[coroutines] Fix co_await for range statement

Summary:
Currently we build the co_await expressions on the wrong implicit statements of the implicit ranged for; Specifically we build the co_await expression wrapping the range declaration, but it should wrap the begin expression.

This patch fixes co_await on range for.

Reviewers: rsmith, GorNishanov

Reviewed By: GorNishanov

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D34021

llvm-svn: 305363

1 files changed, 32 insertions, 20 deletions

diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index 0c35f9a571d..eed10b077eb 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -1989,11 +1989,11 @@ StmtResult Sema::ActOnCXXForRangeStmt(Scope *S, SourceLocation ForLoc,
     return StmtError();
   }
 
-  // Coroutines: 'for co_await' implicitly co_awaits its range.
-  if (CoawaitLoc.isValid()) {
-    ExprResult Coawait = ActOnCoawaitExpr(S, CoawaitLoc, Range);
-    if (Coawait.isInvalid()) return StmtError();
-    Range = Coawait.get();
+  // Build the coroutine state immediately and not later during template
+  // instantiation
+  if (!CoawaitLoc.isInvalid()) {
+    if (!ActOnCoroutineBodyStart(S, CoawaitLoc, "co_await"))
+      return StmtError();
   }
 
   // Build  auto && __range = range-init
@@ -2031,16 +2031,12 @@ StmtResult Sema::ActOnCXXForRangeStmt(Scope *S, SourceLocation ForLoc,
 /// BeginExpr and EndExpr are set and FRS_Success is returned on success;
 /// CandidateSet and BEF are set and some non-success value is returned on
 /// failure.
-static Sema::ForRangeStatus BuildNonArrayForRange(Sema &SemaRef,
-                                            Expr *BeginRange, Expr *EndRange,
-                                            QualType RangeType,
-                                            VarDecl *BeginVar,
-                                            VarDecl *EndVar,
-                                            SourceLocation ColonLoc,
-                                            OverloadCandidateSet *CandidateSet,
-                                            ExprResult *BeginExpr,
-                                            ExprResult *EndExpr,
-                                            BeginEndFunction *BEF) {
+static Sema::ForRangeStatus
+BuildNonArrayForRange(Sema &SemaRef, Expr *BeginRange, Expr *EndRange,
+                      QualType RangeType, VarDecl *BeginVar, VarDecl *EndVar,
+                      SourceLocation ColonLoc, SourceLocation CoawaitLoc,
+                      OverloadCandidateSet *CandidateSet, ExprResult *BeginExpr,
+                      ExprResult *EndExpr, BeginEndFunction *BEF) {
   DeclarationNameInfo BeginNameInfo(
       &SemaRef.PP.getIdentifierTable().get("begin"), ColonLoc);
   DeclarationNameInfo EndNameInfo(&SemaRef.PP.getIdentifierTable().get("end"),
@@ -2087,6 +2083,15 @@ static Sema::ForRangeStatus BuildNonArrayForRange(Sema &SemaRef,
           << ColonLoc << BEF_begin << BeginRange->getType();
     return RangeStatus;
   }
+  if (!CoawaitLoc.isInvalid()) {
+    // FIXME: getCurScope() should not be used during template instantiation.
+    // We should pick up the set of unqualified lookup results for operator
+    // co_await during the initial parse.
+    *BeginExpr = SemaRef.ActOnCoawaitExpr(SemaRef.getCurScope(), ColonLoc,
+                                          BeginExpr->get());
+    if (BeginExpr->isInvalid())
+      return Sema::FRS_DiagnosticIssued;
+  }
   if (FinishForRangeVarDecl(SemaRef, BeginVar, BeginExpr->get(), ColonLoc,
                             diag::err_for_range_iter_deduction_failure)) {
     NoteForRangeBeginEndFunction(SemaRef, BeginExpr->get(), *BEF);
@@ -2253,6 +2258,11 @@ Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation CoawaitLoc,
 
       // begin-expr is __range.
       BeginExpr = BeginRangeRef;
+      if (!CoawaitLoc.isInvalid()) {
+        BeginExpr = ActOnCoawaitExpr(S, ColonLoc, BeginExpr.get());
+        if (BeginExpr.isInvalid())
+          return StmtError();
+      }
       if (FinishForRangeVarDecl(*this, BeginVar, BeginRangeRef.get(), ColonLoc,
                                 diag::err_for_range_iter_deduction_failure)) {
         NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
@@ -2335,11 +2345,10 @@ Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation CoawaitLoc,
       OverloadCandidateSet CandidateSet(RangeLoc,
                                         OverloadCandidateSet::CSK_Normal);
       BeginEndFunction BEFFailure;
-      ForRangeStatus RangeStatus =
-          BuildNonArrayForRange(*this, BeginRangeRef.get(),
-                                EndRangeRef.get(), RangeType,
-                                BeginVar, EndVar, ColonLoc, &CandidateSet,
-                                &BeginExpr, &EndExpr, &BEFFailure);
+      ForRangeStatus RangeStatus = BuildNonArrayForRange(
+          *this, BeginRangeRef.get(), EndRangeRef.get(), RangeType, BeginVar,
+          EndVar, ColonLoc, CoawaitLoc, &CandidateSet, &BeginExpr, &EndExpr,
+          &BEFFailure);
 
       if (Kind == BFRK_Build && RangeStatus == FRS_NoViableFunction &&
           BEFFailure == BEF_begin) {
@@ -2436,6 +2445,9 @@ Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation CoawaitLoc,
 
     IncrExpr = ActOnUnaryOp(S, ColonLoc, tok::plusplus, BeginRef.get());
     if (!IncrExpr.isInvalid() && CoawaitLoc.isValid())
+      // FIXME: getCurScope() should not be used during template instantiation.
+      // We should pick up the set of unqualified lookup results for operator
+      // co_await during the initial parse.
       IncrExpr = ActOnCoawaitExpr(S, CoawaitLoc, IncrExpr.get());
     if (!IncrExpr.isInvalid())
       IncrExpr = ActOnFinishFullExpr(IncrExpr.get());