5 files changed, 83 insertions, 11 deletions

diff --git a/xtask/src/codegen/gen_assists_docs.rs b/xtask/src/codegen/gen_assists_docs.rs
index ff307e2aa..d7c85ebe9 100644
--- a/xtask/src/codegen/gen_assists_docs.rs
+++ b/xtask/src/codegen/gen_assists_docs.rs
@@ -1,6 +1,6 @@
 //! Generates `assists.md` documentation.
 
-use std::{fmt, fs, path::Path};
+use std::{fmt, path::Path};
 
 use crate::{
     codegen::{self, extract_comment_blocks_with_empty_lines, reformat, Location, Mode, PREAMBLE},
@@ -39,7 +39,7 @@ impl Assist {
         return Ok(res);
 
         fn collect_file(acc: &mut Vec<Assist>, path: &Path) -> Result<()> {
-            let text = fs::read_to_string(path)?;
+            let text = xshell::read_file(path)?;
             let comment_blocks = extract_comment_blocks_with_empty_lines("Assist", &text);
 
             for block in comment_blocks {
diff --git a/xtask/src/codegen/gen_diagnostic_docs.rs b/xtask/src/codegen/gen_diagnostic_docs.rs
new file mode 100644
index 000000000..00aaea5b7
--- /dev/null
+++ b/xtask/src/codegen/gen_diagnostic_docs.rs
@@ -0,0 +1,74 @@
+//! Generates `assists.md` documentation.
+
+use std::{fmt, path::PathBuf};
+
+use crate::{
+    codegen::{self, extract_comment_blocks_with_empty_lines, Location, Mode, PREAMBLE},
+    project_root, rust_files, Result,
+};
+
+pub fn generate_diagnostic_docs(mode: Mode) -> Result<()> {
+    let diagnostics = Diagnostic::collect()?;
+    let contents =
+        diagnostics.into_iter().map(|it| it.to_string()).collect::<Vec<_>>().join("\n\n");
+    let contents = format!("//{}\n{}\n", PREAMBLE, contents.trim());
+    let dst = project_root().join("docs/user/generated_diagnostic.adoc");
+    codegen::update(&dst, &contents, mode)?;
+    Ok(())
+}
+
+#[derive(Debug)]
+struct Diagnostic {
+    id: String,
+    location: Location,
+    doc: String,
+}
+
+impl Diagnostic {
+    fn collect() -> Result<Vec<Diagnostic>> {
+        let mut res = Vec::new();
+        for path in rust_files(&project_root()) {
+            collect_file(&mut res, path)?;
+        }
+        res.sort_by(|lhs, rhs| lhs.id.cmp(&rhs.id));
+        return Ok(res);
+
+        fn collect_file(acc: &mut Vec<Diagnostic>, path: PathBuf) -> Result<()> {
+            let text = xshell::read_file(&path)?;
+            let comment_blocks = extract_comment_blocks_with_empty_lines("Diagnostic", &text);
+
+            for block in comment_blocks {
+                let id = block.id;
+                if let Err(msg) = is_valid_diagnostic_name(&id) {
+                    panic!("invalid diagnostic name: {:?}:\n  {}", id, msg)
+                }
+                let doc = block.contents.join("\n");
+                let location = Location::new(path.clone(), block.line);
+                acc.push(Diagnostic { id, location, doc })
+            }
+
+            Ok(())
+        }
+    }
+}
+
+fn is_valid_diagnostic_name(diagnostic: &str) -> Result<(), String> {
+    let diagnostic = diagnostic.trim();
+    if diagnostic.find(char::is_whitespace).is_some() {
+        return Err("Diagnostic names can't contain whitespace symbols".into());
+    }
+    if diagnostic.chars().any(|c| c.is_ascii_uppercase()) {
+        return Err("Diagnostic names can't contain uppercase symbols".into());
+    }
+    if diagnostic.chars().any(|c| !c.is_ascii()) {
+        return Err("Diagnostic can't contain non-ASCII symbols".into());
+    }
+
+    Ok(())
+}
+
+impl fmt::Display for Diagnostic {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        writeln!(f, "=== {}\n**Source:** {}\n{}", self.id, self.location, self.doc)
+    }
+}
diff --git a/xtask/src/codegen/gen_feature_docs.rs b/xtask/src/codegen/gen_feature_docs.rs
index 341e67c73..065dd33f1 100644
--- a/xtask/src/codegen/gen_feature_docs.rs
+++ b/xtask/src/codegen/gen_feature_docs.rs
@@ -1,6 +1,6 @@
 //! Generates `assists.md` documentation.
 
-use std::{fmt, fs, path::PathBuf};
+use std::{fmt, path::PathBuf};
 
 use crate::{
     codegen::{self, extract_comment_blocks_with_empty_lines, Location, Mode, PREAMBLE},
@@ -33,7 +33,7 @@ impl Feature {
         return Ok(res);
 
         fn collect_file(acc: &mut Vec<Feature>, path: PathBuf) -> Result<()> {
-            let text = fs::read_to_string(&path)?;
+            let text = xshell::read_file(&path)?;
             let comment_blocks = extract_comment_blocks_with_empty_lines("Feature", &text);
 
             for block in comment_blocks {
diff --git a/xtask/src/codegen/gen_features.rs b/xtask/src/codegen/gen_features.rs
index b58c4a0c9..3cf15ce02 100644
--- a/xtask/src/codegen/gen_features.rs
+++ b/xtask/src/codegen/gen_features.rs
@@ -3,15 +3,13 @@ use std::path::{Path, PathBuf};
 
 use quote::quote;
 use walkdir::WalkDir;
+use xshell::{cmd, read_file};
 
-use crate::{
-    codegen::{project_root, reformat, update, Mode, Result},
-    not_bash::{fs2, run},
-};
+use crate::codegen::{project_root, reformat, update, Mode, Result};
 
 pub fn generate_features(mode: Mode) -> Result<()> {
     if !Path::new("./target/rust").exists() {
-        run!("git clone https://github.com/rust-lang/rust ./target/rust")?;
+        cmd!("git clone https://github.com/rust-lang/rust ./target/rust").run()?;
     }
 
     let contents = generate_descriptor("./target/rust/src/doc/unstable-book/src".into())?;
@@ -34,7 +32,7 @@ fn generate_descriptor(src_dir: PathBuf) -> Result<String> {
         .map(|entry| {
             let path = entry.path();
             let feature_ident = path.file_stem().unwrap().to_str().unwrap().replace("-", "_");
-            let doc = fs2::read_to_string(path).unwrap();
+            let doc = read_file(path).unwrap();
 
             quote! { LintCompletion { label: #feature_ident, description: #doc } }
         });
diff --git a/xtask/src/codegen/gen_parser_tests.rs b/xtask/src/codegen/gen_parser_tests.rs
index 96fdd9216..19ae949d4 100644
--- a/xtask/src/codegen/gen_parser_tests.rs
+++ b/xtask/src/codegen/gen_parser_tests.rs
@@ -124,7 +124,7 @@ fn existing_tests(dir: &Path, ok: bool) -> Result<HashMap<String, (PathBuf, Test
             let file_name = path.file_name().unwrap().to_str().unwrap();
             file_name[5..file_name.len() - 3].to_string()
         };
-        let text = fs::read_to_string(&path)?;
+        let text = xshell::read_file(&path)?;
         let test = Test { name: name.clone(), text, ok };
         if let Some(old) = res.insert(name, (path, test)) {
             println!("Duplicate test: {:?}", old);