`TypeInferenceError` with parametrized structs

[mtdudek]

Describe the bug When parametrized function returns parametrized struct as an function value, parser/type checker fails with TypeInferenceError.

0037: #[quickcheck]
0038: fn prop_double_reverse(x: bits[WeightPreScanInternalDataSize(u32:8)]) -> bool {
0039:   x == InternalStructToBits<u32:8>(BitsToInternalStruct<u32:8>(x))
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^--------^ TypeInferenceError: WeightPreScanInternalData { occurance_count: uN[COUNTER_WIDTH][8], valid_weigths: uN[1][12], weights_count: uN[COUNTER_WIDTH][12] } Instantiated return type did not have all parametrics resolved.
0040: }

Struct has inferred parameters that aren't resolved during InstantiateParametricFunction.

Code that triggers this bug:

import std;

const MAX_WEIGTH = u32:11;
const WEIGTH_LOG = std::clog2(MAX_WEIGTH);
const MAX_SYMBOL_COUNT = u32:256;

struct WeightPreScanInternalData <
    PARALLEL_ACCESS_WIDTH: u32,
    COUNTER_WIDTH: u32 = {std::clog2(PARALLEL_ACCESS_WIDTH + u32:1)}
> {
    occurance_count: uN[COUNTER_WIDTH][PARALLEL_ACCESS_WIDTH],
    valid_weigths:   u1[MAX_WEIGTH + u32:1],
    weights_count:   uN[COUNTER_WIDTH][MAX_WEIGTH + u32:1],
}

fn WeightPreScanInternalDataSize(PARALLEL_ACCESS_WIDTH: u32) -> u32 {
    let COUNTER_WIDTH = {std::clog2(PARALLEL_ACCESS_WIDTH + u32:1)};
    (COUNTER_WIDTH as u32) * (PARALLEL_ACCESS_WIDTH as u32) +
    (MAX_WEIGTH as u32) + u32:1 +
    (COUNTER_WIDTH as u32) * (MAX_WEIGTH as u32 + u32:1)
}

fn InternalStructToBits<
    PARALLEL_ACCESS_WIDTH: u32,
    BITS: u32 = {WeightPreScanInternalDataSize(PARALLEL_ACCESS_WIDTH)}
> (internalStruct: WeightPreScanInternalData<PARALLEL_ACCESS_WIDTH>) -> bits[BITS] {
    internalStruct as bits[BITS]
}

fn BitsToInternalStruct<
    PARALLEL_ACCESS_WIDTH: u32,
    BITS: u32 = {WeightPreScanInternalDataSize(PARALLEL_ACCESS_WIDTH)}
> (rawBits: bits[BITS]) -> WeightPreScanInternalData<PARALLEL_ACCESS_WIDTH> {
    rawBits as WeightPreScanInternalData<PARALLEL_ACCESS_WIDTH>
}

#[quickcheck]
fn prop_double_reverse(x: bits[WeightPreScanInternalDataSize(u32:8)]) -> bool {
  x == InternalStructToBits<u32:8>(BitsToInternalStruct<u32:8>(x))
}

//#[quickcheck]
//fn prop_double_reverse(x: WeightPreScanInternalData<u32:8>) -> bool {
//  x == BitsToInternalStruct<u32:8>(InternalStructToBits<u32:8>(x))
//}

Switching order of function calls results

#[quickcheck]
fn prop_double_reverse(x: WeightPreScanInternalData<u32:8>) -> bool {
  x == BitsToInternalStruct<u32:8>(InternalStructToBits<u32:8>(x))
}

in the following error:

E0730 22:10:37.766863 2828959 parametric_bind.cc:112] INTERNAL: XLS_RET_CHECK failure (xls/dslx/type_system/parametric_bind.cc:112) !arg_dim.IsParametric() COUNTER_WIDTH
0x5617ebeb0a6a: xabsl::StatusBuilder::CreateStatusAndConditionallyLog()
0x5617e9ee2719: xabsl::StatusBuilder::operator absl::lts_20240116::Status()
0x5617e9fe4228: xls::dslx::ParametricBindTypeDim()
0x5617e9fe4a8b: xls::dslx::ParametricBind()
0x5617e9fe4d85: xls::dslx::ParametricBind()
0x5617e9fe4eab: xls::dslx::ParametricBind()
0x5617e9fdc9a6: xls::dslx::internal::ParametricInstantiator::InstantiateOneArg()
0x5617e9fdd486: xls::dslx::internal::FunctionInstantiator::Instantiate()
0x5617e9fda883: xls::dslx::InstantiateFunction()
0x5617e9f79f15: xls::dslx::InstantiateParametricFunction()
0x5617e9f70474: xls::dslx::TypecheckInvocation()
0x5617e9f66b78: std::__1::__function::__func<>::operator()()
0x5617e9fc8d1e: xls::dslx::DeduceInstantiation()
0x5617e9fc9cde: xls::dslx::DeduceInvocation()
0x5617e9fa6a8b: xls::dslx::(anonymous namespace)::DeduceVisitor::HandleInvocation()
0x5617ea3d686b: xls::dslx::Invocation::Accept()
0x5617e9f9ac7f: xls::dslx::Deduce()
0x5617e9f668b5: std::__1::__function::__func<>::operator()()
0x5617ea0601a8: xls::dslx::DeduceCtx::Deduce()
0x5617e9f9b1f2: xls::dslx::DeduceAndResolve()
0x5617e9fc9031: xls::dslx::AppendArgsForInstantiation()
0x5617e9fc9c54: xls::dslx::DeduceInvocation()
0x5617e9fa6a8b: xls::dslx::(anonymous namespace)::DeduceVisitor::HandleInvocation()
0x5617ea3d686b: xls::dslx::Invocation::Accept()
0x5617e9f9ac7f: xls::dslx::Deduce()
0x5617e9f668b5: std::__1::__function::__func<>::operator()()
0x5617ea0601a8: xls::dslx::DeduceCtx::Deduce()
0x5617e9f9b1f2: xls::dslx::DeduceAndResolve()
0x5617e9fc505a: xls::dslx::DeduceBinop()
0x5617e9fa117b: xls::dslx::(anonymous namespace)::DeduceVisitor::HandleBinop()
0x5617ea3d6f7b: xls::dslx::Binop::Accept()
0x5617e9f9ac7f: xls::dslx::Deduce()
0x5617e9f668b5: std::__1::__function::__func<>::operator()()
0x5617ea0601a8: xls::dslx::DeduceCtx::Deduce()
0x5617e9f9db94: xls::dslx::(anonymous namespace)::DeduceVisitor::HandleStatement()
0x5617ea3d789b: xls::dslx::Statement::Accept()
0x5617e9f9ac7f: xls::dslx::Deduce()
0x5617e9f668b5: std::__1::__function::__func<>::operator()()
0x5617ea0601a8: xls::dslx::DeduceCtx::Deduce()
0x5617e9fa12c8: xls::dslx::(anonymous namespace)::DeduceVisitor::HandleStatementBlock()
0x5617ea3d70ab: xls::dslx::StatementBlock::Accept()
0x5617e9f9ac7f: xls::dslx::Deduce()
0x5617e9f668b5: std::__1::__function::__func<>::operator()()
0x5617ea0601a8: xls::dslx::DeduceCtx::Deduce()
0x5617e9f9b1f2: xls::dslx::DeduceAndResolve()
0x5617e9f6b324: xls::dslx::TypecheckFunction()
0x5617e9f63b2f: xls::dslx::TypecheckModule()
0x5617e9ef2897: xls::dslx::TypecheckModule()
0x5617e9ef1d5c: xls::dslx::ParseAndTypecheck()
0x5617e9ee7652: xls::dslx::ParseAndTest()

E0730 22:10:37.766977 2828959 command_line_utils.cc:46] Could not extract a textual position from error message: INTERNAL: XLS_RET_CHECK failure (xls/dslx/type_system/parametric_bind.cc:112) !arg_dim.IsParametric() COUNTER_WIDTH: INVALID_ARGUMENT: Provided status is not in recognized error form: INTERNAL: XLS_RET_CHECK failure (xls/dslx/type_system/parametric_bind.cc:112) !arg_dim.IsParametric() COUNTER_WIDTH

To Reproduce Steps to reproduce the behavior:

1. Build interpreter_main
2. Copy attached code into file.x
3. Run interpreter_main file.x
4. Observe error message(s)

Expected behavior Interpreter should correctly deduce types for parametric structs.

Environment (this can be helpful for troubleshooting):

• OS: Debian
• Versions 12

Additional context Tested on the newest available main(ea5c4dc24d50951374089c6727ca610e919d124a) I've already looked into code base for function instantiation, and it doesn't check if return or argument types contain parametrized structs. That unfortunately leads to the EagerlyPopulateParametricEnvMap missing struct inferred parameters. I' wonder if adding extra step in the InstantiateParametricFunction (

• iterates over function args and return type
• checks for parametric structs
• add their parameters to typed_parametrics ) would fix this issue.

[mtdudek]

I've discovered more things regarding parameters in structs:

• non-explicit parameters that use {} syntax aren't evaluated in ConcretizeStructAnnotation,
• there is no class that inherits from ParametricExpression that is used to represent {} statements,
• evaluation on the parameters in the ConcretizeStructAnnotation is a bit confusing, as parameters are scanned in order, but evaluation has access to all parameters at once.