go/parser: remove validation of expression syntax, leave to type checker
Remove the code that verifies that an expression is a type or non-type
expression. For one, it cannot be done perfectly accurate
(e.g., consider *p which could be an indirection or a pointer type),
it also unnecessarily slows down parsing. It's simpler to leave the
verification to the type checker which has all the information needed.
Remove short compiler tests that tested the expression/type property.
Adjust a couple of go/types tests which now trigger because the parser
doesn't complain anymore.
Change file for benchmark from "parser.go" to "../printer/nodes.go"
to avoid a moving target when benchmarking.
The parser may be marginally faster when tested on nodes.go:
name old time/op new time/op delta
ParseOnly-12 1.35ms ± 0% 1.31ms ± 0% ~ (p=0.100 n=3+3)
name old speed new speed delta
ParseOnly-12 39.9MB/s ± 0% 41.0MB/s ± 0% ~ (p=0.100 n=3+3)
For #54511.
Change-Id: I9a32c24c2c6e843c3d1af4587651c352f378b490
Reviewed-on: https://go-review.googlesource.com/c/go/+/425716 Reviewed-by: Robert Griesemer <gri@google.com>
Run-TryBot: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Alan Donovan <adonovan@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>