[Bug]: Impossible to generate IR: 'list' object has no attribute 'type'

### Describe the issue:

A bit of a rare case, but...

### Code example to reproduce the issue:

```solidity
library Constants {
uint8 constant value = [[1, 2], [3, 4]][0][0];
}
```

### Version:

0.9.1

### Relevant log output:

```shell
Impossible to generate IR for ConstantExpressions.slitherConstructorConstantVariables:
'list' object has no attribute 'type'
```

Start by reproducing the Solidity example from the report and tracing IR generation for ConstantExpressions.slitherConstructorConstantVariables. The report names no source file or test; done means the example no longer fails with 'list' object has no attribute 'type' and IR generation succeeds.

Written by the indexing model from the issue text.