[clang] [clang][Sema] Fix a bug when instantiating a lambda with requires clause (PR #65193)

[via cfe-commits]

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@@ -567,6 +567,58 @@ bool Sema::addInstantiatedCapturesToScope(
   return false;
 }
 
+static void addDeclsFromParentScope(Sema &S, FunctionDecl *FD,
+                                    LocalInstantiationScope &Scope) {
+  assert(isLambdaCallOperator(FD) && "FD must be a lambda call operator");
+
+  LambdaScopeInfo *LSI = cast<LambdaScopeInfo>(S.getFunctionScopes().back());
+
+  auto captureVar = [&](VarDecl *VD) {
+    LSI->addCapture(VD, /*isBlock=*/false, /*isByref=*/false,
+                    /*isNested=*/false, VD->getBeginLoc(), SourceLocation(),
+                    VD->getType(), /*Invalid=*/false);
+  };
+
+  FD = dyn_cast<FunctionDecl>(FD->getParent()->getParent());
+
+  if (!FD || !FD->isTemplateInstantiation())
+    return;
+
+  FunctionDecl *Pattern = FD->getPrimaryTemplate()->getTemplatedDecl();
+
+  for (unsigned I = 0; I < Pattern->getNumParams(); ++I) {
+    ParmVarDecl *PVD = Pattern->getParamDecl(I);
+    if (!PVD->isParameterPack()) {
+      Scope.InstantiatedLocal(PVD, FD->getParamDecl(I));
+      captureVar(FD->getParamDecl(I));
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cor3ntin wrote:

These are not captures, adding them to the instantiation scope should be enough

https://github.com/llvm/llvm-project/pull/65193