[coroutines] Make generic lambda coroutines work

Summary:
1. Coroutine cannot be constexpr (added a check in SemaLambda.cpp not to mark coroutine as constexpr)
2. TransformCoroutineBodyStmt should transform ResultDecl and ReturnStmt

Reviewers: rsmith, GorNishanov

Reviewed By: GorNishanov

Subscribers: EricWF, cfe-commits

Differential Revision: https://reviews.llvm.org/D33498

llvm-svn: 303764

2 files changed, 14 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaLambda.cpp b/clang/lib/Sema/SemaLambda.cpp
index 7a9a8ff911a..4b1d7fd3cf2 100644
--- a/clang/lib/Sema/SemaLambda.cpp
+++ b/clang/lib/Sema/SemaLambda.cpp
@@ -1591,6 +1591,7 @@ ExprResult Sema::BuildLambdaExpr(SourceLocation StartLoc, SourceLocation EndLoc,
   // its constexpr-ness, supressing diagnostics while doing so.
   if (getLangOpts().CPlusPlus1z && !CallOperator->isInvalidDecl() &&
       !CallOperator->isConstexpr() &&
+      !isa<CoroutineBodyStmt>(CallOperator->getBody()) &&
       !Class->getDeclContext()->isDependentContext()) {
     TentativeAnalysisScope DiagnosticScopeGuard(*this);
     CallOperator->setConstexpr(
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index f4a97f55789..a65584e3c91 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -6945,6 +6945,19 @@ TreeTransform<Derived>::TransformCoroutineBodyStmt(CoroutineBodyStmt *S) {
     if (DeallocRes.isInvalid())
       return StmtError();
     Builder.Deallocate = DeallocRes.get();
+
+    assert(S->getResultDecl() && "ResultDecl must already be built");
+    StmtResult ResultDecl = getDerived().TransformStmt(S->getResultDecl());
+    if (ResultDecl.isInvalid())
+      return StmtError();
+    Builder.ResultDecl = ResultDecl.get();
+
+    if (auto *ReturnStmt = S->getReturnStmt()) {
+      StmtResult Res = getDerived().TransformStmt(ReturnStmt);
+      if (Res.isInvalid())
+        return StmtError();
+      Builder.ReturnStmt = Res.get();
+    }
   }
 
   return getDerived().RebuildCoroutineBodyStmt(Builder);