[AST] Add RecoveryExpr to retain expressions on semantic errors

Normally clang avoids creating expressions when it encounters semantic
errors, even if the parser knows which expression to produce.

This works well for the compiler. However, this is not ideal for
source-level tools that have to deal with broken code, e.g. clangd is
not able to provide navigation features even for names that compiler
knows how to resolve.

The new RecoveryExpr aims to capture the minimal set of information
useful for the tools that need to deal with incorrect code:

source range of the expression being dropped,
subexpressions of the expression.
We aim to make constructing RecoveryExprs as simple as possible to
ensure writing code to avoid dropping expressions is easy.

Producing RecoveryExprs can result in new code paths being taken in the
frontend. In particular, clang can produce some new diagnostics now and
we aim to suppress bogus ones based on Expr::containsErrors.

We deliberately produce RecoveryExprs only in the parser for now to
minimize the code affected by this patch. Producing RecoveryExprs in
Sema potentially allows to preserve more information (e.g. type of an
expression), but also results in more code being affected. E.g.
SFINAE checks will have to take presence of RecoveryExprs into account.

Initial implementation only works in C++ mode, as it relies on compiler
postponing diagnostics on dependent expressions. C and ObjC often do not
do this, so they require more work to make sure we do not produce too
many bogus diagnostics on the new expressions.

See documentation of RecoveryExpr for more details.

original patch from Ilya
This change is based on https://reviews.llvm.org/D61722

Reviewers: sammccall, rsmith

Reviewed By: sammccall, rsmith

Tags: #clang

Differential Revision: https://reviews.llvm.org/D69330

diff --git a/clang/include/clang/AST/ComputeDependence.h b/clang/include/clang/AST/ComputeDependence.h
index 69ccb6c..02f8264 100644 (file)
--- a/clang/include/clang/AST/ComputeDependence.h
+++ b/clang/include/clang/AST/ComputeDependence.h
@@ -45,6 +45,7 @@ class ExtVectorElementExpr;
 class BlockExpr;
 class AsTypeExpr;
 class DeclRefExpr;
+class RecoveryExpr;
 class CXXRewrittenBinaryOperator;
 class CXXStdInitializerListExpr;
 class CXXTypeidExpr;
@@ -122,6 +123,7 @@ ExprDependence computeDependence(ExtVectorElementExpr *E);
 ExprDependence computeDependence(BlockExpr *E);
 ExprDependence computeDependence(AsTypeExpr *E);
 ExprDependence computeDependence(DeclRefExpr *E, const ASTContext &Ctx);
+ExprDependence computeDependence(RecoveryExpr *E);
 ExprDependence computeDependence(CXXRewrittenBinaryOperator *E);
 ExprDependence computeDependence(CXXStdInitializerListExpr *E);
 ExprDependence computeDependence(CXXTypeidExpr *E);

diff --git a/clang/include/clang/AST/Expr.h b/clang/include/clang/AST/Expr.h
index f960fbd..e27d7f0 100644 (file)
--- a/clang/include/clang/AST/Expr.h
+++ b/clang/include/clang/AST/Expr.h
@@ -5911,6 +5911,69 @@ public:
   }
 
 };
+
+/// Frontend produces RecoveryExprs on semantic errors that prevent creating
+/// other well-formed expressions. E.g. when type-checking of a binary operator
+/// fails, we cannot produce a BinaryOperator expression. Instead, we can choose
+/// to produce a recovery expression storing left and right operands.
+///
+/// RecoveryExpr does not have any semantic meaning in C++, it is only useful to
+/// preserve expressions in AST that would otherwise be dropped. It captures
+/// subexpressions of some expression that we could not construct and source
+/// range covered by the expression.
+///
+/// For now, RecoveryExpr is type-, value- and instantiation-dependent to take
+/// advantage of existing machinery to deal with dependent code in C++, e.g.
+/// RecoveryExpr is preserved in `decltype(<broken-expr>)` as part of the
+/// `DependentDecltypeType`. In addition to that, clang does not report most
+/// errors on dependent expressions, so we get rid of bogus errors for free.
+/// However, note that unlike other dependent expressions, RecoveryExpr can be
+/// produced in non-template contexts.
+///
+/// One can also reliably suppress all bogus errors on expressions containing
+/// recovery expressions by examining results of Expr::containsErrors().
+class RecoveryExpr final : public Expr,
+                           private llvm::TrailingObjects<RecoveryExpr, Expr *> {
+public:
+  static RecoveryExpr *Create(ASTContext &Ctx, SourceLocation BeginLoc,
+                              SourceLocation EndLoc, ArrayRef<Expr *> SubExprs);
+  static RecoveryExpr *CreateEmpty(ASTContext &Ctx, unsigned NumSubExprs);
+
+  ArrayRef<Expr *> subExpressions() {
+    auto *B = getTrailingObjects<Expr *>();
+    return llvm::makeArrayRef(B, B + NumExprs);
+  }
+
+  ArrayRef<const Expr *> subExpressions() const {
+    return const_cast<RecoveryExpr *>(this)->subExpressions();
+  }
+
+  child_range children() {
+    Stmt **B = reinterpret_cast<Stmt **>(getTrailingObjects<Expr *>());
+    return child_range(B, B + NumExprs);
+  }
+
+  SourceLocation getBeginLoc() const { return BeginLoc; }
+  SourceLocation getEndLoc() const { return EndLoc; }
+
+  static bool classof(const Stmt *T) {
+    return T->getStmtClass() == RecoveryExprClass;
+  }
+
+private:
+  RecoveryExpr(ASTContext &Ctx, SourceLocation BeginLoc, SourceLocation EndLoc,
+               ArrayRef<Expr *> SubExprs);
+  RecoveryExpr(EmptyShell Empty) : Expr(RecoveryExprClass, Empty) {}
+
+  size_t numTrailingObjects(OverloadToken<Stmt *>) const { return NumExprs; }
+
+  SourceLocation BeginLoc, EndLoc;
+  unsigned NumExprs;
+  friend TrailingObjects;
+  friend class ASTStmtReader;
+  friend class ASTStmtWriter;
+};
+
 } // end namespace clang
 
 #endif // LLVM_CLANG_AST_EXPR_H

diff --git a/clang/include/clang/AST/RecursiveASTVisitor.h b/clang/include/clang/AST/RecursiveASTVisitor.h
index 4bd489f..2f59856 100644 (file)
--- a/clang/include/clang/AST/RecursiveASTVisitor.h
+++ b/clang/include/clang/AST/RecursiveASTVisitor.h
@@ -2668,6 +2668,7 @@ DEF_TRAVERSE_STMT(CXXRewrittenBinaryOperator, {
 })
 DEF_TRAVERSE_STMT(OpaqueValueExpr, {})
 DEF_TRAVERSE_STMT(TypoExpr, {})
+DEF_TRAVERSE_STMT(RecoveryExpr, {})
 DEF_TRAVERSE_STMT(CUDAKernelCallExpr, {})
 
 // These operators (all of them) do not need any action except

diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def
index 4ba8c76..6152e22 100644 (file)
--- a/clang/include/clang/Basic/LangOptions.def
+++ b/clang/include/clang/Basic/LangOptions.def
@@ -148,6 +148,8 @@ LANGOPT(RelaxedTemplateTemplateArgs, 1, 0, "C++17 relaxed matching of template t
 
 LANGOPT(DoubleSquareBracketAttributes, 1, 0, "'[[]]' attributes extension for all language standard modes")
 
+COMPATIBLE_LANGOPT(RecoveryAST, 1, 0, "Preserve expressions in AST when encountering errors")
+
 BENIGN_LANGOPT(ThreadsafeStatics , 1, 1, "thread-safe static initializers")
 LANGOPT(POSIXThreads      , 1, 0, "POSIX thread support")
 LANGOPT(Blocks            , 1, 0, "blocks extension to C")

diff --git a/clang/include/clang/Basic/StmtNodes.td b/clang/include/clang/Basic/StmtNodes.td
index a617ab8..478179d 100644 (file)
--- a/clang/include/clang/Basic/StmtNodes.td
+++ b/clang/include/clang/Basic/StmtNodes.td
@@ -195,6 +195,7 @@ def ConvertVectorExpr : StmtNode<Expr>;
 def BlockExpr : StmtNode<Expr>;
 def OpaqueValueExpr : StmtNode<Expr>;
 def TypoExpr : StmtNode<Expr>;
+def RecoveryExpr : StmtNode<Expr>;
 def BuiltinBitCastExpr : StmtNode<ExplicitCastExpr>;
 
 // Microsoft Extensions.

diff --git a/clang/include/clang/Driver/CC1Options.td b/clang/include/clang/Driver/CC1Options.td
index 66a443b..a409233 100644 (file)
--- a/clang/include/clang/Driver/CC1Options.td
+++ b/clang/include/clang/Driver/CC1Options.td
@@ -566,6 +566,11 @@ def fno_concept_satisfaction_caching : Flag<["-"],
                                             "fno-concept-satisfaction-caching">,
   HelpText<"Disable satisfaction caching for C++2a Concepts.">;
 
+def frecovery_ast : Flag<["-"], "frecovery-ast">,
+  HelpText<"Preserve expressions in AST rather than dropping them when "
+           "encountering semantic errors">;
+def fno_recovery_ast : Flag<["-"], "fno-recovery-ast">;
+
 let Group = Action_Group in {
 
 def Eonly : Flag<["-"], "Eonly">,

diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 9f487e3..4eaf09a 100644 (file)
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -3885,6 +3885,10 @@ public:
   void DiagnoseAmbiguousLookup(LookupResult &Result);
   //@}
 
+  /// Attempts to produce a RecoveryExpr after some AST node cannot be created.
+  ExprResult CreateRecoveryExpr(SourceLocation Begin, SourceLocation End,
+                                ArrayRef<Expr *> SubExprs);
+
   ObjCInterfaceDecl *getObjCInterfaceDecl(IdentifierInfo *&Id,
                                           SourceLocation IdLoc,
                                           bool TypoCorrection = false);

diff --git a/clang/include/clang/Serialization/ASTBitCodes.h b/clang/include/clang/Serialization/ASTBitCodes.h
index b28deaa..f185c1a 100644 (file)
--- a/clang/include/clang/Serialization/ASTBitCodes.h
+++ b/clang/include/clang/Serialization/ASTBitCodes.h
@@ -1634,6 +1634,9 @@ namespace serialization {
       /// An AtomicExpr record.
       EXPR_ATOMIC,
 
+      /// A RecoveryExpr record.
+      EXPR_RECOVERY,
+
       // Objective-C
 
       /// An ObjCStringLiteral record.

diff --git a/clang/lib/AST/ComputeDependence.cpp b/clang/lib/AST/ComputeDependence.cpp
index 20b2837..a6ccf9a 100644 (file)
--- a/clang/lib/AST/ComputeDependence.cpp
+++ b/clang/lib/AST/ComputeDependence.cpp
@@ -456,6 +456,15 @@ ExprDependence clang::computeDependence(DeclRefExpr *E, const ASTContext &Ctx) {
   return Deps;
 }
 
+ExprDependence clang::computeDependence(RecoveryExpr *E) {
+  // FIXME: drop type+value+instantiation once Error is sufficient to suppress
+  // bogus dianostics.
+  auto D = ExprDependence::TypeValueInstantiation | ExprDependence::Error;
+  for (auto *S : E->subExpressions())
+    D |= S->getDependence();
+  return D;
+}
+
 ExprDependence clang::computeDependence(PredefinedExpr *E) {
   return toExprDependence(E->getType()->getDependence()) &
          ~ExprDependence::UnexpandedPack;

diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index a2a024a..b964eb6 100644 (file)
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -2375,6 +2375,7 @@ bool Expr::isUnusedResultAWarning(const Expr *&WarnE, SourceLocation &Loc,
   // If we don't know precisely what we're looking at, let's not warn.
   case UnresolvedLookupExprClass:
   case CXXUnresolvedConstructExprClass:
+  case RecoveryExprClass:
     return false;
 
   case CXXTemporaryObjectExprClass:
@@ -3227,6 +3228,7 @@ bool Expr::HasSideEffects(const ASTContext &Ctx,
   case SubstNonTypeTemplateParmPackExprClass:
   case FunctionParmPackExprClass:
   case TypoExprClass:
+  case RecoveryExprClass:
   case CXXFoldExprClass:
     llvm_unreachable("shouldn't see dependent / unresolved nodes here");
 
@@ -4467,3 +4469,30 @@ QualType OMPArraySectionExpr::getBaseOriginalType(const Expr *Base) {
   }
   return OriginalTy;
 }
+
+RecoveryExpr::RecoveryExpr(ASTContext &Ctx, SourceLocation BeginLoc,
+                           SourceLocation EndLoc, ArrayRef<Expr *> SubExprs)
+    : Expr(RecoveryExprClass, Ctx.DependentTy, VK_LValue, OK_Ordinary),
+      BeginLoc(BeginLoc), EndLoc(EndLoc), NumExprs(SubExprs.size()) {
+#ifndef NDEBUG
+  for (auto *E : SubExprs)
+    assert(E != nullptr);
+#endif
+
+  llvm::copy(SubExprs, getTrailingObjects<Expr *>());
+  setDependence(computeDependence(this));
+}
+
+RecoveryExpr *RecoveryExpr::Create(ASTContext &Ctx, SourceLocation BeginLoc,
+                                   SourceLocation EndLoc,
+                                   ArrayRef<Expr *> SubExprs) {
+  void *Mem = Ctx.Allocate(totalSizeToAlloc<Expr *>(SubExprs.size()),
+                           alignof(RecoveryExpr));
+  return new (Mem) RecoveryExpr(Ctx, BeginLoc, EndLoc, SubExprs);
+}
+
+RecoveryExpr *RecoveryExpr::CreateEmpty(ASTContext &Ctx, unsigned NumSubExprs) {
+  void *Mem = Ctx.Allocate(totalSizeToAlloc<Expr *>(NumSubExprs),
+                           alignof(RecoveryExpr));
+  return new (Mem) RecoveryExpr(EmptyShell());
+}

diff --git a/clang/lib/AST/ExprClassification.cpp b/clang/lib/AST/ExprClassification.cpp
index d201af3..58e7034 100644 (file)
--- a/clang/lib/AST/ExprClassification.cpp
+++ b/clang/lib/AST/ExprClassification.cpp
@@ -129,6 +129,7 @@ static Cl::Kinds ClassifyInternal(ASTContext &Ctx, const Expr *E) {
   case Expr::UnresolvedLookupExprClass:
   case Expr::UnresolvedMemberExprClass:
   case Expr::TypoExprClass:
+  case Expr::RecoveryExprClass:
   case Expr::DependentCoawaitExprClass:
   case Expr::CXXDependentScopeMemberExprClass:
   case Expr::DependentScopeDeclRefExprClass:

diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index ef56dbf..06f4885 100644 (file)
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -14189,6 +14189,7 @@ static ICEDiag CheckICE(const Expr* E, const ASTContext &Ctx) {
   case Expr::CXXPseudoDestructorExprClass:
   case Expr::UnresolvedLookupExprClass:
   case Expr::TypoExprClass:
+  case Expr::RecoveryExprClass:
   case Expr::DependentScopeDeclRefExprClass:
   case Expr::CXXConstructExprClass:
   case Expr::CXXInheritedCtorInitExprClass:

diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
index 12e1fc5..da723ed 100644 (file)
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -3672,7 +3672,8 @@ recurse:
   case Expr::LambdaExprClass:
   case Expr::MSPropertyRefExprClass:
   case Expr::MSPropertySubscriptExprClass:
-  case Expr::TypoExprClass:  // This should no longer exist in the AST by now.
+  case Expr::TypoExprClass: // This should no longer exist in the AST by now.
+  case Expr::RecoveryExprClass:
   case Expr::OMPArraySectionExprClass:
   case Expr::CXXInheritedCtorInitExprClass:
     llvm_unreachable("unexpected statement kind");

diff --git a/clang/lib/AST/StmtPrinter.cpp b/clang/lib/AST/StmtPrinter.cpp
index 68d0b14..80fdc09 100644 (file)
--- a/clang/lib/AST/StmtPrinter.cpp
+++ b/clang/lib/AST/StmtPrinter.cpp
@@ -2506,6 +2506,17 @@ void StmtPrinter::VisitTypoExpr(TypoExpr *Node) {
   llvm_unreachable("Cannot print TypoExpr nodes");
 }
 
+void StmtPrinter::VisitRecoveryExpr(RecoveryExpr *Node) {
+  OS << "<recovery-expr>(";
+  const char *Sep = "";
+  for (Expr *E : Node->subExpressions()) {
+    OS << Sep;
+    PrintExpr(E);
+    Sep = ", ";
+  }
+  OS << ')';
+}
+
 void StmtPrinter::VisitAsTypeExpr(AsTypeExpr *Node) {
   OS << "__builtin_astype(";
   PrintExpr(Node->getSrcExpr());

diff --git a/clang/lib/AST/StmtProfile.cpp b/clang/lib/AST/StmtProfile.cpp
index cd39024..5e87eb3 100644 (file)
--- a/clang/lib/AST/StmtProfile.cpp
+++ b/clang/lib/AST/StmtProfile.cpp
@@ -2025,6 +2025,8 @@ void StmtProfiler::VisitSourceLocExpr(const SourceLocExpr *E) {
   VisitExpr(E);
 }
 
+void StmtProfiler::VisitRecoveryExpr(const RecoveryExpr *E) { VisitExpr(E); }
+
 void StmtProfiler::VisitObjCStringLiteral(const ObjCStringLiteral *S) {
   VisitExpr(S);
 }

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 802df03..dc5e932 100644 (file)
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -2908,6 +2908,8 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
       !Args.hasArg(OPT_fno_concept_satisfaction_caching);
   if (Args.hasArg(OPT_fconcepts_ts))
     Diags.Report(diag::warn_fe_concepts_ts_flag);
+  Opts.RecoveryAST =
+      Args.hasFlag(OPT_frecovery_ast, OPT_fno_recovery_ast, false);
   Opts.HeinousExtensions = Args.hasArg(OPT_fheinous_gnu_extensions);
   Opts.AccessControl = !Args.hasArg(OPT_fno_access_control);
   Opts.ElideConstructors = !Args.hasArg(OPT_fno_elide_constructors);

diff --git a/clang/lib/Parse/ParseExpr.cpp b/clang/lib/Parse/ParseExpr.cpp
index 7bd1230..096e295 100644 (file)
--- a/clang/lib/Parse/ParseExpr.cpp
+++ b/clang/lib/Parse/ParseExpr.cpp
@@ -625,13 +625,31 @@ Parser::ParseRHSOfBinaryExpression(ExprResult LHS, prec::Level MinPrec) {
                          SourceRange(Actions.getExprRange(LHS.get()).getBegin(),
                                      Actions.getExprRange(RHS.get()).getEnd()));
 
-        LHS = Actions.ActOnBinOp(getCurScope(), OpToken.getLocation(),
-                                 OpToken.getKind(), LHS.get(), RHS.get());
-
+        ExprResult BinOp =
+            Actions.ActOnBinOp(getCurScope(), OpToken.getLocation(),
+                               OpToken.getKind(), LHS.get(), RHS.get());
+        if (BinOp.isInvalid())
+          BinOp = Actions.CreateRecoveryExpr(LHS.get()->getBeginLoc(),
+                                             RHS.get()->getEndLoc(),
+                                             {LHS.get(), RHS.get()});
+
+        LHS = BinOp;
       } else {
-        LHS = Actions.ActOnConditionalOp(OpToken.getLocation(), ColonLoc,
-                                         LHS.get(), TernaryMiddle.get(),
-                                         RHS.get());
+        ExprResult CondOp = Actions.ActOnConditionalOp(
+            OpToken.getLocation(), ColonLoc, LHS.get(), TernaryMiddle.get(),
+            RHS.get());
+        if (CondOp.isInvalid()) {
+          std::vector<clang::Expr *> Args;
+          // TernaryMiddle can be null for the GNU conditional expr extension.
+          if (TernaryMiddle.get())
+            Args = {LHS.get(), TernaryMiddle.get(), RHS.get()};
+          else
+            Args = {LHS.get(), RHS.get()};
+          CondOp = Actions.CreateRecoveryExpr(LHS.get()->getBeginLoc(),
+                                              RHS.get()->getEndLoc(), Args);
+        }
+
+        LHS = CondOp;
       }
       // In this case, ActOnBinOp or ActOnConditionalOp performed the
       // CorrectDelayedTyposInExpr check.
@@ -1305,9 +1323,14 @@ ExprResult Parser::ParseCastExpression(CastParseKind ParseKind,
       UnconsumeToken(SavedTok);
       return ExprError();
     }
-    if (!Res.isInvalid())
+    if (!Res.isInvalid()) {
+      Expr *Arg = Res.get();
       Res = Actions.ActOnUnaryOp(getCurScope(), SavedTok.getLocation(),
-                                 SavedKind, Res.get());
+                                 SavedKind, Arg);
+      if (Res.isInvalid())
+        Res = Actions.CreateRecoveryExpr(SavedTok.getLocation(),
+                                         Arg->getEndLoc(), Arg);
+    }
     return Res;
   }
   case tok::amp: {         // unary-expression: '&' cast-expression
@@ -1317,8 +1340,13 @@ ExprResult Parser::ParseCastExpression(CastParseKind ParseKind,
     SourceLocation SavedLoc = ConsumeToken();
     PreferredType.enterUnary(Actions, Tok.getLocation(), tok::amp, SavedLoc);
     Res = ParseCastExpression(AnyCastExpr, true);
-    if (!Res.isInvalid())
-      Res = Actions.ActOnUnaryOp(getCurScope(), SavedLoc, SavedKind, Res.get());
+    if (!Res.isInvalid()) {
+      Expr *Arg = Res.get();
+      Res = Actions.ActOnUnaryOp(getCurScope(), SavedLoc, SavedKind, Arg);
+      if (Res.isInvalid())
+        Res = Actions.CreateRecoveryExpr(Tok.getLocation(), Arg->getEndLoc(),
+                                         Arg);
+    }
     return Res;
   }
 
@@ -1334,8 +1362,12 @@ ExprResult Parser::ParseCastExpression(CastParseKind ParseKind,
     SourceLocation SavedLoc = ConsumeToken();
     PreferredType.enterUnary(Actions, Tok.getLocation(), SavedKind, SavedLoc);
     Res = ParseCastExpression(AnyCastExpr);
-    if (!Res.isInvalid())
-      Res = Actions.ActOnUnaryOp(getCurScope(), SavedLoc, SavedKind, Res.get());
+    if (!Res.isInvalid()) {
+      Expr *Arg = Res.get();
+      Res = Actions.ActOnUnaryOp(getCurScope(), SavedLoc, SavedKind, Arg);
+      if (Res.isInvalid())
+        Res = Actions.CreateRecoveryExpr(SavedLoc, Arg->getEndLoc(), Arg);
+    }
     return Res;
   }
 
@@ -1941,12 +1973,18 @@ Parser::ParsePostfixExpressionSuffix(ExprResult LHS) {
           PT.consumeClose();
         LHS = ExprError();
       } else {
-        assert((ArgExprs.size() == 0 ||
-                ArgExprs.size()-1 == CommaLocs.size())&&
-               "Unexpected number of commas!");
-        LHS = Actions.ActOnCallExpr(getCurScope(), LHS.get(), Loc,
-                                    ArgExprs, Tok.getLocation(),
+        assert(
+            (ArgExprs.size() == 0 || ArgExprs.size() - 1 == CommaLocs.size()) &&
+            "Unexpected number of commas!");
+        Expr *Fn = LHS.get();
+        SourceLocation RParLoc = Tok.getLocation();
+        LHS = Actions.ActOnCallExpr(getCurScope(), Fn, Loc, ArgExprs, RParLoc,
                                     ExecConfig);
+        if (LHS.isInvalid()) {
+          ArgExprs.insert(ArgExprs.begin(), Fn);
+          LHS =
+              Actions.CreateRecoveryExpr(Fn->getBeginLoc(), RParLoc, ArgExprs);
+        }
         PT.consumeClose();
       }
 
@@ -2069,8 +2107,12 @@ Parser::ParsePostfixExpressionSuffix(ExprResult LHS) {
     case tok::plusplus:    // postfix-expression: postfix-expression '++'
     case tok::minusminus:  // postfix-expression: postfix-expression '--'
       if (!LHS.isInvalid()) {
+        Expr *Arg = LHS.get();
         LHS = Actions.ActOnPostfixUnaryOp(getCurScope(), Tok.getLocation(),
-                                          Tok.getKind(), LHS.get());
+                                          Tok.getKind(), Arg);
+        if (LHS.isInvalid())
+          LHS = Actions.CreateRecoveryExpr(Arg->getBeginLoc(),
+                                           Tok.getLocation(), Arg);
       }
       ConsumeToken();
       break;

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 225f720..13fae1e 100644 (file)
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -21,6 +21,7 @@
 #include "clang/AST/DeclObjC.h"
 #include "clang/AST/DeclTemplate.h"
 #include "clang/AST/EvaluatedExprVisitor.h"
+#include "clang/AST/Expr.h"
 #include "clang/AST/ExprCXX.h"
 #include "clang/AST/NonTrivialTypeVisitor.h"
 #include "clang/AST/StmtCXX.h"
@@ -11500,6 +11501,7 @@ QualType Sema::deduceVarTypeFromInitializer(VarDecl *VDecl,
 
 bool Sema::DeduceVariableDeclarationType(VarDecl *VDecl, bool DirectInit,
                                          Expr *Init) {
+  assert(!Init || !Init->containsErrors());
   QualType DeducedType = deduceVarTypeFromInitializer(
       VDecl, VDecl->getDeclName(), VDecl->getType(), VDecl->getTypeSourceInfo(),
       VDecl->getSourceRange(), DirectInit, Init);
@@ -11837,7 +11839,7 @@ void Sema::AddInitializerToDecl(Decl *RealDecl, Expr *Init, bool DirectInit) {
     // be deduced based on the chosen correction if the original init contains a
     // TypoExpr.
     ExprResult Res = CorrectDelayedTyposInExpr(Init, VDecl);
-    if (!Res.isUsable()) {
+    if (!Res.isUsable() || Res.get()->containsErrors()) {
       RealDecl->setInvalidDecl();
       return;
     }

diff --git a/clang/lib/Sema/SemaExceptionSpec.cpp b/clang/lib/Sema/SemaExceptionSpec.cpp
index 6eb5b71..53c62a1 100644 (file)
--- a/clang/lib/Sema/SemaExceptionSpec.cpp
+++ b/clang/lib/Sema/SemaExceptionSpec.cpp
@@ -1340,6 +1340,7 @@ CanThrowResult Sema::canThrow(const Stmt *S) {
   case Expr::CXXUnresolvedConstructExprClass:
   case Expr::DependentScopeDeclRefExprClass:
   case Expr::CXXFoldExprClass:
+  case Expr::RecoveryExprClass:
     return CT_Dependent;
 
   case Expr::AsTypeExprClass:

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index afffd96..335ccab 100644 (file)
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -18414,3 +18414,17 @@ bool Sema::IsDependentFunctionNameExpr(Expr *E) {
   assert(E->isTypeDependent());
   return isa<UnresolvedLookupExpr>(E);
 }
+
+ExprResult Sema::CreateRecoveryExpr(SourceLocation Begin, SourceLocation End,
+                                    ArrayRef<Expr *> SubExprs) {
+  // FIXME: enable it for C++, RecoveryExpr is type-dependent to suppress
+  // bogus diagnostics and this trick does not work in C.
+  // FIXME: use containsErrors() to suppress unwanted diags in C.
+  if (!Context.getLangOpts().RecoveryAST)
+    return ExprError();
+
+  if (isSFINAEContext())
+    return ExprError();
+
+  return RecoveryExpr::Create(Context, Begin, End, SubExprs);
+}

diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index 65c924a..867ca5f 100644 (file)
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -3504,6 +3504,11 @@ public:
                                      Sema::AtomicArgumentOrder::AST);
   }
 
+  ExprResult RebuildRecoveryExpr(SourceLocation BeginLoc, SourceLocation EndLoc,
+                                 ArrayRef<Expr *> SubExprs) {
+    return getSema().CreateRecoveryExpr(BeginLoc, EndLoc, SubExprs);
+  }
+
 private:
   TypeLoc TransformTypeInObjectScope(TypeLoc TL,
                                      QualType ObjectType,
@@ -9867,6 +9872,24 @@ TreeTransform<Derived>::TransformTypoExpr(TypoExpr *E) {
   return E;
 }
 
+template <typename Derived>
+ExprResult TreeTransform<Derived>::TransformRecoveryExpr(RecoveryExpr *E) {
+  llvm::SmallVector<Expr *, 8> Children;
+  bool Changed = false;
+  for (Expr *C : E->subExpressions()) {
+    ExprResult NewC = getDerived().TransformExpr(C);
+    if (NewC.isInvalid())
+      return ExprError();
+    Children.push_back(NewC.get());
+
+    Changed |= NewC.get() != C;
+  }
+  if (!getDerived().AlwaysRebuild() && !Changed)
+    return E;
+  return getDerived().RebuildRecoveryExpr(E->getBeginLoc(), E->getEndLoc(),
+                                          Children);
+}
+
 template<typename Derived>
 ExprResult
 TreeTransform<Derived>::TransformPseudoObjectExpr(PseudoObjectExpr *E) {

diff --git a/clang/lib/Serialization/ASTReaderStmt.cpp b/clang/lib/Serialization/ASTReaderStmt.cpp
index c0ed123..5d9033e 100644 (file)
--- a/clang/lib/Serialization/ASTReaderStmt.cpp
+++ b/clang/lib/Serialization/ASTReaderStmt.cpp
@@ -2080,6 +2080,19 @@ void ASTStmtReader::VisitTypoExpr(TypoExpr *E) {
   llvm_unreachable("Cannot read TypoExpr nodes");
 }
 
+void ASTStmtReader::VisitRecoveryExpr(RecoveryExpr *E) {
+  VisitExpr(E);
+  unsigned NumArgs = Record.readInt();
+  E->BeginLoc = readSourceLocation();
+  E->EndLoc = readSourceLocation();
+  assert(
+      (NumArgs == std::distance(E->children().begin(), E->children().end())) &&
+      "Wrong NumArgs!");
+  (void)NumArgs;
+  for (Stmt *&Child : E->children())
+    Child = Record.readSubStmt();
+}
+
 //===----------------------------------------------------------------------===//
 // Microsoft Expressions and Statements
 //===----------------------------------------------------------------------===//
@@ -2857,6 +2870,11 @@ Stmt *ASTReader::ReadStmtFromStream(ModuleFile &F) {
           Context, /*NumArgs=*/Record[ASTStmtReader::NumExprFields], Empty);
       break;
 
+    case EXPR_RECOVERY:
+      S = RecoveryExpr::CreateEmpty(
+          Context, /*NumArgs=*/Record[ASTStmtReader::NumExprFields]);
+      break;
+
     case EXPR_MEMBER:
       S = MemberExpr::CreateEmpty(Context, Record[ASTStmtReader::NumExprFields],
                                   Record[ASTStmtReader::NumExprFields + 1],

diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index 0fc90f5..ddda393 100644 (file)
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -2280,7 +2280,7 @@ void ASTWriter::WriteDeclAbbrevs() {
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
-  Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ContainsErrors
+  Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ContainsErrors
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
   //DeclRefExpr
@@ -2304,7 +2304,7 @@ void ASTWriter::WriteDeclAbbrevs() {
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
-  Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ContainsErrors
+  Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ContainsErrors
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
   //Integer Literal
@@ -2323,7 +2323,7 @@ void ASTWriter::WriteDeclAbbrevs() {
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
-  Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ContainsErrors
+  Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ContainsErrors
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
   //Character Literal
@@ -2342,7 +2342,7 @@ void ASTWriter::WriteDeclAbbrevs() {
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ValueDependent
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //InstantiationDependent
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //UnexpandedParamPack
-  Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // ContainsErrors
+  Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); //ContainsErrors
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetValueKind
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3)); //GetObjectKind
   // CastExpr

diff --git a/clang/lib/Serialization/ASTWriterStmt.cpp b/clang/lib/Serialization/ASTWriterStmt.cpp
index 41f8bb8..d64e233 100644 (file)
--- a/clang/lib/Serialization/ASTWriterStmt.cpp
+++ b/clang/lib/Serialization/ASTWriterStmt.cpp
@@ -786,6 +786,16 @@ void ASTStmtWriter::VisitCallExpr(CallExpr *E) {
   Code = serialization::EXPR_CALL;
 }
 
+void ASTStmtWriter::VisitRecoveryExpr(RecoveryExpr *E) {
+  VisitExpr(E);
+  Record.push_back(std::distance(E->children().begin(), E->children().end()));
+  Record.AddSourceLocation(E->getBeginLoc());
+  Record.AddSourceLocation(E->getEndLoc());
+  for (Stmt *Child : E->children())
+    Record.AddStmt(Child);
+  Code = serialization::EXPR_RECOVERY;
+}
+
 void ASTStmtWriter::VisitMemberExpr(MemberExpr *E) {
   VisitExpr(E);
 

diff --git a/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp b/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
index 1bdf7f1..b9adee8 100644 (file)
--- a/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
+++ b/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
@@ -1225,6 +1225,7 @@ void ExprEngine::Visit(const Stmt *S, ExplodedNode *Pred,
     case Stmt::UnresolvedLookupExprClass:
     case Stmt::UnresolvedMemberExprClass:
     case Stmt::TypoExprClass:
+    case Stmt::RecoveryExprClass:
     case Stmt::CXXNoexceptExprClass:
     case Stmt::PackExpansionExprClass:
     case Stmt::SubstNonTypeTemplateParmPackExprClass:

diff --git a/clang/test/AST/ast-dump-expr-errors.cpp b/clang/test/AST/ast-dump-expr-errors.cpp
new file mode 100644 (file)
index 0000000..e623fad
--- /dev/null
+++ b/clang/test/AST/ast-dump-expr-errors.cpp
@@ -0,0 +1,46 @@
+// RUN: not %clang_cc1 -triple x86_64-unknown-unknown -Wno-unused-value -fcxx-exceptions -std=gnu++17 -ast-dump -frecovery-ast %s | FileCheck -strict-whitespace %s
+
+// Check errors flag is set for RecoveryExpr.
+//
+// CHECK:     VarDecl {{.*}} a
+// CHECK-NEXT:`-RecoveryExpr {{.*}} contains-errors
+// CHECK-NEXT:  `-UnresolvedLookupExpr {{.*}} 'bar'
+int a = bar();
+
+// The flag propagates through more complicated calls.
+//
+// CHECK:     VarDecl {{.*}} b
+// CHECK-NEXT:`-CallExpr {{.*}} contains-errors
+// CHECK-NEXT:  |-UnresolvedLookupExpr {{.*}} 'bar'
+// CHECK-NEXT:  |-RecoveryExpr {{.*}} contains-errors
+// CHECK-NEXT:  | `-UnresolvedLookupExpr {{.*}} 'baz'
+// CHECK-NEXT:   `-RecoveryExpr {{.*}} contains-errors
+// CHECK-NEXT:     `-UnresolvedLookupExpr {{.*}} 'qux'
+int b = bar(baz(), qux());
+
+// Also propagates through more complicated expressions.
+//
+// CHECK:     |-VarDecl {{.*}} c
+// CHECK-NEXT:| `-BinaryOperator {{.*}} '<dependent type>' contains-errors '*'
+// CHECK-NEXT:|   |-UnaryOperator {{.*}} '<dependent type>' contains-errors prefix '&'
+// CHECK-NEXT:|   | `-ParenExpr {{.*}} '<dependent type>' contains-errors
+// CHECK-NEXT:|   |   `-BinaryOperator {{.*}} '<dependent type>' contains-errors '+'
+// CHECK-NEXT:|   |     |-RecoveryExpr {{.*}} '<dependent type>' contains-errors
+// CHECK-NEXT:|   |     | `-UnresolvedLookupExpr {{.*}} 'bar'
+// CHECK-NEXT:|   |     `-RecoveryExpr {{.*}} '<dependent type>' contains-errors
+// CHECK-NEXT:|   |       `-UnresolvedLookupExpr {{.*}} 'baz'
+int c = &(bar() + baz()) * 10;
+
+// Errors flag propagates even when type is not dependent anymore.
+// CHECK:     |-VarDecl {{.*}} d
+// CHECK-NEXT:| `-CXXStaticCastExpr {{.*}} 'int' contains-errors
+// CHECK-NEXT:|   `-BinaryOperator {{.*}} '<dependent type>' contains-errors '+'
+// CHECK-NEXT:|     |-RecoveryExpr {{.*}} '<dependent type>' contains-errors
+// CHECK-NEXT:|     | `-UnresolvedLookupExpr {{.*}} 'bar'
+// CHECK-NEXT:|     `-IntegerLiteral {{.*}} 1
+int d = static_cast<int>(bar() + 1);
+
+// FIXME: store initializer even when 'auto' could not be deduced.
+// Expressions with errors currently do not keep initializers around.
+// CHECK:     `-VarDecl {{.*}} invalid e 'auto'
+auto e = bar();

diff --git a/clang/test/AST/ast-dump-recovery.cpp b/clang/test/AST/ast-dump-recovery.cpp
new file mode 100644 (file)
index 0000000..beb409e
--- /dev/null
+++ b/clang/test/AST/ast-dump-recovery.cpp
@@ -0,0 +1,85 @@
+// RUN: not %clang_cc1 -triple x86_64-unknown-unknown -Wno-unused-value -fcxx-exceptions -std=gnu++17 -frecovery-ast -ast-dump %s | FileCheck -strict-whitespace %s
+// RUN: not %clang_cc1 -triple x86_64-unknown-unknown -Wno-unused-value -fcxx-exceptions -std=gnu++17 -fno-recovery-ast -ast-dump %s | FileCheck --check-prefix=DISABLED -strict-whitespace %s
+
+int some_func(int *);
+
+// CHECK:     VarDecl {{.*}} invalid_call
+// CHECK-NEXT:`-RecoveryExpr {{.*}} contains-errors
+// CHECK-NEXT:  |-UnresolvedLookupExpr {{.*}} 'some_func'
+// CHECK-NEXT:  `-IntegerLiteral {{.*}} 123
+// DISABLED-NOT: -RecoveryExpr {{.*}} contains-errors
+int invalid_call = some_func(123);
+
+int ambig_func(double);
+int ambig_func(float);
+
+// CHECK:     VarDecl {{.*}} ambig_call
+// CHECK-NEXT:`-RecoveryExpr {{.*}} contains-errors
+// CHECK-NEXT:  |-UnresolvedLookupExpr {{.*}} 'ambig_func'
+// CHECK-NEXT:  `-IntegerLiteral {{.*}} 123
+// DISABLED-NOT: -RecoveryExpr {{.*}} contains-errors
+int ambig_call = ambig_func(123);
+
+// CHECK:     VarDecl {{.*}} unresolved_call1
+// CHECK-NEXT:`-RecoveryExpr {{.*}} contains-errors
+// CHECK-NEXT:  `-UnresolvedLookupExpr {{.*}} 'bar'
+// DISABLED-NOT: -RecoveryExpr {{.*}} contains-errors
+int unresolved_call1 = bar();
+
+// CHECK:     VarDecl {{.*}} unresolved_call2
+// CHECK-NEXT:`-CallExpr {{.*}} contains-errors
+// CHECK-NEXT:  |-UnresolvedLookupExpr {{.*}} 'bar'
+// CHECK-NEXT:  |-RecoveryExpr {{.*}} contains-errors
+// CHECK-NEXT:  | `-UnresolvedLookupExpr {{.*}} 'baz'
+// CHECK-NEXT:   `-RecoveryExpr {{.*}} contains-errors
+// CHECK-NEXT:     `-UnresolvedLookupExpr {{.*}} 'qux'
+// DISABLED-NOT: -RecoveryExpr {{.*}} contains-errors
+int unresolved_call2 = bar(baz(), qux());
+
+constexpr int a = 10;
+
+// CHECK:     VarDecl {{.*}} postfix_inc
+// CHECK-NEXT:`-RecoveryExpr {{.*}} contains-errors
+// CHECK-NEXT:  `-DeclRefExpr {{.*}} 'a'
+// DISABLED-NOT: -RecoveryExpr {{.*}} contains-errors
+int postfix_inc = a++;
+
+// CHECK:     VarDecl {{.*}} prefix_inc
+// CHECK-NEXT:`-RecoveryExpr {{.*}} contains-errors
+// CHECK-NEXT:  `-DeclRefExpr {{.*}} 'a'
+// DISABLED-NOT: -RecoveryExpr {{.*}} contains-errors
+int prefix_inc = ++a;
+
+// CHECK:     VarDecl {{.*}} unary_address
+// CHECK-NEXT:`-RecoveryExpr {{.*}} contains-errors
+// CHECK-NEXT:  `-ParenExpr {{.*}}
+// CHECK-NEXT:    `-BinaryOperator {{.*}} '+'
+// CHECK-NEXT:      |-ImplicitCastExpr
+// CHECK-NEXT:      | `-DeclRefExpr {{.*}} 'a'
+// DISABLED-NOT: -RecoveryExpr {{.*}} contains-errors
+int unary_address = &(a + 1);
+
+// CHECK:     VarDecl {{.*}} unary_bitinverse
+// CHECK-NEXT:`-RecoveryExpr {{.*}} contains-errors
+// CHECK-NEXT:  `-ParenExpr {{.*}}
+// CHECK-NEXT:    `-BinaryOperator {{.*}} '+'
+// CHECK-NEXT:      |-ImplicitCastExpr
+// CHECK-NEXT:      | `-ImplicitCastExpr
+// CHECK-NEXT:      |   `-DeclRefExpr {{.*}} 'a'
+// DISABLED-NOT: -RecoveryExpr {{.*}} contains-errors
+int unary_bitinverse = ~(a + 0.0);
+
+// CHECK:     VarDecl {{.*}} binary
+// CHECK-NEXT:`-RecoveryExpr {{.*}} contains-errors
+// CHECK-NEXT:  |-DeclRefExpr {{.*}} 'a'
+// CHECK-NEXT:  `-CXXNullPtrLiteralExpr
+// DISABLED-NOT: -RecoveryExpr {{.*}} contains-errors
+int binary = a + nullptr;
+
+// CHECK:     VarDecl {{.*}} ternary
+// CHECK-NEXT:`-RecoveryExpr {{.*}} contains-errors
+// CHECK-NEXT:  |-DeclRefExpr {{.*}} 'a'
+// CHECK-NEXT:  |-CXXNullPtrLiteralExpr
+// CHECK-NEXT:  `-DeclRefExpr {{.*}} 'a'
+// DISABLED-NOT: -RecoveryExpr {{.*}} contains-errors
+int ternary = a ? nullptr : a;

diff --git a/clang/test/Index/getcursor-recovery.cpp b/clang/test/Index/getcursor-recovery.cpp
new file mode 100644 (file)
index 0000000..29966f2
--- /dev/null
+++ b/clang/test/Index/getcursor-recovery.cpp
@@ -0,0 +1,16 @@
+int foo(int, int);
+int foo(int, double);
+int x;
+
+void testTypedRecoveryExpr() {
+  // Inner foo() is a RecoveryExpr, outer foo() is an overloaded call.
+  foo(x, foo(x));
+}
+// RUN: c-index-test -cursor-at=%s:7:3 %s -Xclang -frecovery-ast | FileCheck -check-prefix=OUTER-FOO %s
+// OUTER-FOO: OverloadedDeclRef=foo[2:5, 1:5]
+// RUN: c-index-test -cursor-at=%s:7:7 %s -Xclang -frecovery-ast | FileCheck -check-prefix=OUTER-X %s
+// OUTER-X: DeclRefExpr=x:3:5
+// RUN: c-index-test -cursor-at=%s:7:10 %s -Xclang -frecovery-ast | FileCheck -check-prefix=INNER-FOO %s
+// INNER-FOO: OverloadedDeclRef=foo[2:5, 1:5]
+// RUN: c-index-test -cursor-at=%s:7:14 %s -Xclang -frecovery-ast | FileCheck -check-prefix=INNER-X %s
+// INNER-X: DeclRefExpr=x:3:5

diff --git a/clang/test/SemaTemplate/recovery-tree-transform.cpp b/clang/test/SemaTemplate/recovery-tree-transform.cpp
new file mode 100644 (file)
index 0000000..bf882db
--- /dev/null
+++ b/clang/test/SemaTemplate/recovery-tree-transform.cpp
@@ -0,0 +1,4 @@
+// RUN: %clang_cc1 -verify -frecovery-ast %s
+
+template<typename T> int *p = &void(T::error); // expected-error{{cannot take the address of an rvalue}} expected-error{{type 'int' cannot be used prior to '::'}}
+int *q = p<int>; // expected-note{{in instantiation of variable template specialization 'p<int>' requested here}}

diff --git a/clang/tools/libclang/CXCursor.cpp b/clang/tools/libclang/CXCursor.cpp
index 5e857de..147e3ea 100644 (file)
--- a/clang/tools/libclang/CXCursor.cpp
+++ b/clang/tools/libclang/CXCursor.cpp
@@ -292,6 +292,7 @@ CXCursor cxcursor::MakeCXCursor(const Stmt *S, const Decl *Parent,
   case Stmt::ObjCDictionaryLiteralClass:
   case Stmt::ObjCBoxedExprClass:
   case Stmt::ObjCSubscriptRefExprClass:
+  case Stmt::RecoveryExprClass:
     K = CXCursor_UnexposedExpr;
     break;