Index: clang/lib/AST/Interp/ByteCodeEmitter.h
===================================================================
--- clang/lib/AST/Interp/ByteCodeEmitter.h
+++ clang/lib/AST/Interp/ByteCodeEmitter.h
@@ -68,11 +68,10 @@
   /// Callback for local registration.
   Local createLocal(Descriptor *D);
 
-  /// Parameter indices.
-  llvm::DenseMap<const ParmVarDecl *, unsigned> Params;
+  /// Parameter indices. <AstNode*, pair<Offset, IsPrimitive>>
+  llvm::DenseMap<const ParmVarDecl *, ParamOffset> Params;
   /// Lambda captures.
-  /// Map from Decl* to [Offset, IsReference] pair.
-  llvm::DenseMap<const ValueDecl *, std::pair<unsigned, bool>> LambdaCaptures;
+  llvm::DenseMap<const ValueDecl *, ParamOffset> LambdaCaptures;
   unsigned LambdaThisCapture;
   /// Local descriptors.
   llvm::SmallVector<SmallVector<Local, 8>, 2> Descriptors;
Index: clang/lib/AST/Interp/ByteCodeEmitter.cpp
===================================================================
--- clang/lib/AST/Interp/ByteCodeEmitter.cpp
+++ clang/lib/AST/Interp/ByteCodeEmitter.cpp
@@ -74,13 +74,14 @@
   // Assign descriptors to all parameters.
   // Composite objects are lowered to pointers.
   for (const ParmVarDecl *PD : FuncDecl->parameters()) {
-    PrimType Ty = Ctx.classify(PD->getType()).value_or(PT_Ptr);
-    Descriptor *Desc = P.createDescriptor(PD, Ty);
-    ParamDescriptors.insert({ParamOffset, {Ty, Desc}});
-    Params.insert({PD, ParamOffset});
+    std::optional<PrimType> T = Ctx.classify(PD->getType());
+    PrimType PT = T.value_or(PT_Ptr);
+    Descriptor *Desc = P.createDescriptor(PD, PT);
+    ParamDescriptors.insert({ParamOffset, {PT, Desc}});
+    Params.insert({PD, {ParamOffset, T != std::nullopt}});
     ParamOffsets.push_back(ParamOffset);
-    ParamOffset += align(primSize(Ty));
-    ParamTypes.push_back(Ty);
+    ParamOffset += align(primSize(PT));
+    ParamTypes.push_back(PT);
   }
 
   // Create a handle over the emitted code.
Index: clang/lib/AST/Interp/ByteCodeExprGen.cpp
===================================================================
--- clang/lib/AST/Interp/ByteCodeExprGen.cpp
+++ clang/lib/AST/Interp/ByteCodeExprGen.cpp
@@ -1273,7 +1273,7 @@
     llvm::function_ref<bool(PrimType)> Indirect) {
   auto It = this->Params.find(PD);
   if (It != this->Params.end()) {
-    unsigned Idx = It->second;
+    unsigned Idx = It->second.Offset;
     switch (AK) {
     case DerefKind::Read:
       return DiscardResult ? true : this->emitGetParam(T, Idx, LV);
@@ -2253,18 +2253,19 @@
     return this->emitGetPtrGlobal(*GlobalIndex, E);
   } else if (const auto *PVD = dyn_cast<ParmVarDecl>(D)) {
     if (auto It = this->Params.find(PVD); It != this->Params.end()) {
-      if (IsReference)
-        return this->emitGetParamPtr(It->second, E);
-      return this->emitGetPtrParam(It->second, E);
+      if (IsReference || !It->second.IsPtr)
+        return this->emitGetParamPtr(It->second.Offset, E);
+
+      return this->emitGetPtrParam(It->second.Offset, E);
     }
   }
 
   // Handle lambda captures.
   if (auto It = this->LambdaCaptures.find(D);
       It != this->LambdaCaptures.end()) {
-    auto [Offset, IsReference] = It->second;
+    auto [Offset, IsPtr] = It->second;
 
-    if (IsReference)
+    if (IsPtr)
       return this->emitGetThisFieldPtr(Offset, E);
     return this->emitGetPtrThisField(Offset, E);
   }
Index: clang/lib/AST/Interp/ByteCodeStmtGen.cpp
===================================================================
--- clang/lib/AST/Interp/ByteCodeStmtGen.cpp
+++ clang/lib/AST/Interp/ByteCodeStmtGen.cpp
@@ -125,7 +125,7 @@
     // We do the lvalue-to-rvalue conversion manually here, so no need
     // to care about references.
     PrimType ParamType = this->classify(PVD->getType()).value_or(PT_Ptr);
-    if (!this->emitGetParam(ParamType, It->second, MD))
+    if (!this->emitGetParam(ParamType, It->second.Offset, MD))
       return false;
   }
 
Index: clang/lib/AST/Interp/Context.h
===================================================================
--- clang/lib/AST/Interp/Context.h
+++ clang/lib/AST/Interp/Context.h
@@ -31,6 +31,11 @@
 class State;
 enum PrimType : unsigned;
 
+struct ParamOffset {
+  unsigned Offset;
+  bool IsPtr;
+};
+
 /// Holds all information required to evaluate constexpr code in a module.
 class Context final {
 public:
Index: clang/lib/AST/Interp/Context.cpp
===================================================================
--- clang/lib/AST/Interp/Context.cpp
+++ clang/lib/AST/Interp/Context.cpp
@@ -27,6 +27,8 @@
 Context::~Context() {}
 
 bool Context::isPotentialConstantExpr(State &Parent, const FunctionDecl *FD) {
+  llvm::errs() << __PRETTY_FUNCTION__ << "\n";
+  FD->dump();
   assert(Stk.empty());
   Function *Func = P->getFunction(FD);
   if (!Func || !Func->hasBody()) {
@@ -51,6 +53,9 @@
 }
 
 bool Context::evaluateAsRValue(State &Parent, const Expr *E, APValue &Result) {
+  llvm::errs() << __PRETTY_FUNCTION__ << "\n";
+  E->dump();
+
   assert(Stk.empty());
   ByteCodeExprGen<EvalEmitter> C(*this, *P, Parent, Stk, Result);
   if (Check(Parent, C.interpretExpr(E))) {
Index: clang/lib/AST/Interp/EvalEmitter.h
===================================================================
--- clang/lib/AST/Interp/EvalEmitter.h
+++ clang/lib/AST/Interp/EvalEmitter.h
@@ -75,10 +75,9 @@
   }
 
   /// Parameter indices.
-  llvm::DenseMap<const ParmVarDecl *, unsigned> Params;
+  llvm::DenseMap<const ParmVarDecl *, ParamOffset> Params;
   /// Lambda captures.
-  /// Map from Decl* to [Offset, IsReference] pair.
-  llvm::DenseMap<const ValueDecl *, std::pair<unsigned, bool>> LambdaCaptures;
+  llvm::DenseMap<const ValueDecl *, ParamOffset> LambdaCaptures;
   unsigned LambdaThisCapture;
   /// Local descriptors.
   llvm::SmallVector<SmallVector<Local, 8>, 2> Descriptors;
Index: clang/test/AST/Interp/lambda.cpp
===================================================================
--- clang/test/AST/Interp/lambda.cpp
+++ clang/test/AST/Interp/lambda.cpp
@@ -103,10 +103,7 @@
 
     return a;
   }
-  /// FIXME: This should work in the new interpreter.
-#if 0
-  static_assert(foo() == 1); // expected-error {{not an integral constant expression}}
-#endif
+  static_assert(foo() == 1);
 }
 
 namespace LambdasAsParams {
Index: clang/test/AST/Interp/records.cpp
===================================================================
--- clang/test/AST/Interp/records.cpp
+++ clang/test/AST/Interp/records.cpp
@@ -896,9 +896,7 @@
 
 }
 
-#if 0
 constexpr bool BPand(BoolPair bp) {
   return bp.first && bp.second;
 }
 static_assert(BPand(BoolPair{true, false}) == false, "");
-#endif