Only the first duplicate-definition group is reported per name: `reported.count(i)` is in the loop condition instead of the body

Description

When one name has more than one group of duplicate definitions, only the first group is reported. The remaining duplicates are silently dropped from the diagnostics.

libsolidity/analysis/ContractLevelChecker.cpp:239, in findDuplicateDefinitions<T>:

for (size_t i = 0; i < overloads.size() && !reported.count(i); ++i)

reported holds the indices already covered by an earlier error (populated at :260). The test for it sits in the loop condition, so reaching an already-reported index terminates the entire loop rather than skipping that one index and continuing.

The bookkeeping itself suggests this isn't intended: if the goal were "stop after the first report", a bool would be enough. Maintaining a std::set<size_t> of indices only makes sense if those indices are meant to be skipped when they come round as i — i.e. this looks like a continue written as a loop exit.

Expected: one error per duplicate group.

Actual: one error total, per name.

This is a diagnostics-completeness issue rather than a soundness one, and I'd suggest triaging it as such. Index 0 can never be in reported, so the first group always reports and a contract containing duplicates always fails to compile — nothing invalid is accepted. The cost is that a developer fixes one duplicate, recompiles, and discovers the next.

Environment

• Compiler version: 0.8.36+commit.8a079791 (source byte-identical on current develop; the line dates to d054a3b85, 2018-11-29, which moved it in already written this way)
• Compilation pipeline (legacy, IR, SSA CFG): all — this is in the analysis phase, before codegen
• Target EVM version (as per compiler settings): default (osaka); not EVM-version dependent
• Framework/IDE (e.g. Foundry, Hardhat, Remix): solc command line directly
• EVM execution environment / backend / blockchain client: n/a — compile-time only
• Operating system: macOS 26.5.2

Steps to Reproduce

poc.sol — one name, two independent duplicate groups:

// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.0;

contract C {
    function f(uint) public {}
    function f(uint) public {}
    function f(string memory) public {}
    function f(string memory) public {}
}

solc poc.sol

Expected: two errors — f(uint) is defined twice and f(string) is defined twice, at separate source locations.

Actual: one error.

Error: Function with same name and parameter types defined twice.

Control — identical duplicate structure under two different names reports both, because each name gets its own overloads vector:

contract C {
    function f(uint) public {}
    function f(uint) public {}
    function g(string memory) public {}
    function g(string memory) public {}
}

Error: Function with same name and parameter types defined twice.
Error: Function with same name and parameter types defined twice.

Extent:

The last row reaches EventDefinition (error 5883), since findDuplicateDefinitions is a template used by both checkDuplicateFunctions (:188) and checkDuplicateEvents (:200).