The goal here is to make the representation more uniform so that we can
start adding different kinds of binding -- checked generic bindings and
template bindings -- across both function parameters and local `let`
declarations.
With this change, the entry in the parameter list for the function is
the name binding, not the Param itself, which has some ripple effects on
consumers of that list that want to access the parameter rather than the
binding. This is expected to change again when we start adding more of
the pattern matching SemIR, but this seems good enough for now.
Another incremental change to diagnostic formatting. I simply recurse
over all the tokens in the subtree of a parse node and construct a
`DiagnosticLocation` that covers all of the tokens.
I believe it's nicer for the user to be directed at the entire chunk of
source where the error is occurring rather then just pointing at the
bracketing/terminator tokens, but let me know if you all agree.
Most of the calls to `StringifyType` already passed `true` for
`in_type_context`. Checking the rest, I found that every one of them was
already sufficiently clear that they were printing a type, or could be
made so with a very small change to the diagnostic text.
Richard Smith
Jacob Schneider
Geoff RomerandRichard Smith
josh11bandJon Ross-Perkins