add defensive guards for eval/coeff forms

lib/Dialect/Polynomial/Conversions/PolynomialToModArith/PolynomialToModArith.cpp

@@ -219,6 +219,11 @@ struct ConvertFromTensor : public OpConversionPattern<FromTensorOp> {
     }
     auto typeInfo = res.value();
 
+    if (typeInfo.polynomialType.getForm() != Form::COEFF) {
+      return rewriter.notifyMatchFailure(
+          op, "FromTensor lowering requires COEFF form");
+    }
+
     auto resultShape = typeInfo.tensorType.getShape()[0];
     auto resultEltTy = typeInfo.tensorType.getElementType();
     auto inputTensorTy = op.getInput().getType();
@@ -276,6 +281,11 @@ struct ConvertConstant : public OpConversionPattern<ConstantOp> {
 
     auto typeInfo = res.value();
 
+    if (typeInfo.polynomialType.getForm() != Form::COEFF) {
+      return rewriter.notifyMatchFailure(
+          op, "Constant lowering requires COEFF form");
+    }
+
     auto attr = dyn_cast<TypedIntPolynomialAttr>(op.getValue());
     if (!attr)
       return rewriter.notifyMatchFailure(op,
@@ -362,6 +372,11 @@ struct ConvertMonomial : public OpConversionPattern<MonomialOp> {
           op, "failed to construct common conversion info");
     auto typeInfo = res.value();
 
+    if (typeInfo.polynomialType.getForm() != Form::COEFF) {
+      return rewriter.notifyMatchFailure(
+          op, "Monomial lowering requires COEFF form");
+    }
+
     SmallVector<int64_t> storageShape(typeInfo.tensorType.getShape().begin(),
                                       typeInfo.tensorType.getShape().end());
     if (auto rnsType = dyn_cast<RNSType>(typeInfo.coefficientType)) {
@@ -514,6 +529,11 @@ struct ConvertMonicMonomialMul
           op, "failed to construct common conversion info");
     auto typeInfo = res.value();
 
+    if (typeInfo.polynomialType.getForm() != Form::COEFF) {
+      return rewriter.notifyMatchFailure(
+          op, "MonicMonomialMul lowering requires COEFF form");
+    }
+
     ImplicitLocOpBuilder b(op.getLoc(), rewriter);
     // In general, a rotation would correspond to multiplication by x^n,
     // which requires a modular reduction step. But because the verifier
@@ -600,6 +620,11 @@ struct ConvertLeadingTerm : public OpConversionPattern<LeadingTermOp> {
           op, "failed to construct common conversion info");
     auto typeInfo = res.value();
 
+    if (typeInfo.polynomialType.getForm() != Form::COEFF) {
+      return rewriter.notifyMatchFailure(
+          op, "LeadingTerm lowering requires COEFF form");
+    }
+
     auto c0 = arith::ConstantOp::create(
         b, b.getIntegerAttr(typeInfo.coefficientStorageType, 0));
     auto c1 = arith::ConstantOp::create(b, b.getIndexAttr(1));
@@ -655,6 +680,11 @@ struct ConvertApplyCoefficientwise
           op, "failed to construct common conversion info");
     auto typeInfo = res.value();
 
+    if (typeInfo.polynomialType.getForm() != Form::COEFF) {
+      return rewriter.notifyMatchFailure(
+          op, "ApplyCoefficientwise lowering requires COEFF form");
+    }
+
     ImplicitLocOpBuilder b(op.getLoc(), rewriter);
     Value inputTensor = adaptor.getInput();
     // Implicitly we're relying on the fact that the operand has already been
@@ -1466,6 +1496,11 @@ struct ConvertNTT : public OpConversionPattern<NTTOp> {
           op, "missing convert-elementwise-to-affine");
     }
 
+    if (polyTy.getForm() != Form::COEFF) {
+      return rewriter.notifyMatchFailure(op,
+                                         "NTT lowering requires COEFF form");
+    }
+
     if (!op.getRoot()) {
       return rewriter.notifyMatchFailure(op, "missing root attribute");
     }
@@ -1517,6 +1552,11 @@ struct ConvertINTT : public OpConversionPattern<INTTOp> {
           op, "failed to construct common conversion info");
     auto typeInfo = res.value();
 
+    if (typeInfo.polynomialType.getForm() != Form::EVAL) {
+      return rewriter.notifyMatchFailure(op,
+                                         "INTT lowering requires EVAL form");
+    }
+
     if (!op.getRoot()) {
       op.emitError("missing root attribute");
       return rewriter.notifyMatchFailure(op, "missing root attribute");