Merge #9138

9138: feat: Implement hover for lints r=Veykril a=Veykril

fixes https://github.com/rust-analyzer/rust-analyzer/issues/8857, fixes https://github.com/rust-analyzer/rust-analyzer/issues/3941

![URXBanNxYe](https://user-images.githubusercontent.com/3757771/120830905-4bd8da80-c55f-11eb-9f55-ff5a321726fa.gif)

We also generate the default lints(and lint groups 🎉) instead now by invoking `rustc -W help` and parsing the output from that.


Co-authored-by: Lukas Wirth <[email protected]>

2 files changed, 73 insertions, 17 deletions

diff --git a/xtask/src/codegen/gen_lint_completions.rs b/xtask/src/codegen/gen_lint_completions.rs
index 24dbc6a39..a28b6cb59 100644
--- a/xtask/src/codegen/gen_lint_completions.rs
+++ b/xtask/src/codegen/gen_lint_completions.rs
@@ -1,4 +1,5 @@
 //! Generates descriptors structure for unstable feature from Unstable Book
+use std::borrow::Cow;
 use std::fmt::Write;
 use std::path::{Path, PathBuf};
 
@@ -12,25 +13,75 @@ pub(crate) fn generate_lint_completions() -> Result<()> {
         cmd!("git clone --depth=1 https://github.com/rust-lang/rust ./target/rust").run()?;
     }
 
-    let mut contents = String::from("use crate::completions::attribute::LintCompletion;\n\n");
-    generate_descriptor(&mut contents, "./target/rust/src/doc/unstable-book/src".into())?;
+    let mut contents = String::from(
+        r#"pub struct Lint {
+    pub label: &'static str,
+    pub description: &'static str,
+}
+
+"#,
+    );
+    generate_lint_descriptor(&mut contents)?;
+    contents.push('\n');
+
+    generate_feature_descriptor(&mut contents, "./target/rust/src/doc/unstable-book/src".into())?;
     contents.push('\n');
 
     cmd!("curl http://rust-lang.github.io/rust-clippy/master/lints.json --output ./target/clippy_lints.json").run()?;
     generate_descriptor_clippy(&mut contents, &Path::new("./target/clippy_lints.json"))?;
     let contents = reformat(&contents)?;
 
-    let destination =
-        project_root().join("crates/ide_completion/src/generated_lint_completions.rs");
+    let destination = project_root().join("crates/ide_db/src/helpers/generated_lints.rs");
     ensure_file_contents(destination.as_path(), &contents)?;
 
     Ok(())
 }
 
-fn generate_descriptor(buf: &mut String, src_dir: PathBuf) -> Result<()> {
-    buf.push_str(r#"pub(super) const FEATURES: &[LintCompletion] = &["#);
+fn generate_lint_descriptor(buf: &mut String) -> Result<()> {
+    let stdout = cmd!("rustc -W help").read()?;
+    let start_lints =
+        stdout.find("----  -------  -------").ok_or_else(|| anyhow::format_err!(""))?;
+    let start_lint_groups =
+        stdout.find("----  ---------").ok_or_else(|| anyhow::format_err!(""))?;
+    let end_lints =
+        stdout.find("Lint groups provided by rustc:").ok_or_else(|| anyhow::format_err!(""))?;
+    let end_lint_groups = stdout
+        .find("Lint tools like Clippy can provide additional lints and lint groups.")
+        .ok_or_else(|| anyhow::format_err!(""))?;
+    buf.push_str(r#"pub const DEFAULT_LINTS: &[Lint] = &["#);
+    buf.push('\n');
+    let mut lints = stdout[start_lints..end_lints]
+        .lines()
+        .skip(1)
+        .filter(|l| !l.is_empty())
+        .map(|line| {
+            let (name, rest) = line.trim().split_once(char::is_whitespace).unwrap();
+            let (_default_level, description) =
+                rest.trim().split_once(char::is_whitespace).unwrap();
+            (name.trim(), Cow::Borrowed(description.trim()))
+        })
+        .collect::<Vec<_>>();
+    lints.extend(
+        stdout[start_lint_groups..end_lint_groups].lines().skip(1).filter(|l| !l.is_empty()).map(
+            |line| {
+                let (name, lints) = line.trim().split_once(char::is_whitespace).unwrap();
+                (name.trim(), format!("lint group for: {}", lints.trim()).into())
+            },
+        ),
+    );
+
+    lints.sort_by(|(ident, _), (ident2, _)| ident.cmp(ident2));
+    lints.into_iter().for_each(|(name, description)| {
+        push_lint_completion(buf, &name.replace("-", "_"), &description)
+    });
+    buf.push_str("];\n");
+    Ok(())
+}
+
+fn generate_feature_descriptor(buf: &mut String, src_dir: PathBuf) -> Result<()> {
+    buf.push_str(r#"pub const FEATURES: &[Lint] = &["#);
     buf.push('\n');
-    ["language-features", "library-features"]
+    let mut vec = ["language-features", "library-features"]
         .iter()
         .flat_map(|it| WalkDir::new(src_dir.join(it)))
         .filter_map(|e| e.ok())
@@ -38,13 +89,16 @@ fn generate_descriptor(buf: &mut String, src_dir: PathBuf) -> Result<()> {
             // Get all `.md ` files
             entry.file_type().is_file() && entry.path().extension().unwrap_or_default() == "md"
         })
-        .for_each(|entry| {
+        .map(|entry| {
             let path = entry.path();
             let feature_ident = path.file_stem().unwrap().to_str().unwrap().replace("-", "_");
             let doc = read_file(path).unwrap();
-
-            push_lint_completion(buf, &feature_ident, &doc);
-        });
+            (feature_ident, doc)
+        })
+        .collect::<Vec<_>>();
+    vec.sort_by(|(feature_ident, _), (feature_ident2, _)| feature_ident.cmp(feature_ident2));
+    vec.into_iter()
+        .for_each(|(feature_ident, doc)| push_lint_completion(buf, &feature_ident, &doc));
     buf.push_str("];\n");
     Ok(())
 }
@@ -85,8 +139,8 @@ fn generate_descriptor_clippy(buf: &mut String, path: &Path) -> Result<()> {
                 .into();
         }
     }
-
-    buf.push_str(r#"pub(super) const CLIPPY_LINTS: &[LintCompletion] = &["#);
+    clippy_lints.sort_by(|lint, lint2| lint.id.cmp(&lint2.id));
+    buf.push_str(r#"pub const CLIPPY_LINTS: &[Lint] = &["#);
     buf.push('\n');
     clippy_lints.into_iter().for_each(|clippy_lint| {
         let lint_ident = format!("clippy::{}", clippy_lint.id);
@@ -102,7 +156,7 @@ fn generate_descriptor_clippy(buf: &mut String, path: &Path) -> Result<()> {
 fn push_lint_completion(buf: &mut String, label: &str, description: &str) {
     writeln!(
         buf,
-        r###"    LintCompletion {{
+        r###"    Lint {{
         label: "{}",
         description: r##"{}"##
     }},"###,
diff --git a/xtask/src/tidy.rs b/xtask/src/tidy.rs
index 618cf12fb..9447d463d 100644
--- a/xtask/src/tidy.rs
+++ b/xtask/src/tidy.rs
@@ -193,7 +193,9 @@ https://github.blog/2015-06-08-how-to-undo-almost-anything-with-git/#redo-after-
 fn deny_clippy(path: &Path, text: &str) {
     let ignore = &[
         // The documentation in string literals may contain anything for its own purposes
-        "ide_completion/src/generated_lint_completions.rs",
+        "ide_db/src/helpers/generated_lints.rs",
+        // The tests test clippy lint hovers
+        "ide/src/hover.rs",
     ];
     if ignore.iter().any(|p| path.ends_with(p)) {
         return;
@@ -280,7 +282,7 @@ fn check_todo(path: &Path, text: &str) {
         // `ast::make`.
         "ast/make.rs",
         // The documentation in string literals may contain anything for its own purposes
-        "ide_completion/src/generated_lint_completions.rs",
+        "ide_db/src/helpers/generated_lints.rs",
     ];
     if need_todo.iter().any(|p| path.ends_with(p)) {
         return;
@@ -310,7 +312,7 @@ fn check_dbg(path: &Path, text: &str) {
         "ide_completion/src/completions/postfix.rs",
         // The documentation in string literals may contain anything for its own purposes
         "ide_completion/src/lib.rs",
-        "ide_completion/src/generated_lint_completions.rs",
+        "ide_db/src/helpers/generated_lints.rs",
         // test for doc test for remove_dbg
         "src/tests/generated.rs",
     ];