// Copyright 2021 The Tint Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "src/tint/lang/core/intrinsic/table.h"

#include <algorithm>
#include <limits>
#include <utility>

#include "src/tint/lang/core/evaluation_stage.h"
#include "src/tint/lang/core/intrinsic/table_data.h"
#include "src/tint/lang/core/type/manager.h"
#include "src/tint/lang/core/type/void.h"
#include "src/tint/utils/containers/hashmap.h"
#include "src/tint/utils/diagnostic/diagnostic.h"
#include "src/tint/utils/macros/scoped_assignment.h"
#include "src/tint/utils/math/hash.h"
#include "src/tint/utils/math/math.h"
#include "src/tint/utils/rtti/switch.h"
#include "src/tint/utils/text/string_stream.h"

namespace tint::core::intrinsic {

const Number Number::any{Number::kAny};
const Number Number::invalid{Number::kInvalid};

Any::Any() : Base(0u, core::type::Flags{}) {}
Any::~Any() = default;

bool Any::Equals(const core::type::UniqueNode&) const {
    return false;
}

std::string Any::FriendlyName() const {
    return "<any>";
}

core::type::Type* Any::Clone(core::type::CloneContext&) const {
    return nullptr;
}

namespace {

/// The Vector `N` template argument value for arrays of parameters.
constexpr const size_t kNumFixedParams = decltype(Overload{}.parameters)::static_length;

/// The Vector `N` template argument value for arrays of overload candidates.
constexpr const size_t kNumFixedCandidates = 8;

/// Candidate holds information about an overload evaluated for resolution.
struct Candidate {
    /// The candidate overload
    const OverloadInfo* overload;
    /// The template types and numbers
    TemplateState templates;
    /// The parameter types for the candidate overload
    Vector<Overload::Parameter, kNumFixedParams> parameters;
    /// The match-score of the candidate overload.
    /// A score of zero indicates an exact match.
    /// Non-zero scores are used for diagnostics when no overload matches.
    /// Lower scores are displayed first (top-most).
    size_t score;
};

/// A list of candidates
using Candidates = Vector<Candidate, kNumFixedCandidates>;

/// Callback function when no overloads match.
using OnNoMatch = std::function<void(VectorRef<Candidate>)>;

/// Sorts the candidates based on their score, with the lowest (best-ranking) scores first.
static inline void SortCandidates(Candidates& candidates) {
    std::stable_sort(candidates.begin(), candidates.end(),
                     [&](const Candidate& a, const Candidate& b) { return a.score < b.score; });
}

/// Attempts to find a single intrinsic overload that matches the provided argument types.
/// @param context the intrinsic context
/// @param intrinsic the intrinsic being called
/// @param intrinsic_name the name of the intrinsic
/// @param args the argument types
/// @param templates initial template state. This may contain explicitly specified template
///                  arguments. For example `vec3<f32>()` would have the first template-type
///                  defined as `f32`.
/// @param on_no_match an error callback when no intrinsic overloads matched the provided
///                    arguments.
/// @returns the matched intrinsic
Result<Overload> MatchIntrinsic(Context& context,
                                const IntrinsicInfo& intrinsic,
                                const char* intrinsic_name,
                                VectorRef<const core::type::Type*> args,
                                EvaluationStage earliest_eval_stage,
                                TemplateState templates,
                                const OnNoMatch& on_no_match);

/// Evaluates the single overload for the provided argument types.
/// @param context the intrinsic context
/// @param overload the overload being considered
/// @param args the argument types
/// @param templates initial template state. This may contain explicitly specified template
///                  arguments. For example `vec3<f32>()` would have the first template-type
///                  template as `f32`.
/// @returns the evaluated Candidate information.
Candidate ScoreOverload(Context& context,
                        const OverloadInfo& overload,
                        VectorRef<const core::type::Type*> args,
                        EvaluationStage earliest_eval_stage,
                        const TemplateState& templates);

/// Performs overload resolution given the list of candidates, by ranking the conversions of
/// arguments to the each of the candidate's parameter types.
/// @param context the intrinsic context
/// @param candidates the list of candidate overloads
/// @param intrinsic_name the name of the intrinsic
/// @param args the argument types
/// @param templates initial template state. This may contain explicitly specified template
///                  arguments. For example `vec3<f32>()` would have the first template-type
///                  template as `f32`.
/// @see https://www.w3.org/TR/WGSL/#overload-resolution-section
/// @returns the resolved Candidate.
Candidate ResolveCandidate(Context& context,
                           Candidates&& candidates,
                           const char* intrinsic_name,
                           VectorRef<const core::type::Type*> args,
                           TemplateState templates);

/// Match constructs a new MatchState
/// @param context the intrinsic context
/// @param templates the template state used for matcher evaluation
/// @param overload the overload being evaluated
/// @param type_matcher_indices pointer to a list of type matcher indices
/// @param number_matcher_indices pointer to a list of number matcher indices
MatchState Match(Context& context,
                 TemplateState& templates,
                 const OverloadInfo& overload,
                 const TypeMatcherIndex* type_matcher_indices,
                 const NumberMatcherIndex* number_matcher_indices,
                 EvaluationStage earliest_eval_stage);

// Prints the overload for emitting diagnostics
void PrintOverload(StringStream& ss,
                   Context& context,
                   const OverloadInfo& overload,
                   const char* intrinsic_name);

// Prints the list of candidates for emitting diagnostics
void PrintCandidates(StringStream& ss,
                     Context& context,
                     VectorRef<Candidate> candidates,
                     const char* intrinsic_name);

/// Raises an error when no overload is a clear winner of overload resolution
void ErrAmbiguousOverload(Context& context,
                          const char* intrinsic_name,
                          VectorRef<const core::type::Type*> args,
                          TemplateState templates,
                          VectorRef<Candidate> candidates);

/// @return a string representing a call to a builtin with the given argument
/// types.
std::string CallSignature(const char* intrinsic_name,
                          VectorRef<const core::type::Type*> args,
                          const core::type::Type* template_arg = nullptr) {
    StringStream ss;
    ss << intrinsic_name;
    if (template_arg) {
        ss << "<" << template_arg->FriendlyName() << ">";
    }
    ss << "(";
    {
        bool first = true;
        for (auto* arg : args) {
            if (!first) {
                ss << ", ";
            }
            first = false;
            ss << arg->UnwrapRef()->FriendlyName();
        }
    }
    ss << ")";

    return ss.str();
}

Result<Overload> MatchIntrinsic(Context& context,
                                const IntrinsicInfo& intrinsic,
                                const char* intrinsic_name,
                                VectorRef<const core::type::Type*> args,
                                EvaluationStage earliest_eval_stage,
                                TemplateState templates,
                                const OnNoMatch& on_no_match) {
    size_t num_matched = 0;
    size_t match_idx = 0;
    Vector<Candidate, kNumFixedCandidates> candidates;
    candidates.Reserve(intrinsic.num_overloads);
    for (size_t overload_idx = 0; overload_idx < static_cast<size_t>(intrinsic.num_overloads);
         overload_idx++) {
        auto& overload = context.data[intrinsic.overloads + overload_idx];
        auto candidate = ScoreOverload(context, overload, args, earliest_eval_stage, templates);
        if (candidate.score == 0) {
            match_idx = overload_idx;
            num_matched++;
        }
        candidates.Push(std::move(candidate));
    }

    // How many candidates matched?
    if (num_matched == 0) {
        // Sort the candidates with the most promising first
        SortCandidates(candidates);
        on_no_match(std::move(candidates));
        return Failure{};
    }

    Candidate match;

    if (num_matched == 1) {
        match = std::move(candidates[match_idx]);
    } else {
        match = ResolveCandidate(context, std::move(candidates), intrinsic_name, args,
                                 std::move(templates));
        if (!match.overload) {
            // Ambiguous overload. ResolveCandidate() will have already raised an error diagnostic.
            return Failure{};
        }
    }

    // Build the return type
    const core::type::Type* return_type = nullptr;
    if (auto* type_indices = context.data[match.overload->return_type_matcher_indices]) {
        auto* number_indices = context.data[match.overload->return_number_matcher_indices];
        Any any;
        return_type = Match(context, match.templates, *match.overload, type_indices, number_indices,
                            earliest_eval_stage)
                          .Type(&any);
        if (TINT_UNLIKELY(!return_type)) {
            TINT_ICE() << "MatchState.Match() returned null";
            return Failure{};
        }
    } else {
        return_type = context.types.void_();
    }

    return Overload{match.overload, return_type, std::move(match.parameters),
                    context.data[match.overload->const_eval_fn]};
}

Candidate ScoreOverload(Context& context,
                        const OverloadInfo& overload,
                        VectorRef<const core::type::Type*> args,
                        EvaluationStage earliest_eval_stage,
                        const TemplateState& in_templates) {
    // Penalty weights for overload mismatching.
    // This scoring is used to order the suggested overloads in diagnostic on overload mismatch, and
    // has no impact for a correct program.
    // The overloads with the lowest score will be displayed first (top-most).
    constexpr int kMismatchedParamCountPenalty = 3;
    constexpr int kMismatchedParamTypePenalty = 2;
    constexpr int kMismatchedTemplateCountPenalty = 1;
    constexpr int kMismatchedTemplateTypePenalty = 1;
    constexpr int kMismatchedTemplateNumberPenalty = 1;

    size_t num_parameters = static_cast<size_t>(overload.num_parameters);
    size_t num_arguments = static_cast<size_t>(args.Length());

    size_t score = 0;

    if (num_parameters != num_arguments) {
        score += kMismatchedParamCountPenalty * (std::max(num_parameters, num_arguments) -
                                                 std::min(num_parameters, num_arguments));
    }

    if (score == 0) {
        // Check that all of the template arguments provided are actually expected by the overload.
        size_t expected_templates = overload.num_template_types + overload.num_template_numbers;
        size_t provided_templates = in_templates.Count();
        if (provided_templates > expected_templates) {
            score += kMismatchedTemplateCountPenalty * (provided_templates - expected_templates);
        }
    }

    // Make a mutable copy of the input templates so we can implicitly match more templated
    // arguments.
    TemplateState templates(in_templates);

    // Invoke the matchers for each parameter <-> argument pair.
    // If any arguments cannot be matched, then `score` will be increased.
    // If the overload has any template types or numbers then these will be set based on the
    // argument types. Template types may be refined by constraining with later argument types. For
    // example calling `F<T>(T, T)` with the argument types (abstract-int, i32) will first set T to
    // abstract-int when matching the first argument, and then constrained down to i32 when matching
    // the second argument.
    // Note that inferred template types are not tested against their matchers at this point.
    auto num_params = std::min(num_parameters, num_arguments);
    for (size_t p = 0; p < num_params; p++) {
        auto& parameter = context.data[overload.parameters + p];
        auto* type_indices = context.data[parameter.type_matcher_indices];
        auto* number_indices = context.data[parameter.number_matcher_indices];
        if (!Match(context, templates, overload, type_indices, number_indices, earliest_eval_stage)
                 .Type(args[p]->UnwrapRef())) {
            score += kMismatchedParamTypePenalty;
        }
    }

    if (score == 0) {
        // Check all constrained template types matched their constraint matchers.
        // If the template type *does not* match any of the types in the constraint matcher, then
        // `score` is incremented. If the template type *does* match a type, then the template type
        // is replaced with the first matching type. The order of types in the template matcher is
        // important here, which can be controlled with the [[precedence(N)]] decorations on the
        // types in intrinsics.def.
        for (size_t ot = 0; ot < overload.num_template_types; ot++) {
            auto* matcher_idx = &context.data[overload.template_types + ot].matcher_index;
            if (matcher_idx->IsValid()) {
                if (auto* type = templates.Type(ot)) {
                    if (auto* ty = Match(context, templates, overload, matcher_idx, nullptr,
                                         earliest_eval_stage)
                                       .Type(type)) {
                        // Template type matched one of the types in the template type's matcher.
                        // Replace the template type with this type.
                        templates.SetType(ot, ty);
                        continue;
                    }
                }
                score += kMismatchedTemplateTypePenalty;
            }
        }
    }

    if (score == 0) {
        // Check all constrained open numbers matched.
        // Unlike template types, numbers are not constrained, so we're just checking that the
        // inferred number matches the constraints on the overload. Increments `score` if the
        // template numbers do not match their constraint matchers.
        for (size_t on = 0; on < overload.num_template_numbers; on++) {
            auto* matcher_idx = &context.data[overload.template_numbers + on].matcher_index;
            if (matcher_idx->IsValid()) {
                auto number = templates.Num(on);
                if (!number.IsValid() ||
                    !Match(context, templates, overload, nullptr, matcher_idx, earliest_eval_stage)
                         .Num(number)
                         .IsValid()) {
                    score += kMismatchedTemplateNumberPenalty;
                }
            }
        }
    }

    // Now that all the template types have been finalized, we can construct the parameters.
    Vector<Overload::Parameter, kNumFixedParams> parameters;
    if (score == 0) {
        parameters.Reserve(num_params);
        for (size_t p = 0; p < num_params; p++) {
            auto& parameter = context.data[overload.parameters + p];
            auto* type_indices = context.data[parameter.type_matcher_indices];
            auto* number_indices = context.data[parameter.number_matcher_indices];
            auto* ty = Match(context, templates, overload, type_indices, number_indices,
                             earliest_eval_stage)
                           .Type(args[p]->UnwrapRef());
            parameters.Emplace(ty, parameter.usage);
        }
    }

    return Candidate{&overload, templates, parameters, score};
}

Candidate ResolveCandidate(Context& context,
                           Candidates&& candidates,
                           const char* intrinsic_name,
                           VectorRef<const core::type::Type*> args,
                           TemplateState templates) {
    Vector<uint32_t, kNumFixedParams> best_ranks;
    best_ranks.Resize(args.Length(), 0xffffffff);
    size_t num_matched = 0;
    Candidate* best = nullptr;
    for (auto& candidate : candidates) {
        if (candidate.score > 0) {
            continue;  // Candidate has already been ruled out.
        }
        bool some_won = false;   // An argument ranked less than the 'best' overload's argument
        bool some_lost = false;  // An argument ranked more than the 'best' overload's argument
        for (size_t i = 0; i < args.Length(); i++) {
            auto rank = core::type::Type::ConversionRank(args[i], candidate.parameters[i].type);
            if (best_ranks[i] > rank) {
                best_ranks[i] = rank;
                some_won = true;
            } else if (best_ranks[i] < rank) {
                some_lost = true;
            }
        }
        // If no arguments of this candidate ranked worse than the previous best candidate, then
        // this candidate becomes the new best candidate.
        // If no arguments of this candidate ranked better than the previous best candidate, then
        // this candidate is removed from the list of matches.
        // If neither of the above apply, then we have two candidates with no clear winner, which
        // results in an ambiguous overload error. In this situation the loop ends with
        // `num_matched > 1`.
        if (some_won) {
            // One or more arguments of this candidate ranked better than the previous best
            // candidate's argument(s).
            num_matched++;
            if (!some_lost) {
                // All arguments were at as-good or better than the previous best.
                if (best) {
                    // Mark the previous best candidate as no longer being in the running, by
                    // setting its score to a non-zero value. We pick 1 as this is the closest to 0
                    // (match) as we can get.
                    best->score = 1;
                    num_matched--;
                }
                // This candidate is the new best.
                best = &candidate;
            }
        } else {
            // No arguments ranked better than the current best.
            // Change the score of this candidate to a non-zero value, so that it's not considered a
            // match.
            candidate.score = 1;
        }
    }

    if (num_matched > 1) {
        // Re-sort the candidates with the most promising first
        SortCandidates(candidates);
        // Raise an error
        ErrAmbiguousOverload(context, intrinsic_name, args, templates, candidates);
        return {};
    }

    return std::move(*best);
}

MatchState Match(Context& context,
                 TemplateState& templates,
                 const OverloadInfo& overload,
                 const TypeMatcherIndex* type_matcher_indices,
                 const NumberMatcherIndex* number_matcher_indices,
                 EvaluationStage earliest_eval_stage) {
    return MatchState{context.types,          context.symbols,    templates,
                      context.data,           overload,           type_matcher_indices,
                      number_matcher_indices, earliest_eval_stage};
}

void PrintOverload(StringStream& ss,
                   Context& context,
                   const OverloadInfo& overload,
                   const char* intrinsic_name) {
    TemplateState templates;

    // TODO(crbug.com/tint/1730): Use input evaluation stage to output only relevant overloads.
    auto earliest_eval_stage = EvaluationStage::kConstant;

    ss << intrinsic_name;

    bool print_template_type = false;
    if (overload.num_template_types > 0) {
        if (overload.flags.Contains(OverloadFlag::kIsConverter)) {
            // Print for conversions
            // e.g. vec3<T>(vec3<U>) -> vec3<f32>
            print_template_type = true;
        } else if ((overload.num_parameters == 0) &&
                   overload.flags.Contains(OverloadFlag::kIsConstructor)) {
            // Print for constructors with no params
            // e.g. vec2<T>() -> vec2<T>
            print_template_type = true;
        }
    }
    if (print_template_type) {
        ss << "<";
        ss << context.data[overload.template_types].name;
        ss << ">";
    }
    ss << "(";
    for (size_t p = 0; p < overload.num_parameters; p++) {
        auto& parameter = context.data[overload.parameters + p];
        if (p > 0) {
            ss << ", ";
        }
        if (parameter.usage != ParameterUsage::kNone) {
            ss << ToString(parameter.usage) << ": ";
        }
        auto* type_indices = context.data[parameter.type_matcher_indices];
        auto* number_indices = context.data[parameter.number_matcher_indices];
        ss << Match(context, templates, overload, type_indices, number_indices, earliest_eval_stage)
                  .TypeName();
    }
    ss << ")";
    if (overload.return_type_matcher_indices.IsValid()) {
        ss << " -> ";
        auto* type_indices = context.data[overload.return_type_matcher_indices];
        auto* number_indices = context.data[overload.return_number_matcher_indices];
        ss << Match(context, templates, overload, type_indices, number_indices, earliest_eval_stage)
                  .TypeName();
    }

    bool first = true;
    auto separator = [&] {
        ss << (first ? "  where: " : ", ");
        first = false;
    };
    for (size_t i = 0; i < overload.num_template_types; i++) {
        auto& template_type = context.data[overload.template_types + i];
        if (template_type.matcher_index.IsValid()) {
            separator();
            ss << template_type.name;
            auto* index = &template_type.matcher_index;
            ss << " is "
               << Match(context, templates, overload, index, nullptr, earliest_eval_stage)
                      .TypeName();
        }
    }
    for (size_t i = 0; i < overload.num_template_numbers; i++) {
        auto& template_number = context.data[overload.template_numbers + i];
        if (template_number.matcher_index.IsValid()) {
            separator();
            ss << template_number.name;
            auto* index = &template_number.matcher_index;
            ss << " is "
               << Match(context, templates, overload, nullptr, index, earliest_eval_stage)
                      .NumName();
        }
    }
}

void PrintCandidates(StringStream& ss,
                     Context& context,
                     VectorRef<Candidate> candidates,
                     const char* intrinsic_name) {
    for (auto& candidate : candidates) {
        ss << "  ";
        PrintOverload(ss, context, *candidate.overload, intrinsic_name);
        ss << std::endl;
    }
}

void ErrAmbiguousOverload(Context& context,
                          const char* intrinsic_name,
                          VectorRef<const core::type::Type*> args,
                          TemplateState templates,
                          VectorRef<Candidate> candidates) {
    StringStream ss;
    ss << "ambiguous overload while attempting to match " << intrinsic_name;
    for (size_t i = 0; i < std::numeric_limits<size_t>::max(); i++) {
        if (auto* ty = templates.Type(i)) {
            ss << ((i == 0) ? "<" : ", ") << ty->FriendlyName();
        } else {
            if (i > 0) {
                ss << ">";
            }
            break;
        }
    }
    ss << "(";
    bool first = true;
    for (auto* arg : args) {
        if (!first) {
            ss << ", ";
        }
        first = false;
        ss << arg->FriendlyName();
    }
    ss << "):\n";
    for (auto& candidate : candidates) {
        if (candidate.score == 0) {
            ss << "  ";
            PrintOverload(ss, context, *candidate.overload, intrinsic_name);
            ss << std::endl;
        }
    }
    TINT_ICE() << ss.str();
}

}  // namespace

Result<Overload> Lookup(Context& context,
                        const char* intrinsic_name,
                        size_t function_id,
                        VectorRef<const core::type::Type*> args,
                        EvaluationStage earliest_eval_stage,
                        const Source& source) {
    // Generates an error when no overloads match the provided arguments
    auto on_no_match = [&](VectorRef<Candidate> candidates) {
        StringStream ss;
        ss << "no matching call to " << CallSignature(intrinsic_name, args) << std::endl;
        if (!candidates.IsEmpty()) {
            ss << std::endl
               << candidates.Length() << " candidate function"
               << (candidates.Length() > 1 ? "s:" : ":") << std::endl;
            PrintCandidates(ss, context, candidates, intrinsic_name);
        }
        context.diags.add_error(diag::System::Intrinsics, ss.str(), source);
    };

    // Resolve the intrinsic overload
    return MatchIntrinsic(context, context.data.builtins[function_id], intrinsic_name, args,
                          earliest_eval_stage, TemplateState{}, on_no_match);
}

Result<Overload> Lookup(Context& context,
                        core::UnaryOp op,
                        const core::type::Type* arg,
                        EvaluationStage earliest_eval_stage,
                        const Source& source) {
    const IntrinsicInfo* intrinsic_info = nullptr;
    const char* intrinsic_name = nullptr;
    switch (op) {
        case core::UnaryOp::kComplement:
            intrinsic_info = &context.data.unary_complement;
            intrinsic_name = "operator ~ ";
            break;
        case core::UnaryOp::kNegation:
            intrinsic_info = &context.data.unary_minus;
            intrinsic_name = "operator - ";
            break;
        case core::UnaryOp::kNot:
            intrinsic_info = &context.data.unary_not;
            intrinsic_name = "operator ! ";
            break;
        default:
            TINT_UNREACHABLE() << "invalid unary op: " << op;
            return Failure{};
    }

    Vector args{arg};

    // Generates an error when no overloads match the provided arguments
    auto on_no_match = [&, name = intrinsic_name](VectorRef<Candidate> candidates) {
        StringStream ss;
        ss << "no matching overload for " << CallSignature(name, args) << std::endl;
        if (!candidates.IsEmpty()) {
            ss << std::endl
               << candidates.Length() << " candidate operator"
               << (candidates.Length() > 1 ? "s:" : ":") << std::endl;
            PrintCandidates(ss, context, candidates, name);
        }
        context.diags.add_error(diag::System::Intrinsics, ss.str(), source);
    };

    // Resolve the intrinsic overload
    return MatchIntrinsic(context, *intrinsic_info, intrinsic_name, args, earliest_eval_stage,
                          TemplateState{}, on_no_match);
}

Result<Overload> Lookup(Context& context,
                        core::BinaryOp op,
                        const core::type::Type* lhs,
                        const core::type::Type* rhs,
                        EvaluationStage earliest_eval_stage,
                        const Source& source,
                        bool is_compound) {
    const IntrinsicInfo* intrinsic_info = nullptr;
    const char* intrinsic_name = nullptr;
    switch (op) {
        case core::BinaryOp::kAnd:
            intrinsic_info = &context.data.binary_and;
            intrinsic_name = is_compound ? "operator &= " : "operator & ";
            break;
        case core::BinaryOp::kOr:
            intrinsic_info = &context.data.binary_or;
            intrinsic_name = is_compound ? "operator |= " : "operator | ";
            break;
        case core::BinaryOp::kXor:
            intrinsic_info = &context.data.binary_xor;
            intrinsic_name = is_compound ? "operator ^= " : "operator ^ ";
            break;
        case core::BinaryOp::kLogicalAnd:
            intrinsic_info = &context.data.binary_logical_and;
            intrinsic_name = "operator && ";
            break;
        case core::BinaryOp::kLogicalOr:
            intrinsic_info = &context.data.binary_logical_or;
            intrinsic_name = "operator || ";
            break;
        case core::BinaryOp::kEqual:
            intrinsic_info = &context.data.binary_equal;
            intrinsic_name = "operator == ";
            break;
        case core::BinaryOp::kNotEqual:
            intrinsic_info = &context.data.binary_not_equal;
            intrinsic_name = "operator != ";
            break;
        case core::BinaryOp::kLessThan:
            intrinsic_info = &context.data.binary_less_than;
            intrinsic_name = "operator < ";
            break;
        case core::BinaryOp::kGreaterThan:
            intrinsic_info = &context.data.binary_greater_than;
            intrinsic_name = "operator > ";
            break;
        case core::BinaryOp::kLessThanEqual:
            intrinsic_info = &context.data.binary_less_than_equal;
            intrinsic_name = "operator <= ";
            break;
        case core::BinaryOp::kGreaterThanEqual:
            intrinsic_info = &context.data.binary_greater_than_equal;
            intrinsic_name = "operator >= ";
            break;
        case core::BinaryOp::kShiftLeft:
            intrinsic_info = &context.data.binary_shift_left;
            intrinsic_name = is_compound ? "operator <<= " : "operator << ";
            break;
        case core::BinaryOp::kShiftRight:
            intrinsic_info = &context.data.binary_shift_right;
            intrinsic_name = is_compound ? "operator >>= " : "operator >> ";
            break;
        case core::BinaryOp::kAdd:
            intrinsic_info = &context.data.binary_plus;
            intrinsic_name = is_compound ? "operator += " : "operator + ";
            break;
        case core::BinaryOp::kSubtract:
            intrinsic_info = &context.data.binary_minus;
            intrinsic_name = is_compound ? "operator -= " : "operator - ";
            break;
        case core::BinaryOp::kMultiply:
            intrinsic_info = &context.data.binary_star;
            intrinsic_name = is_compound ? "operator *= " : "operator * ";
            break;
        case core::BinaryOp::kDivide:
            intrinsic_info = &context.data.binary_divide;
            intrinsic_name = is_compound ? "operator /= " : "operator / ";
            break;
        case core::BinaryOp::kModulo:
            intrinsic_info = &context.data.binary_modulo;
            intrinsic_name = is_compound ? "operator %= " : "operator % ";
            break;
    }

    Vector args{lhs, rhs};

    // Generates an error when no overloads match the provided arguments
    auto on_no_match = [&, name = intrinsic_name](VectorRef<Candidate> candidates) {
        StringStream ss;
        ss << "no matching overload for " << CallSignature(name, args) << std::endl;
        if (!candidates.IsEmpty()) {
            ss << std::endl
               << candidates.Length() << " candidate operator"
               << (candidates.Length() > 1 ? "s:" : ":") << std::endl;
            PrintCandidates(ss, context, candidates, name);
        }
        context.diags.add_error(diag::System::Intrinsics, ss.str(), source);
    };

    // Resolve the intrinsic overload
    return MatchIntrinsic(context, *intrinsic_info, intrinsic_name, args, earliest_eval_stage,
                          TemplateState{}, on_no_match);
}

Result<Overload> Lookup(Context& context,
                        CtorConv type,
                        const core::type::Type* template_arg,
                        VectorRef<const core::type::Type*> args,
                        EvaluationStage earliest_eval_stage,
                        const Source& source) {
    auto name = str(type);

    // Generates an error when no overloads match the provided arguments
    auto on_no_match = [&](VectorRef<Candidate> candidates) {
        StringStream ss;
        ss << "no matching constructor for " << CallSignature(name, args, template_arg)
           << std::endl;
        Candidates ctor, conv;
        for (auto candidate : candidates) {
            if (candidate.overload->flags.Contains(OverloadFlag::kIsConstructor)) {
                ctor.Push(candidate);
            } else {
                conv.Push(candidate);
            }
        }
        if (!ctor.IsEmpty()) {
            ss << std::endl
               << ctor.Length() << " candidate constructor" << (ctor.Length() > 1 ? "s:" : ":")
               << std::endl;
            PrintCandidates(ss, context, ctor, name);
        }
        if (!conv.IsEmpty()) {
            ss << std::endl
               << conv.Length() << " candidate conversion" << (conv.Length() > 1 ? "s:" : ":")
               << std::endl;
            PrintCandidates(ss, context, conv, name);
        }
        context.diags.add_error(diag::System::Intrinsics, ss.str(), source);
    };

    // If a template type was provided, then close the 0'th type with this.
    TemplateState templates;
    if (template_arg) {
        templates.Type(0, template_arg);
    }

    // Resolve the intrinsic overload
    return MatchIntrinsic(context, context.data.ctor_conv[static_cast<size_t>(type)], name, args,
                          earliest_eval_stage, templates, on_no_match);
}

}  // namespace tint::core::intrinsic

/// TypeInfo for the Any type declared in the anonymous namespace above
TINT_INSTANTIATE_TYPEINFO(tint::core::intrinsic::Any);