Currently our logic for reflective methods like Object#instance_variable_get, Struct#[], etc goes like this:

• If it's a symbol, look up the value
• If it's a string, turn it into a hard symbol and look up the value

The logic we need to match in MRI is as follows:

• If it's a symbol, look up the value
• If it's a string, see if a symbol exists for that string
• If there is no such symbol, do not create it and do not search (return nil)

MRI only creates symbols for nonexistent key strings passed to the write methods, like instance_variable_set. Our logic has the following issues that should be addressed in some way before 9.2 (or if possible, we should match MRI's logic exactly):

• Hard symbols will leak. This means arbitrary strings passed into reflective read methods could cause a symbol leak.
• Soft symbols pollute the symbol table but would not introduce a symbol leak.

In general MRI will assume that if a string is passed in, and no such symbol exists, no such entry can exists in whatever is being searched.