jyn jyn514

Item	Instantiation count	Estimated Cost Per Instantiation	Total Estimated Cost
std::thread::LocalKey::::try_with	3214	58	186412
hashbrown::raw::RawTable::<T, A>::reserve_rehash	277	402	111354
rustc_query_system::query::plumbing::try_load_from_disk_and_cache_in_memory	228	449	102372
rustc_query_system::dep_graph::DepGraph::::with_task_impl	228	391	89148
rustc_query_system::query::plumbing::execute_job	228	376	85728
rustc_middle::ty::tls::with_context_opt	1599	53	84747
plumbing::force_from_dep_node	285	296	84360
std::ptr::const_ptr::::is_aligned_to	1722	46	79212

(I plan to publish this as a blog post once a few people have looked at it and caught the obvious typos.)

I got lots of positive feedback about the FAQ section in my Rust 2020 blog post, so I'm trying that format again for another topic that's been requested a lot: How to fix common borrow-checker issues. This isn't meant to explain how or why the borrow checker works the way it does (see The Nomicon or Two Beautiful Rust Programs for that), just how to work around some of its current limitations.

Projects

The main projects I work on are docs.rs, saltwater cc, and the rust compiler itself.

Hardware

Normally I compile on my laptop, which is a 4 core 7th gen i5 with 8 GB memory. When I started working on rustc itself, that was unbearably slow (over 45 minutes for a stage 1 build),

A builtin-macro was attempted to be registered twice.

Erroneous code example:

#![feature(decl_macro)]
#![feature(rustc_attrs)]

#[rustc_builtin_macro]
pub macro test($item:item) {

layout	title	date	audience	excerpt
post	the-intra-doc-links-saga	2020-08-08 00:01:14 -0400	developers

N.B. This post assumes some familiarity with [the Rust programming language][rust].

	[
	{"name":"std::thread::LocalKey::<T>::try_with","instantiation_count":3214,"size_estimate":58,"total_estimate":186412},
	{"name":"hashbrown::raw::RawTable::<T, A>::reserve_rehash","instantiation_count":277,"size_estimate":402,"total_estimate":111354},
	{"name":"rustc_query_system::query::plumbing::try_load_from_disk_and_cache_in_memory","instantiation_count":228,"size_estimate":449,"total_estimate":102372},
	{"name":"rustc_query_system::dep_graph::DepGraph::<K>::with_task_impl","instantiation_count":228,"size_estimate":391,"total_estimate":89148},
	{"name":"rustc_query_system::query::plumbing::execute_job","instantiation_count":228,"size_estimate":376,"total_estimate":85728},
	{"name":"rustc_middle::ty::tls::with_context_opt","instantiation_count":1599,"size_estimate":53,"total_estimate":84747},
	{"name":"plumbing::force_from_dep_node","instantiation_count":285,"size_estimate":296,"total_estimate":84360},
	{"name":"std::ptr::const_ptr::<impl *const T>::is_aligned_to","instantiation_count":1722,"size_estimate":46,"t

	import sys
	from collections import defaultdict, Counter

	def lexer():
	for line in sys.stdin:
	for token in line.split():
	yield token

	def lookup(var, scope):
	while scope.get(var):

	error[E0433]: failed to resolve: could not find `handle` in `sys`
	--> library/std/src/sys/windows/ext/process.rs:13:27
	\|
	13 \| let handle = sys::handle::Handle::new(handle as *mut _);
	\| ^^^^^^ could not find `handle` in `sys`

	error[E0425]: cannot find function `symlink_inner` in module `sys::fs`
	--> library/std/src/sys/windows/ext/fs.rs:544:14
	\|
	544 \| sys::fs::symlink_inner(src.as_ref(), dst.as_ref(), false)

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