Make code generation just work

Contributors don't need to learn about `cargo xtask codegen` if `cargo
test` just does the right thing.

xtask/src/codegen.rs

@@ -7,9 +7,9 @@
 
 mod gen_syntax;
 mod gen_parser_tests;
+mod gen_lint_completions;
 mod gen_assists_docs;
 mod gen_feature_docs;
-mod gen_lint_completions;
 mod gen_diagnostic_docs;
 
 use std::{
@@ -18,38 +18,35 @@ use std::{
 };
 use xshell::{cmd, pushenv, read_file, write_file};
 
-use crate::{ensure_rustfmt, flags, project_root, Result};
+use crate::{ensure_rustfmt, project_root, Result};
 
 pub(crate) use self::{
-    gen_assists_docs::{generate_assists_docs, generate_assists_tests},
-    gen_diagnostic_docs::generate_diagnostic_docs,
-    gen_feature_docs::generate_feature_docs,
-    gen_lint_completions::generate_lint_completions,
-    gen_parser_tests::generate_parser_tests,
-    gen_syntax::generate_syntax,
+    gen_assists_docs::generate_assists_tests, gen_lint_completions::generate_lint_completions,
+    gen_parser_tests::generate_parser_tests, gen_syntax::generate_syntax,
 };
 
+pub(crate) fn docs() -> Result<()> {
+    // We don't commit docs to the repo, so we can just overwrite them.
+    gen_assists_docs::generate_assists_docs(Mode::Overwrite)?;
+    gen_feature_docs::generate_feature_docs(Mode::Overwrite)?;
+    gen_diagnostic_docs::generate_diagnostic_docs(Mode::Overwrite)?;
+    Ok(())
+}
+
+#[allow(unused)]
+fn used() {
+    generate_parser_tests(Mode::Overwrite);
+    generate_assists_tests(Mode::Overwrite);
+    generate_syntax(Mode::Overwrite);
+    generate_lint_completions(Mode::Overwrite);
+}
+
 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
 pub(crate) enum Mode {
     Overwrite,
     Ensure,
 }
 
-impl flags::Codegen {
-    pub(crate) fn run(self) -> Result<()> {
-        if self.features {
-            generate_lint_completions(Mode::Overwrite)?;
-        }
-        generate_syntax(Mode::Overwrite)?;
-        generate_parser_tests(Mode::Overwrite)?;
-        generate_assists_tests(Mode::Overwrite)?;
-        generate_assists_docs(Mode::Overwrite)?;
-        generate_feature_docs(Mode::Overwrite)?;
-        generate_diagnostic_docs(Mode::Overwrite)?;
-        Ok(())
-    }
-}
-
 /// A helper to update file on disk if it has changed.
 /// With verify = false,
 fn update(path: &Path, contents: &str, mode: Mode) -> Result<()> {

xtask/src/flags.rs

@@ -27,10 +27,6 @@ xflags::xflags! {
             optional --jemalloc
         }
 
-        cmd codegen {
-            optional --features
-        }
-
         cmd lint {}
         cmd fuzz-tests {}
         cmd pre-cache {}
@@ -67,7 +63,6 @@ pub struct Xtask {
 pub enum XtaskCmd {
     Help(Help),
     Install(Install),
-    Codegen(Codegen),
     Lint(Lint),
     FuzzTests(FuzzTests),
     PreCache(PreCache),
@@ -92,11 +87,6 @@ pub struct Install {
     pub jemalloc: bool,
 }
 
-#[derive(Debug)]
-pub struct Codegen {
-    pub features: bool,
-}
-
 #[derive(Debug)]
 pub struct Lint;
 

xtask/src/main.rs

@@ -40,7 +40,6 @@ fn main() -> Result<()> {
             return Ok(());
         }
         flags::XtaskCmd::Install(cmd) => cmd.run(),
-        flags::XtaskCmd::Codegen(cmd) => cmd.run(),
         flags::XtaskCmd::Lint(_) => run_clippy(),
         flags::XtaskCmd::FuzzTests(_) => run_fuzzer(),
         flags::XtaskCmd::PreCache(cmd) => cmd.run(),

xtask/src/release.rs

@@ -2,7 +2,7 @@ use std::fmt::Write;
 
 use xshell::{cmd, cp, pushd, read_dir, write_file};
 
-use crate::{codegen, date_iso, flags, is_release_tag, project_root, Mode, Result};
+use crate::{codegen, date_iso, flags, is_release_tag, project_root, Result};
 
 impl flags::Release {
     pub(crate) fn run(self) -> Result<()> {
@@ -12,8 +12,7 @@ impl flags::Release {
             cmd!("git reset --hard tags/nightly").run()?;
             cmd!("git push").run()?;
         }
-        codegen::generate_assists_docs(Mode::Overwrite)?;
-        codegen::generate_feature_docs(Mode::Overwrite)?;
+        codegen::docs()?;
 
         let website_root = project_root().join("../rust-analyzer.github.io");
         let changelog_dir = website_root.join("./thisweek/_posts");

xtask/src/tidy.rs

@@ -12,31 +12,36 @@ use crate::{
 };
 
 #[test]
-fn generated_grammar_is_fresh() {
+fn generate_grammar() {
     codegen::generate_syntax(Mode::Ensure).unwrap()
 }
 
 #[test]
-fn generated_tests_are_fresh() {
+fn generate_parser_tests() {
     codegen::generate_parser_tests(Mode::Ensure).unwrap()
 }
 
 #[test]
-fn generated_assists_are_fresh() {
+fn generate_assists_tests() {
     codegen::generate_assists_tests(Mode::Ensure).unwrap();
 }
 
+/// This clones rustc repo, and so is not worth to keep up-to-date. We update
+/// manually by un-ignoring the test from time to time.
+#[test]
+#[ignore]
+fn generate_lint_completions() {
+    codegen::generate_lint_completions(Mode::Overwrite).unwrap()
+}
+
 #[test]
 fn check_code_formatting() {
     run_rustfmt(Mode::Ensure).unwrap()
 }
 
 #[test]
-fn smoke_test_docs_generation() {
-    // We don't commit docs to the repo, so we can just overwrite in tests.
-    codegen::generate_assists_docs(Mode::Overwrite).unwrap();
-    codegen::generate_feature_docs(Mode::Overwrite).unwrap();
-    codegen::generate_diagnostic_docs(Mode::Overwrite).unwrap();
+fn smoke_test_generate_documentation() {
+    codegen::docs().unwrap()
 }
 
 #[test]