// slang-ast-val.h

#pragma once

#include "slang-ast-base.h"

namespace Slang {

// Syntax class definitions for compile-time values.

class DirectDeclRef : public DeclRefBase
{
public:
    SLANG_AST_CLASS(DirectDeclRef)

    DirectDeclRef(Decl* decl)
    {
        setOperands(decl);
    }

    DeclRefBase* _substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet subst, int* ioDiff);
    void _toTextOverride(StringBuilder& out);
    Val* _resolveImplOverride();
    DeclRefBase* _getBaseOverride();
};

// Represent an static member of a base decl.
// Note that we automatically fold the DeclRef if the path is known to be static.
// For example, MemberDeclRef(DirectDeclRef(A), B) ==> DirectDeclRef(B),
// and MemberDeclRef(MemberDeclRef(A, B), C) ==> MemberDeclRef(A, C).
//
class MemberDeclRef : public DeclRefBase
{
public:
    SLANG_AST_CLASS(MemberDeclRef);

    DeclRefBase* getParentOperand() { return as<DeclRefBase>(getOperand(1)); }

    MemberDeclRef(Decl* decl, DeclRefBase* parent)
    {
        setOperands(decl, parent);
    }

    DeclRefBase* _substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet subst, int* ioDiff);

    void _toTextOverride(StringBuilder& out);

    Val* _resolveImplOverride();

    DeclRefBase* _getBaseOverride();
};


// Represent a lookup of SuperType::`m_decl` from `lookupSourceType` type that we know conforms to SuperType.
class LookupDeclRef : public DeclRefBase
{
public:
    SLANG_AST_CLASS(LookupDeclRef);

    // m_decl represents the decl in SuperType that we want to lookup.

    // The source type that we are looking up from.
    Type* getLookupSource()
    {
        return as<Type>(getOperand(1));
    }

    // Witness that `lookupSourceType`:SuperType.
    SubtypeWitness* getWitness()
    {
        return as<SubtypeWitness>(getOperand(2));
    }

    LookupDeclRef(Decl* declToLookup, Type* lookupSource, SubtypeWitness* witness)
    {
        setOperands(declToLookup, lookupSource, witness);
    }

    Decl* getSupDecl();

    DeclRefBase* _substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet subst, int* ioDiff);

    void _toTextOverride(StringBuilder& out);

    Val* _resolveImplOverride();

    DeclRefBase* _getBaseOverride();

private:
    Val* tryResolve(SubtypeWitness* newWitness, Type* newLookupSource);
};

// Represents a specialization of a generic decl.
class GenericAppDeclRef : public DeclRefBase
{
public:
    SLANG_AST_CLASS(GenericAppDeclRef);

    DeclRefBase* getGenericDeclRef() { return as<DeclRefBase>(getOperand(1)); }
    Index getArgCount() { return getOperandCount() - 2; }
    Val* getArg(Index index) { return getOperand(index + 2); }

    GenericAppDeclRef(Decl* innerDecl, DeclRefBase* genericDeclRef, OperandView<Val> args)
    {
        m_operands.add(ValNodeOperand(innerDecl));
        m_operands.add(ValNodeOperand(genericDeclRef));
        for (auto arg : args)
        {
            m_operands.add(ValNodeOperand(arg));
        }
    }

    GenericAppDeclRef(Decl* innerDecl, DeclRefBase* genericDeclRef, ConstArrayView<Val*> args)
    {
        m_operands.add(ValNodeOperand(innerDecl));
        m_operands.add(ValNodeOperand(genericDeclRef));
        for (auto arg : args)
        {
            m_operands.add(ValNodeOperand(arg));
        }
    }

    GenericDecl* getGenericDecl();

    OperandView<Val> getArgs() { return OperandView<Val>(this, 2, getArgCount()); }

    DeclRefBase* _substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet subst, int* ioDiff);

    void _toTextOverride(StringBuilder& out);

    Val* _resolveImplOverride();

    DeclRefBase* _getBaseOverride();
};

// A compile-time integer (may not have a specific concrete value)
class IntVal : public Val 
{
    SLANG_ABSTRACT_AST_CLASS(IntVal)

    Type* getType() { return as<Type>(getOperand(0)); }

    Val* _resolveImplOverride() { return this; }
};

// Trivial case of a value that is just a constant integer
class ConstantIntVal : public IntVal 
{
    SLANG_AST_CLASS(ConstantIntVal)

    IntegerLiteralValue getValue() { return getIntConstOperand(1); }

    // Overrides should be public so base classes can access
    void _toTextOverride(StringBuilder& out);

    ConstantIntVal(Type* inType, IntegerLiteralValue inValue)
    {
        setOperands(inType, inValue);
    }
};

// The logical "value" of a reference to a generic value parameter
class GenericParamIntVal : public IntVal 
{
    SLANG_AST_CLASS(GenericParamIntVal)

    DeclRef<VarDeclBase> getDeclRef() { return as<DeclRefBase>(getOperand(1)); }

    // Overrides should be public so base classes can access
    void _toTextOverride(StringBuilder& out);
    Val* _substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet subst, int* ioDiff);

    GenericParamIntVal(Type* inType, DeclRef<VarDeclBase> inDeclRef)
    {
        setOperands(inType, inDeclRef);
    }
};

class TypeCastIntVal : public IntVal
{
    SLANG_AST_CLASS(TypeCastIntVal)

    void _toTextOverride(StringBuilder& out);
    Val* _substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet subst, int* ioDiff);
    Val* _resolveImplOverride();

    Val* getBase() { return getOperand(1); }
    TypeCastIntVal(Type* inType, Val* inBase)
    {
        setOperands(inType, inBase);
    }

    static Val* tryFoldImpl(ASTBuilder* astBuilder, Type* resultType, Val* base, DiagnosticSink* sink);
};

// An compile time int val as result of some general computation.
class FuncCallIntVal : public IntVal
{
    SLANG_AST_CLASS(FuncCallIntVal)

    void _toTextOverride(StringBuilder& out);
    Val* _substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet subst, int* ioDiff);
    Val* _resolveImplOverride();

    DeclRef<Decl> getFuncDeclRef() { return as<DeclRefBase>(getOperand(1)); }
    Type* getFuncType() { return as<Type>(getOperand(2)); }
    OperandView<IntVal> getArgs() { return OperandView<IntVal>(this, 3, getOperandCount() - 3); }
    Index getArgCount() { return getOperandCount() - 3; }

    FuncCallIntVal(Type* inType, DeclRef<Decl> inFuncDeclRef, Type* inFuncType, ArrayView<IntVal*> inArgs)
    {
        setOperands(inType, inFuncDeclRef, inFuncType);
        for (auto arg : inArgs)
            m_operands.add(ValNodeOperand(arg));
    }

    static Val* tryFoldImpl(ASTBuilder* astBuilder, Type* resultType, DeclRef<Decl> newFuncDecl, List<IntVal*>& newArgs, DiagnosticSink* sink);
};

class WitnessLookupIntVal : public IntVal
{
    SLANG_AST_CLASS(WitnessLookupIntVal)

    void _toTextOverride(StringBuilder& out);
    Val* _substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet subst, int* ioDiff);
    Val* _resolveImplOverride();

    SubtypeWitness* getWitness() { return as<SubtypeWitness>(getOperand(1)); }
    Decl* getKey() { return as<Decl>(getDeclOperand(2)); }

    WitnessLookupIntVal(Type* inType, SubtypeWitness* witness, Decl* key)
    {
        setOperands(inType, witness, key);
    }

    static Val* tryFoldOrNull(ASTBuilder* astBuilder, SubtypeWitness* witness, Decl* key);

    static Val* tryFold(ASTBuilder* astBuilder, SubtypeWitness* witness, Decl* key, Type* type);
};

// polynomial expression "2*a*b^3 + 1" will be represented as:
// { constantTerm:1, terms: [ { constFactor:2, paramFactors:[{"a", 1}, {"b", 3}] } ] }
class PolynomialIntValFactor : public Val
{
    SLANG_AST_CLASS(PolynomialIntValFactor)
public:
    IntVal* getParam() const { return as<IntVal>(getOperand(0)); }
    IntegerLiteralValue getPower() const { return getIntConstOperand(1); }

    PolynomialIntValFactor(IntVal* inParam, IntegerLiteralValue inPower)
    {
        setOperands(inParam, inPower);
    }

    Val* _resolveImplOverride();

    // for sorting only.
    bool operator<(const PolynomialIntValFactor& other) const
    {
        if (auto thisGenParam = as<GenericParamIntVal>(getParam()))
        {
            if (auto thatGenParam = as<GenericParamIntVal>(other.getParam()))
            {
                if (thisGenParam->equals(thatGenParam))
                    return getPower() < other.getPower();
                else
                    return thisGenParam->getDeclRef().getDecl() < thatGenParam->getDeclRef().getDecl();
            }
            else
            {
                return true;
            }
        }
        else
        {
            if (const auto thatGenParam = as<GenericParamIntVal>(other.getParam()))
            {
                return false;
            }
            return getParam() == other.getParam() ? getPower() < other.getPower() : getParam() < other.getParam();
        }
        
    }
    // for sorting only.
    bool operator==(const PolynomialIntValFactor& other) const
    {
        if (auto thisGenParam = as<GenericParamIntVal>(getParam()))
        {
            if (auto thatGenParam = as<GenericParamIntVal>(other.getParam()))
            {
                if (thisGenParam->equals(thatGenParam) && getPower() == other.getPower())
                    return true;
            }
            return false;
        }
        return getPower() == other.getPower() && getParam() == other.getParam();
    }
    bool equals(const PolynomialIntValFactor& other) const
    {
        return getPower() == other.getPower() && getParam()->equals(other.getParam());
    }

};
class PolynomialIntValTerm : public Val
{
    SLANG_AST_CLASS(PolynomialIntValTerm)
public:
    IntegerLiteralValue getConstFactor() const { return getIntConstOperand(0); }
    OperandView<PolynomialIntValFactor> getParamFactors() const { return OperandView<PolynomialIntValFactor>(this, 1, getOperandCount() - 1); }

    Val* _resolveImplOverride();

    PolynomialIntValTerm(IntegerLiteralValue inConstFactor, ArrayView<PolynomialIntValFactor*> inParamFactors)
    {
        setOperands(inConstFactor);
        addOperands(inParamFactors);
    }

    PolynomialIntValTerm(IntegerLiteralValue inConstFactor, OperandView<PolynomialIntValFactor> inParamFactors)
    {
        setOperands(inConstFactor);
        addOperands(inParamFactors);
    }

    bool canCombineWith(const PolynomialIntValTerm& other) const
    {
        auto paramFactors = getParamFactors();
        if (paramFactors.getCount() != other.getParamFactors().getCount())
            return false;
        for (Index i = 0; i < getParamFactors().getCount(); i++)
        {
            if (!paramFactors[i]->equals(*other.getParamFactors()[i]))
                return false;
        }
        return true;
    }
    bool operator<(const PolynomialIntValTerm& other) const
    {
        auto constFactor = getConstFactor();
        auto paramFactors = getParamFactors();

        if (constFactor < other.getConstFactor())
            return true;
        else if (constFactor == other.getConstFactor())
        {
            auto otherParamFactors = other.getParamFactors();
            for (Index i = 0; i < paramFactors.getCount(); i++)
            {
                if (i >= otherParamFactors.getCount())
                    return false;
                if (*(paramFactors[i]) < *(otherParamFactors[i]))
                    return true;
                if (*(paramFactors[i]) == *(otherParamFactors[i]))
                {
                }
                else
                {
                    return false;
                }
            }
        }
        return false;
    }
};

class PolynomialIntVal : public IntVal
{
    SLANG_AST_CLASS(PolynomialIntVal)
public:
    
    IntegerLiteralValue getConstantTerm() { return getIntConstOperand(1); };
    OperandView<PolynomialIntValTerm> getTerms() { return OperandView<PolynomialIntValTerm>(this, 2, getOperandCount() - 2); };

    bool isConstant() { return getOperandCount() == 1; }

    // Overrides should be public so base classes can access
    void _toTextOverride(StringBuilder& out);
    Val* _substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet subst, int* ioDiff);
    Val* _resolveImplOverride();

    static IntVal* neg(ASTBuilder* astBuilder, IntVal* base);
    static IntVal* add(ASTBuilder* astBuilder, IntVal* op0, IntVal* op1);
    static IntVal* sub(ASTBuilder* astBuilder, IntVal* op0, IntVal* op1);
    static IntVal* mul(ASTBuilder* astBuilder, IntVal* op0, IntVal* op1);
    PolynomialIntVal(Type* inType, IntegerLiteralValue inConstantTerm, ArrayView<PolynomialIntValTerm*> inTerms)
    {
        setOperands(inType, inConstantTerm);
        addOperands(inTerms);
    }
};

    /// An unknown integer value indicating an erroneous sub-expression
class ErrorIntVal : public IntVal 
{
    SLANG_AST_CLASS(ErrorIntVal)

    ErrorIntVal(Type* inType) { setOperands(inType); }

    // TODO: We should probably eventually just have an `ErrorVal` here
    // and have all `Val`s that represent ordinary values hold their
    // `Type` so that we can have an `ErrorVal` of any type.

    // Overrides should be public so base classes can access
    void _toTextOverride(StringBuilder& out);
    Val* _substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet subst, int* ioDiff);
    Val* _resolveImplOverride() { return this;  }
};

// A witness to the fact that some proposition is true, encoded
// at the level of the type system.
//
// Given a generic like:
//
//     void example<L>(L light)
//          where L : ILight
//     { ... }
//
// a call to `example()` needs two things for us to be sure
// it is valid:
//
// 1. We need a type `X` to use as the argument for the
//    parameter `L`. We might supply this explicitly, or
//    via inference.
//
// 2. We need a *proof* that whatever `X` we chose conforms
//    to the `ILight` interface.
//
// The easiest way to make such a proof is by construction,
// and a `Witness` represents such a constructive proof.
// Conceptually a proposition like `X : ILight` can be
// seen as a type, and witness prooving that proposition
// is a value of that type.
//
// We construct and store witnesses explicitly during
// semantic checking because they can help us with
// generating downstream code. By following the structure
// of a witness (the structure of a proof) we can, e.g.,
// navigate from the knowledge that `X : ILight` to
// the concrete declarations that provide the implementation
// of `ILight` for `X`.
// 
class Witness : public Val 
{
    SLANG_ABSTRACT_AST_CLASS(Witness)
};

// A witness that one type is a subtype of another
// (where by "subtype" we include both inheritance
// relationships and type-conforms-to-interface relationships)
//
// TODO: we may need to tease those apart.
class SubtypeWitness : public Witness 
{
    SLANG_ABSTRACT_AST_CLASS(SubtypeWitness)

    Val* _resolveImplOverride();

    Type* getSub() { return as<Type>(getOperand(0)); }
    Type* getSup() { return as<Type>(getOperand(1)); }

    ConversionCost _getOverloadResolutionCostOverride();
    ConversionCost getOverloadResolutionCost();
};

class TypeEqualityWitness : public SubtypeWitness 
{
    SLANG_AST_CLASS(TypeEqualityWitness)

    TypeEqualityWitness(Type* subType, Type* supType)
    {
        setOperands(subType, supType);
    }

    // Overrides should be public so base classes can access
    void _toTextOverride(StringBuilder& out);
    Val* _substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet subst, int* ioDiff);
};

// A witness that one type is a subtype of another
// because some in-scope declaration says so
class DeclaredSubtypeWitness : public SubtypeWitness 
{
    SLANG_AST_CLASS(DeclaredSubtypeWitness)

    DeclRef<Decl> getDeclRef()
    {
        return as<DeclRefBase>(getOperand(2));
    }

    // Overrides should be public so base classes can access
    void _toTextOverride(StringBuilder& out);
    Val* _substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet subst, int* ioDiff);
    Val* _resolveImplOverride();

    DeclaredSubtypeWitness(Type* inSub, Type* inSup, DeclRef<Decl> inDeclRef)
    {
        setOperands(inSub, inSup, inDeclRef);
    }

    ConversionCost _getOverloadResolutionCostOverride();
};

// A witness that `sub : sup` because `sub : mid` and `mid : sup`
class TransitiveSubtypeWitness : public SubtypeWitness 
{
    SLANG_AST_CLASS(TransitiveSubtypeWitness)

    // Witness that `sub : mid`
    SubtypeWitness* getSubToMid()
    {
        return as<SubtypeWitness>(getOperand(2));
    }

    // Witness that `mid : sup`
    SubtypeWitness* getMidToSup()
    {
        return as<SubtypeWitness>(getOperand(3));
    }

    // Overrides should be public so base classes can access
    void _toTextOverride(StringBuilder& out);
    Val* _substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet subst, int* ioDiff);

    TransitiveSubtypeWitness(Type* subType, Type* supType, SubtypeWitness* inSubToMid, SubtypeWitness* inMidToSup)
    {
        setOperands(subType, supType, inSubToMid, inMidToSup);
    }

    ConversionCost _getOverloadResolutionCostOverride();
};

// A witness that `sub : sup` because `sub` was wrapped into
// an existential of type `sup`.
class ExtractExistentialSubtypeWitness : public SubtypeWitness 
{
    SLANG_AST_CLASS(ExtractExistentialSubtypeWitness)

    // The declaration of the existential value that has been opened
    DeclRef<VarDeclBase> getDeclRef() { return as<DeclRefBase>(getOperand(2)); }

    ExtractExistentialSubtypeWitness(Type* inSub, Type* inSup, DeclRef<Decl> inDeclRef)
    {
        setOperands(inSub, inSup, inDeclRef);
    }

    // Overrides should be public so base classes can access
    void _toTextOverride(StringBuilder& out);
    Val* _substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet subst, int* ioDiff);
};

    /// A witness of the fact that a user provided "__Dynamic" type argument is a
    /// subtype to the existential type parameter.
class DynamicSubtypeWitness : public SubtypeWitness
{
    SLANG_AST_CLASS(DynamicSubtypeWitness)
    DynamicSubtypeWitness(Type* inSub, Type* inSup)
    {
        setOperands(inSub, inSup);
    }
};

    /// A witness that `T : L & R` because `T : L` and `T : R`
class ConjunctionSubtypeWitness : public SubtypeWitness
{
    SLANG_AST_CLASS(ConjunctionSubtypeWitness)

    // At the operational level, this class of witness is
    // an operation that takes two witness tables `leftWitness`
    // and `rightWitness`, and forms a pair/tuple of
    // `(leftWitness, rightWitness)`.
    static const int kComponentCount = 2;

    ConjunctionSubtypeWitness(Type* inSub, Type* inSup, SubtypeWitness* left, SubtypeWitness* right)
    {
        setOperands(inSub, inSup, left, right);
    }

    SubtypeWitness* getLeftWitness() const { return as<SubtypeWitness>(getOperand(2)); }
    SubtypeWitness* getRightWitness() const { return as<SubtypeWitness>(getOperand(3)); }

    Count getComponentCount() const { return 2; }
    SubtypeWitness* getComponentWitness(Index index) const
    {
        SLANG_ASSERT(index >= 0 && index < kComponentCount);
        return as<SubtypeWitness>(getOperand(2 + index));
    }

    void _toTextOverride(StringBuilder& out);
    Val* _substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet subst, int* ioDiff);

    ConversionCost _getOverloadResolutionCostOverride();
};

    /// A witness that `T <: L` or `T <: R` because `T <: L&R`
class ExtractFromConjunctionSubtypeWitness : public SubtypeWitness
{
    SLANG_AST_CLASS(ExtractFromConjunctionSubtypeWitness)

    // At the operational level, this class of witness is
    // an operation that takes a pair/tuple of witness tables
    // `(leftWtiness, rightWitness)` and extracts one of the
    // elements of it.

    /// Witness that `T < L & R`
    SubtypeWitness* getConjunctionWitness() { return as<SubtypeWitness>(getOperand(2)); };

    ExtractFromConjunctionSubtypeWitness(Type* inSub, Type* inSup, SubtypeWitness* witness, int index)
    {
        setOperands(inSub, inSup, witness, index);
    }

        /// The zero-based index of the super-type we care about in the conjunction
        ///
        /// If `conjunctionWitness` is `T < L & R` then this index should be zero if
        /// we want to represent `T < L` and one if we want `T < R`.
        ///
    int getIndexInConjunction() { return (int)getIntConstOperand(3); };

    void _toTextOverride(StringBuilder& out);
    Val* _substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet subst, int* ioDiff);

    ConversionCost _getOverloadResolutionCostOverride();
};

    /// A value that represents a modifier attached to some other value
class ModifierVal : public Val
{
    SLANG_AST_CLASS(ModifierVal)

    Val* _resolveImplOverride() { return this; }
};

class TypeModifierVal : public ModifierVal
{
    SLANG_AST_CLASS(TypeModifierVal)
};

class ResourceFormatModifierVal : public TypeModifierVal
{
    SLANG_AST_CLASS(ResourceFormatModifierVal)
};

class UNormModifierVal : public ResourceFormatModifierVal
{
    SLANG_AST_CLASS(UNormModifierVal)

    void _toTextOverride(StringBuilder& out);
    Val* _substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet subst, int* ioDiff);
};

class SNormModifierVal : public ResourceFormatModifierVal
{
    SLANG_AST_CLASS(SNormModifierVal)

    void _toTextOverride(StringBuilder& out);
    Val* _substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet subst, int* ioDiff);
};

class NoDiffModifierVal : public TypeModifierVal
{
    SLANG_AST_CLASS(NoDiffModifierVal)

    void _toTextOverride(StringBuilder& out);
    Val* _substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet subst, int* ioDiff);
};

    /// Represents the result of differentiating a function.
class DifferentiateVal : public Val
{
    SLANG_AST_CLASS(DifferentiateVal)

    DifferentiateVal(DeclRef<Decl> inFunc)
    {
        setOperands(inFunc);
    }

    DeclRef<Decl> getFunc() { return as<DeclRefBase>(getOperand(0)); }

    void _toTextOverride(StringBuilder& out);
    Val* _substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet subst, int* ioDiff);
    Val* _resolveImplOverride();
};

class ForwardDifferentiateVal : public DifferentiateVal
{
    SLANG_AST_CLASS(ForwardDifferentiateVal)
    ForwardDifferentiateVal(DeclRef<Decl> inFunc)
        : DifferentiateVal(inFunc)
    {}
};

class BackwardDifferentiateVal : public DifferentiateVal
{
    SLANG_AST_CLASS(BackwardDifferentiateVal)

    BackwardDifferentiateVal(DeclRef<Decl> inFunc)
        : DifferentiateVal(inFunc)
    {}
};

class BackwardDifferentiateIntermediateTypeVal : public DifferentiateVal
{
    SLANG_AST_CLASS(BackwardDifferentiateIntermediateTypeVal)

    BackwardDifferentiateIntermediateTypeVal(DeclRef<Decl> inFunc)
        : DifferentiateVal(inFunc)
    {}
};

class BackwardDifferentiatePrimalVal : public DifferentiateVal
{
    SLANG_AST_CLASS(BackwardDifferentiatePrimalVal)

    BackwardDifferentiatePrimalVal(DeclRef<Decl> inFunc)
        : DifferentiateVal(inFunc)
    {}
};

class BackwardDifferentiatePropagateVal : public DifferentiateVal
{
    SLANG_AST_CLASS(BackwardDifferentiatePropagateVal)

    BackwardDifferentiatePropagateVal(DeclRef<Decl> inFunc)
        : DifferentiateVal(inFunc)
    {}
};


template<typename F>
void SubstitutionSet::forEachGenericSubstitution(F func) const
{
    if (!declRef)
        return;
    for (auto subst = declRef; subst; subst = subst->getBase())
    {
        if (auto genSubst = as<GenericAppDeclRef>(subst))
            func(genSubst->getGenericDecl(), genSubst->getArgs());
    }
}

template<typename F>
void SubstitutionSet::forEachSubstitutionArg(F func) const
{
    if (!declRef)
        return;
    for (auto subst = declRef; subst; subst = subst->getBase())
    {
        if (auto genSubst = as<GenericAppDeclRef>(subst))
        {
            for (auto arg : genSubst->getArgs())
                func(arg);
        }
        else if (auto thisSubst = as<LookupDeclRef>(subst))
        {
            func(thisSubst->getWitness()->getSub());
        }
    }
}
} // namespace Slang