Package bind (via abigen) doesn't create structs used only as constructor parameters

[ARR4N]

System information

Geth v1.10.12
Should be OS-independent but only tested on Ubuntu
solc 0.8.10+commit.fc410830.Linux.g++

Expected behaviour

Foo.sol

// SPDX-License-Identifier: MIT
pragma solidity >=0.8.0 <0.9.0;

contract Foo {
    struct StructType {
        uint256 field;
    }

    constructor(StructType memory st) {}
}

This should produce a valid binding:
$ solc Foo.sol --combined-json abi,bin | abigen --combined-json /dev/stdin --pkg foo --out foo.go

Actual behaviour

Fatal: Failed to generate ABI binding: template: :71:120: executing "" at <bindtype .Type $structs>: error calling bindtype: runtime error: invalid memory address or nil pointer dereference

Steps to reproduce the behaviour

This test case in bind_test.go:

	{
		name: `constructor with struct param`,
		contract: `
		pragma solidity >=0.8.0 <0.9.0;
		
		contract Foo {
			struct StructType {
				uint256 field;
			}
		
			constructor(StructType memory st) {}
		}
		`,
		bytecode: []string{`0x608060405234801561001057600080fd5b506040516101c43803806101c48339818101604052810190610032919061014a565b50610177565b6000604051905090565b600080fd5b600080fd5b6000601f19601f8301169050919050565b7f4e487b7100000000000000000000000000000000000000000000000000000000600052604160045260246000fd5b6100958261004c565b810181811067ffffffffffffffff821117156100b4576100b361005d565b5b80604052505050565b60006100c7610038565b90506100d3828261008c565b919050565b6000819050919050565b6100eb816100d8565b81146100f657600080fd5b50565b600081519050610108816100e2565b92915050565b60006020828403121561012457610123610047565b5b61012e60206100bd565b9050600061013e848285016100f9565b60008301525092915050565b6000602082840312156101605761015f610042565b5b600061016e8482850161010e565b91505092915050565b603f806101856000396000f3fe6080604052600080fdfea2646970667358221220cdffa667affecefac5561f65f4a4ba914204a8d4eb859d8cd426fb306e5c12a364736f6c634300080a0033`},
		abi:      []string{`[{"inputs":[{"components":[{"internalType":"uint256","name":"field","type":"uint256"}],"internalType":"struct Foo.StructType","name":"st","type":"tuple"}],"stateMutability":"nonpayable","type":"constructor"}]`},
	},

Suspected cause

The nil-pointer dereference is caused by this line not checking if StructType is in the structs map:

go-ethereum/accounts/abi/bind/bind.go

Line 279 in e761255

return structs[kind.TupleRawName+kind.String()].Name

I suspect that the root cause is because structs are detected by this loop over all methods, which excludes the constructor:

go-ethereum/accounts/abi/bind/bind.go

Line 91 in e761255

for _, original := range evmABI.Methods {

[holiman]

Fixed by #23940