Revert rL362358 : PR42104: Support instantiations of lambdas that implicitly capture packs.

Two changes:
 * Track odr-use via FunctionParmPackExprs to properly handle dependent
   odr-uses of packs in generic lambdas.
 * Do not instantiate implicit captures; instead, regenerate them by
   instantiating the body of the lambda. This is necessary to
   distinguish between cases where only one element of a pack is
   captured and cases where the entire pack is captured.
........
Fixes http://lab.llvm.org:8011/builders/llvm-clang-x86_64-expensive-checks-win buildbot failures

llvm-svn: 362375

1 files changed, 8 insertions, 3 deletions

diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 5884cf906fd..ac050fa1ef5 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -7427,7 +7427,12 @@ static void CheckIfAnyEnclosingLambdasMustCaptureAnyPotentialCaptures(
   // All the potentially captureable variables in the current nested
   // lambda (within a generic outer lambda), must be captured by an
   // outer lambda that is enclosed within a non-dependent context.
-  CurrentLSI->visitPotentialCaptures([&] (VarDecl *Var, Expr *VarExpr) {
+  const unsigned NumPotentialCaptures =
+      CurrentLSI->getNumPotentialVariableCaptures();
+  for (unsigned I = 0; I != NumPotentialCaptures; ++I) {
+    Expr *VarExpr = nullptr;
+    VarDecl *Var = nullptr;
+    CurrentLSI->getPotentialVariableCapture(I, Var, VarExpr);
     // If the variable is clearly identified as non-odr-used and the full
     // expression is not instantiation dependent, only then do we not
     // need to check enclosing lambda's for speculative captures.
@@ -7441,7 +7446,7 @@ static void CheckIfAnyEnclosingLambdasMustCaptureAnyPotentialCaptures(
     // }
     if (CurrentLSI->isVariableExprMarkedAsNonODRUsed(VarExpr) &&
         !IsFullExprInstantiationDependent)
-      return;
+      continue;
 
     // If we have a capture-capable lambda for the variable, go ahead and
     // capture the variable in that lambda (and all its enclosing lambdas).
@@ -7473,7 +7478,7 @@ static void CheckIfAnyEnclosingLambdasMustCaptureAnyPotentialCaptures(
                           DeclRefType, nullptr);
       }
     }
-  });
+  }
 
   // Check if 'this' needs to be captured.
   if (CurrentLSI->hasPotentialThisCapture()) {