return StmtError();
   Cond = CondResult.get();
@@ -1644,11 +1608,13 @@ void Sema::CheckBreakContinueBinding(Expr *E) {
   }
 }
 
-StmtResult
-Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
-                   Stmt *First, FullExprArg second, Decl *secondVar,
-                   FullExprArg third,
-                   SourceLocation RParenLoc, Stmt *Body) {
+StmtResult Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
+                              Stmt *First, ConditionResult Second,
+                              FullExprArg third, SourceLocation RParenLoc,
+                              Stmt *Body) {
+  if (Second.isInvalid())
+    return StmtError();
+
   if (!getLangOpts().CPlusPlus) {
     if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) {
       // C99 6.8.5p3: The declaration part of a 'for' statement shall only
@@ -1666,26 +1632,17 @@ Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
     }
   }
 
-  CheckBreakContinueBinding(second.get());
+  CheckBreakContinueBinding(Second.get().second);
   CheckBreakContinueBinding(third.get());
 
-  CheckForLoopConditionalStatement(*this, second.get(), third.get(), Body);
+  CheckForLoopConditionalStatement(*this, Second.get().second, third.get(),
+                                   Body);
   CheckForRedundantIteration(*this, third.get(), Body);
 
-  ExprResult SecondResult(second.release());
-  VarDecl *ConditionVar = nullptr;
-  if (secondVar) {
-    ConditionVar = cast<VarDecl>(secondVar);
-    SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true);
-    SecondResult = ActOnFinishFullExpr(SecondResult.get(), ForLoc);
-    if (SecondResult.isInvalid())
-      return StmtError();
-  }
-
-  if (SecondResult.get() &&
+  if (Second.get().second &&
       !Diags.isIgnored(diag::warn_comma_operator,
-                       SecondResult.get()->getExprLoc()))
-    CommaVisitor(*this).Visit(SecondResult.get());
+                       Second.get().second->getExprLoc()))
+    CommaVisitor(*this).Visit(Second.get().second);
 
   Expr *Third  = third.release().getAs<Expr>();
 
@@ -1696,8 +1653,9 @@ Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
   if (isa<NullStmt>(Body))
     getCurCompoundScope().setHasEmptyLoopBodies();
 
-  return new (Context) ForStmt(Context, First, SecondResult.get(), ConditionVar,
-                               Third, Body, ForLoc, LParenLoc, RParenLoc);
+  return new (Context)
+      ForStmt(Context, First, Second.get().second, Second.get().first, Third,
+              Body, ForLoc, LParenLoc, RParenLoc);
 }
 
 /// In an Objective C collection iteration statement:
@@ -2384,8 +2342,10 @@ Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation CoawaitLoc,
     // Build and check __begin != __end expression.
     NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal,
                            BeginRef.get(), EndRef.get());
-    NotEqExpr = ActOnBooleanCondition(S, ColonLoc, NotEqExpr.get());
-    NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get());
+    if (!NotEqExpr.isInvalid())
+      NotEqExpr = CheckBooleanCondition(ColonLoc, NotEqExpr.get());
+    if (!NotEqExpr.isInvalid())
+      NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get());
     if (NotEqExpr.isInvalid()) {
       Diag(RangeLoc, diag::note_for_range_invalid_iterator)
         << RangeLoc << 0 << BeginRangeRef.get()->getType();
diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index 4bdd9e548a..5814197a7a 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -410,6 +410,14 @@ public:
     return D;
   }
 
+  /// \brief Transform the specified condition.
+  ///
+  /// By default, this transforms the variable and expression and rebuilds
+  /// the condition.
+  Sema::ConditionResult TransformCondition(SourceLocation Loc, VarDecl *Var,
+                                           Expr *Expr,
+                                           Sema::ConditionKind Kind);
+
   /// \brief Transform the attributes associated with the given declaration and
   /// place them on the new declaration.
   ///
@@ -1166,10 +1174,9 @@ public:
   ///
   /// By default, performs semantic analysis to build the new statement.
   /// Subclasses may override this routine to provide different behavior.
-  StmtResult RebuildIfStmt(SourceLocation IfLoc, Sema::FullExprArg Cond,
-                           VarDecl *CondVar, Stmt *Then,
-                           SourceLocation ElseLoc, Stmt *Else) {
-    return getSema().ActOnIfStmt(IfLoc, Cond, CondVar, Then, ElseLoc, Else);
+  StmtResult RebuildIfStmt(SourceLocation IfLoc, Sema::ConditionResult Cond,
+                           Stmt *Then, SourceLocation ElseLoc, Stmt *Else) {
+    return getSema().ActOnIfStmt(IfLoc, Cond, Then, ElseLoc, Else);
   }
 
   /// \brief Start building a new switch statement.
@@ -1177,9 +1184,8 @@ public:
   /// By default, performs semantic analysis to build the new statement.
   /// Subclasses may override this routine to provide different behavior.
   StmtResult RebuildSwitchStmtStart(SourceLocation SwitchLoc,
-                                    Expr *Cond, VarDecl *CondVar) {
-    return getSema().ActOnStartOfSwitchStmt(SwitchLoc, Cond,
-                                            CondVar);
+                                    Sema::ConditionResult Cond) {
+    return getSema().ActOnStartOfSwitchStmt(SwitchLoc, Cond);
   }
 
   /// \brief Attach the body to the switch statement.
@@ -1195,9 +1201,9 @@ public:
   ///
   /// By default, performs semantic analysis to build the new statement.
   /// Subclasses may override this routine to provide different behavior.
-  StmtResult RebuildWhileStmt(SourceLocation WhileLoc, Sema::FullExprArg Cond,
-                              VarDecl *CondVar, Stmt *Body) {
-    return getSema().ActOnWhileStmt(WhileLoc, Cond, CondVar, Body);
+  StmtResult RebuildWhileStmt(SourceLocation WhileLoc,
+                              Sema::ConditionResult Cond, Stmt *Body) {
+    return getSema().ActOnWhileStmt(WhileLoc, Cond, Body);
   }
 
   /// \brief Build a new do-while statement.
@@ -1216,11 +1222,11 @@ public:
   /// By default, performs semantic analysis to build the new statement.
   /// Subclasses may override this routine to provide different behavior.
   StmtResult RebuildForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
-                            Stmt *Init, Sema::FullExprArg Cond,
-                            VarDecl *CondVar, Sema::FullExprArg Inc,
-                            SourceLocation RParenLoc, Stmt *Body) {
+                            Stmt *Init, Sema::ConditionResult Cond,
+                            Sema::FullExprArg Inc, SourceLocation RParenLoc,
+                            Stmt *Body) {
     return getSema().ActOnForStmt(ForLoc, LParenLoc, Init, Cond,
-                                  CondVar, Inc, RParenLoc, Body);
+                                  Inc, RParenLoc, Body);
   }
 
   /// \brief Build a new goto statement.
@@ -3357,6 +3363,31 @@ bool TreeTransform<Derived>::TransformExprs(Expr *const *Inputs,
   return false;
 }
 
+template <typename Derived>
+Sema::ConditionResult TreeTransform<Derived>::TransformCondition(
+    SourceLocation Loc, VarDecl *Var, Expr *Expr, Sema::ConditionKind Kind) {
+  if (Var) {
+    VarDecl *ConditionVar = cast_or_null<VarDecl>(
+        getDerived().TransformDefinition(Var->getLocation(), Var));
+
+    if (!ConditionVar)
+      return Sema::ConditionError();
+
+    return getSema().ActOnConditionVariable(ConditionVar, Loc, Kind);
+  }
+
+  if (Expr) {
+    ExprResult CondExpr = getDerived().TransformExpr(Expr);
+
+    if (CondExpr.isInvalid())
+      return Sema::ConditionError();
+
+    return getSema().ActOnCondition(nullptr, Loc, CondExpr.get(), Kind);
+  }
+
+  return Sema::ConditionResult();
+}
+
 template<typename Derived>
 NestedNameSpecifierLoc
 TreeTransform<Derived>::TransformNestedNameSpecifierLoc(
@@ -4962,8 +4993,8 @@ bool TreeTransform<Derived>::TransformExceptionSpec(
     if (NoexceptExpr.isInvalid())
       return true;
 
-    NoexceptExpr = getSema().CheckBooleanCondition(
-        NoexceptExpr.get(), NoexceptExpr.get()->getLocStart());
+    // FIXME: This is bogus, a noexcept expression is not a condition.
+    NoexceptExpr = getSema().CheckBooleanCondition(Loc, NoexceptExpr.get());
     if (NoexceptExpr.isInvalid())
       return true;
 
@@ -6195,35 +6226,10 @@ template<typename Derived>
 StmtResult
 TreeTransform<Derived>::TransformIfStmt(IfStmt *S) {
   // Transform the condition
-  ExprResult Cond;
-  VarDecl *ConditionVar = nullptr;
-  if (S->getConditionVariable()) {
-    ConditionVar
-      = cast_or_null<VarDecl>(
-                   getDerived().TransformDefinition(
-                                      S->getConditionVariable()->getLocation(),
-                                                    S->getConditionVariable()));
-    if (!ConditionVar)
-      return StmtError();
-  } else {
-    Cond = getDerived().TransformExpr(S->getCond());
-
-    if (Cond.isInvalid())
-      return StmtError();
-
-    // Convert the condition to a boolean value.
-    if (S->getCond()) {
-      ExprResult CondE = getSema().ActOnBooleanCondition(nullptr, S->getIfLoc(),
-                                                         Cond.get());
-      if (CondE.isInvalid())
-        return StmtError();
-
-      Cond = CondE.get();
-    }
-  }
-
-  Sema::FullExprArg FullCond(getSema().MakeFullExpr(Cond.get(), S->getIfLoc()));
-  if (!S->getConditionVariable() && S->getCond() && !FullCond.get())
+  Sema::ConditionResult Cond = getDerived().TransformCondition(
+      S->getIfLoc(), S->getConditionVariable(), S->getCond(),
+      Sema::ConditionKind::Boolean);
+  if (Cond.isInvalid())
     return StmtError();
 
   // Transform the "then" branch.
@@ -6237,14 +6243,12 @@ TreeTransform<Derived>::TransformIfStmt(IfStmt *S) {
     return StmtError();
 
   if (!getDerived().AlwaysRebuild() &&
-      FullCond.get() == S->getCond() &&
-      ConditionVar == S->getConditionVariable() &&
+      Cond.get() == std::make_pair(S->getConditionVariable(), S->getCond()) &&
       Then.get() == S->getThen() &&
       Else.get() == S->getElse())
     return S;
 
-  return getDerived().RebuildIfStmt(S->getIfLoc(), FullCond, ConditionVar,
-                                    Then.get(),
+  return getDerived().RebuildIfStmt(S->getIfLoc(), Cond, Then.get(),
                                     S->getElseLoc(), Else.get());
 }
 
@@ -6252,27 +6256,15 @@ template<typename Derived>
 StmtResult
 TreeTransform<Derived>::TransformSwitchStmt(SwitchStmt *S) {
   // Transform the condition.
-  ExprResult Cond;
-  VarDecl *ConditionVar = nullptr;
-  if (S->getConditionVariable()) {
-    ConditionVar
-      = cast_or_null<VarDecl>(
-                   getDerived().TransformDefinition(
-                                      S->getConditionVariable()->getLocation(),
-                                                    S->getConditionVariable()));
-    if (!ConditionVar)
-      return StmtError();
-  } else {
-    Cond = getDerived().TransformExpr(S->getCond());
-
-    if (Cond.isInvalid())
-      return StmtError();
-  }
+  Sema::ConditionResult Cond = getDerived().TransformCondition(
+      S->getSwitchLoc(), S->getConditionVariable(), S->getCond(),
+      Sema::ConditionKind::Switch);
+  if (Cond.isInvalid())
+    return StmtError();
 
   // Rebuild the switch statement.
   StmtResult Switch
-    = getDerived().RebuildSwitchStmtStart(S->getSwitchLoc(), Cond.get(),
-                                          ConditionVar);
+    = getDerived().RebuildSwitchStmtStart(S->getSwitchLoc(), Cond);
   if (Switch.isInvalid())
     return StmtError();
 
@@ -6290,36 +6282,10 @@ template<typename Derived>
 StmtResult
 TreeTransform<Derived>::TransformWhileStmt(WhileStmt *S) {
   // Transform the condition
-  ExprResult Cond;
-  VarDecl *ConditionVar = nullptr;
-  if (S->getConditionVariable()) {
-    ConditionVar
-      = cast_or_null<VarDecl>(
-                   getDerived().TransformDefinition(
-                                      S->getConditionVariable()->getLocation(),
-                                                    S->getConditionVariable()));
-    if (!ConditionVar)
-      return StmtError();
-  } else {
-    Cond = getDerived().TransformExpr(S->getCond());
-
-    if (Cond.isInvalid())
-      return StmtError();
-
-    if (S->getCond()) {
-      // Convert the condition to a boolean value.
-      ExprResult CondE = getSema().ActOnBooleanCondition(nullptr,
-                                                         S->getWhileLoc(),
-                                                         Cond.get());
-      if (CondE.isInvalid())
-        return StmtError();
-      Cond = CondE;
-    }
-  }
-
-  Sema::FullExprArg FullCond(
-      getSema().MakeFullExpr(Cond.get(), S->getWhileLoc()));
-  if (!S->getConditionVariable() && S->getCond() && !FullCond.get())
+  Sema::ConditionResult Cond = getDerived().TransformCondition(
+      S->getWhileLoc(), S->getConditionVariable(), S->getCond(),
+      Sema::ConditionKind::Boolean);
+  if (Cond.isInvalid())
     return StmtError();
 
   // Transform the body
@@ -6328,13 +6294,11 @@ TreeTransform<Derived>::TransformWhileStmt(WhileStmt *S) {
     return StmtError();
 
   if (!getDerived().AlwaysRebuild() &&
-      FullCond.get() == S->getCond() &&
-      ConditionVar == S->getConditionVariable() &&
+      Cond.get() == std::make_pair(S->getConditionVariable(), S->getCond()) &&
       Body.get() == S->getBody())
     return Owned(S);
 
-  return getDerived().RebuildWhileStmt(S->getWhileLoc(), FullCond,
-                                       ConditionVar, Body.get());
+  return getDerived().RebuildWhileStmt(S->getWhileLoc(), Cond, Body.get());
 }
 
 template<typename Derived>
@@ -6374,37 +6338,10 @@ TreeTransform<Derived>::TransformForStmt(ForStmt *S) {
     getSema().ActOnOpenMPLoopInitialization(S->getForLoc(), Init.get());
 
   // Transform the condition
-  ExprResult Cond;
-  VarDecl *ConditionVar = nullptr;
-  if (S->getConditionVariable()) {
-    ConditionVar
-      = cast_or_null<VarDecl>(
-                   getDerived().TransformDefinition(
-                                      S->getConditionVariable()->getLocation(),
-                                                    S->getConditionVariable()));
-    if (!ConditionVar)
-      return StmtError();
-  } else {
-    Cond = getDerived().TransformExpr(S->getCond());
-
-    if (Cond.isInvalid())
-      return StmtError();
-
-    if (S->getCond()) {
-      // Convert the condition to a boolean value.
-      ExprResult CondE = getSema().ActOnBooleanCondition(nullptr,
-                                                         S->getForLoc(),
-                                                         Cond.get());
-      if (CondE.isInvalid())
-        return StmtError();
-
-      Cond = CondE.get();
-    }
-  }
-
-  Sema::FullExprArg FullCond(
-      getSema().MakeFullExpr(Cond.get(), S->getForLoc()));
-  if (!S->getConditionVariable() && S->getCond() && !FullCond.get())
+  Sema::ConditionResult Cond = getDerived().TransformCondition(
+      S->getForLoc(), S->getConditionVariable(), S->getCond(),
+      Sema::ConditionKind::Boolean);
+  if (Cond.isInvalid())
     return StmtError();
 
   // Transform the increment
@@ -6423,14 +6360,14 @@ TreeTransform<Derived>::TransformForStmt(ForStmt *S) {
 
   if (!getDerived().AlwaysRebuild() &&
       Init.get() == S->getInit() &&
-      FullCond.get() == S->getCond() &&
+      Cond.get() == std::make_pair(S->getConditionVariable(), S->getCond()) &&
       Inc.get() == S->getInc() &&
       Body.get() == S->getBody())
     return S;
 
   return getDerived().RebuildForStmt(S->getForLoc(), S->getLParenLoc(),
-                                     Init.get(), FullCond, ConditionVar,
-                                     FullInc, S->getRParenLoc(), Body.get());
+                                     Init.get(), Cond, FullInc,
+                                     S->getRParenLoc(), Body.get());
 }
 
 template<typename Derived>
@@ -6924,7 +6861,7 @@ TreeTransform<Derived>::TransformCXXForRangeStmt(CXXForRangeStmt *S) {
   if (Cond.isInvalid())
     return StmtError();
   if (Cond.get())
-    Cond = SemaRef.CheckBooleanCondition(Cond.get(), S->getColonLoc());
+    Cond = SemaRef.CheckBooleanCondition(S->getColonLoc(), Cond.get());
   if (Cond.isInvalid())
     return StmtError();
   if (Cond.get())
diff --git a/test/FixIt/fixit-vexing-parse.cpp b/test/FixIt/fixit-vexing-parse.cpp
index 0232f5dbb0..71d3eff532 100644
--- a/test/FixIt/fixit-vexing-parse.cpp
+++ b/test/FixIt/fixit-vexing-parse.cpp
@@ -60,7 +60,7 @@ namespace N {
     VO m(int (*p)[4]);
 
     // Don't emit warning and fixit because direct initializer is not permitted here.
-    if (int n(int())){} // expected-error {{function type is not allowed here}} expected-error {{condition must have an initializer}}
+    if (int n(int())){} // expected-error {{function type is not allowed here}}
 
     // CHECK: fix-it:"{{.*}}":{66:8-66:10}:" = {}"
     U u(); // expected-warning {{function declaration}} expected-note {{replace parentheses with an initializer}}
diff --git a/test/Parser/cxx0x-condition.cpp b/test/Parser/cxx0x-condition.cpp
index 8b64bcf127..071e09e415 100644
--- a/test/Parser/cxx0x-condition.cpp
+++ b/test/Parser/cxx0x-condition.cpp
@@ -23,9 +23,9 @@ void f() {
 
   if (S b(a)) {} // expected-error {{variable declaration in condition cannot have a parenthesized initializer}}
 
-  if (S b(n)) {} // expected-error {{a function type is not allowed here}} expected-error {{must have an initializer}}
+  if (S b(n)) {} // expected-error {{a function type is not allowed here}}
   if (S b(n) = 0) {} // expected-error {{a function type is not allowed here}}
-  if (S b(n) == 0) {} // expected-error {{a function type is not allowed here}} expected-error {{did you mean '='?}}
+  if (S b(n) == 0) {} // expected-error {{a function type is not allowed here}}
 
   S s(a);
   if (S{s}) {} // ok
diff --git a/test/SemaCXX/crashes.cpp b/test/SemaCXX/crashes.cpp
index 926d13ab45..a80587d840 100644
--- a/test/SemaCXX/crashes.cpp
+++ b/test/SemaCXX/crashes.cpp
@@ -105,8 +105,7 @@ namespace PR9026 {
 namespace PR10270 {
   template<typename T> class C;
   template<typename T> void f() {
-    if (C<T> == 1) // expected-error{{expected unqualified-id}} \
-                   // expected-error{{invalid '==' at end of declaration}}
+    if (C<T> == 1) // expected-error{{expected unqualified-id}}
       return;
   }
 }
diff --git a/test/SemaCXX/for-range-examples.cpp b/test/SemaCXX/for-range-examples.cpp
index 83023e3110..08a9982c63 100644
--- a/test/SemaCXX/for-range-examples.cpp
+++ b/test/SemaCXX/for-range-examples.cpp
@@ -176,9 +176,9 @@ namespace test4 {
 
     // Make sure these don't crash. Better diagnostics would be nice.
     for (: {1, 2, 3}) {} // expected-error {{expected expression}} expected-error {{expected ';'}}
-    for (1 : {1, 2, 3}) {} // expected-error {{must declare a variable}} expected-warning {{result unused}}
+    for (1 : {1, 2, 3}) {} // expected-error {{must declare a variable}}
     for (+x : {1, 2, 3}) {} // expected-error {{undeclared identifier}} expected-error {{expected ';'}}
-    for (+y : {1, 2, 3}) {} // expected-error {{must declare a variable}} expected-warning {{result unused}}
+    for (+y : {1, 2, 3}) {} // expected-error {{must declare a variable}}
   }
 }
 
diff --git a/test/SemaObjCXX/foreach.mm b/test/SemaObjCXX/foreach.mm
index d1302c19a5..99f5d0ce55 100644
--- a/test/SemaObjCXX/foreach.mm
+++ b/test/SemaObjCXX/foreach.mm
@@ -6,10 +6,8 @@
 void f(NSArray *a) {
     id keys;
     for (int i : a); // expected-error{{selector element type 'int' is not a valid object}} 
-    for ((id)2 : a);  // expected-error {{for range declaration must declare a variable}} \
-                      // expected-warning {{expression result unused}}
-    for (2 : a); // expected-error {{for range declaration must declare a variable}} \
-                 // expected-warning {{expression result unused}}
+    for ((id)2 : a);  // expected-error {{for range declaration must declare a variable}}
+    for (2 : a); // expected-error {{for range declaration must declare a variable}}
   
   for (id thisKey : keys);
 
@@ -65,8 +63,7 @@ int main ()
 @end
 void test2(NSObject<NSFastEnumeration> *collection) {
   Test2 *obj;
-  for (obj.prop : collection) { // expected-error {{for range declaration must declare a variable}} \
-                                // expected-warning {{property access result unused - getters should not be used for side effects}}
+  for (obj.prop : collection) { // expected-error {{for range declaration must declare a variable}}
   }
 }