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TypeChecker: reject zero-length static array element types #16718

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TypeChecker: reject zero-length static array element types #16718

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10 changes: 10 additions & 0 deletions libsolidity/analysis/TypeChecker.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3634,7 +3634,17 @@ bool TypeChecker::visit(IndexAccess const& _access)
if (expectType(*index, *TypeProvider::uint256()))
{
if (auto indexValue = dynamic_cast<RationalNumberType const*>(type(*index)))
{
// Mirror the zero-length rejection from
// DeclarationTypeChecker::endVisit(ArrayTypeName). Static array types
// written as expressions (e.g. inside `abi.decode((T[0][]))`) never
// go through that visitor, so without this guard the zero-length
// element type propagates to codegen and triggers an ICE in
// callers that assume `calldataStride() > 0`.
if (indexValue->value() == 0)
m_errorReporter.fatalTypeError(1406_error, index->location(), "Array with zero length specified.");
length = indexValue->literalValue(nullptr);
}
else
m_errorReporter.fatalTypeError(3940_error, index->location(), "Integer constant expected.");
}
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9 changes: 9 additions & 0 deletions test/libsolidity/syntaxTests/array/length/abi_decode_zero_length_element.sol
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Original file line number Diff line number Diff line change
@@ -0,0 +1,9 @@
// Used to cause ICE in ABIFunctions::abiDecodingFunctionArrayAvailableLength
// when a dynamic array's element type was a zero-length static array.
contract C {
function f(bytes memory b) public pure {
abi.decode(b, (uint256[0][]));
}
}
// ----
// TypeError 1406: (146-147): Array with zero length specified.