[CodeGen] Fix a regression by emitting lambda expressions in EmitLValue

This ability was removed in r351487, but it's needed when a lambda appears as an
OpaqueValueExpr subexpression of a PseudoObjectExpr.

rdar://49030379

Differential revision: https://reviews.llvm.org/D60099

llvm-svn: 357515
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index f19af33..80a40df 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -1294,6 +1294,8 @@
     return EmitCXXBindTemporaryLValue(cast<CXXBindTemporaryExpr>(E));
   case Expr::CXXUuidofExprClass:
     return EmitCXXUuidofLValue(cast<CXXUuidofExpr>(E));
+  case Expr::LambdaExprClass:
+    return EmitAggExprToLValue(E);
 
   case Expr::ExprWithCleanupsClass: {
     const auto *cleanups = cast<ExprWithCleanups>(E);