4 files changed, 117 insertions, 3 deletions

diff --git a/crates/rust-analyzer/src/bin/args.rs b/crates/rust-analyzer/src/bin/args.rs
index 3cf394bb4..25367df45 100644
--- a/crates/rust-analyzer/src/bin/args.rs
+++ b/crates/rust-analyzer/src/bin/args.rs
@@ -35,6 +35,10 @@ pub(crate) enum Command {
         what: BenchWhat,
         load_output_dirs: bool,
     },
+    Diagnostics {
+        path: PathBuf,
+        load_output_dirs: bool,
+    },
     RunServer,
     Version,
 }
@@ -209,6 +213,36 @@ ARGS:
                 let load_output_dirs = matches.contains("--load-output-dirs");
                 Command::Bench { path, what, load_output_dirs }
             }
+            "diagnostics" => {
+                if matches.contains(["-h", "--help"]) {
+                    eprintln!(
+                        "\
+ra-cli-diagnostics
+
+USAGE:
+    rust-analyzer diagnostics [FLAGS] [PATH]
+
+FLAGS:
+    -h, --help              Prints help information
+        --load-output-dirs  Load OUT_DIR values by running `cargo check` before analysis
+
+ARGS:
+    <PATH>"
+                    );
+                    return Ok(Err(HelpPrinted));
+                }
+
+                let load_output_dirs = matches.contains("--load-output-dirs");
+                let path = {
+                    let mut trailing = matches.free()?;
+                    if trailing.len() != 1 {
+                        bail!("Invalid flags");
+                    }
+                    trailing.pop().unwrap().into()
+                };
+
+                Command::Diagnostics { path, load_output_dirs }
+            }
             _ => {
                 eprintln!(
                     "\
diff --git a/crates/rust-analyzer/src/bin/main.rs b/crates/rust-analyzer/src/bin/main.rs
index 608f4f67b..4edd617ee 100644
--- a/crates/rust-analyzer/src/bin/main.rs
+++ b/crates/rust-analyzer/src/bin/main.rs
@@ -39,6 +39,10 @@ fn main() -> Result<()> {
             cli::analysis_bench(args.verbosity, path.as_ref(), what, load_output_dirs)?
         }
 
+        args::Command::Diagnostics { path, load_output_dirs } => {
+            cli::diagnostics(path.as_ref(), load_output_dirs)?
+        }
+
         args::Command::RunServer => run_server()?,
         args::Command::Version => println!("rust-analyzer {}", env!("REV")),
     }
diff --git a/crates/rust-analyzer/src/cli.rs b/crates/rust-analyzer/src/cli.rs
index c9738d101..a865a7c7e 100644
--- a/crates/rust-analyzer/src/cli.rs
+++ b/crates/rust-analyzer/src/cli.rs
@@ -3,6 +3,7 @@
 mod load_cargo;
 mod analysis_stats;
 mod analysis_bench;
+mod diagnostics;
 mod progress_report;
 
 use std::io::Read;
@@ -12,6 +13,10 @@ use ra_ide::{file_structure, Analysis};
 use ra_prof::profile;
 use ra_syntax::{AstNode, SourceFile};
 
+pub use analysis_bench::{analysis_bench, BenchWhat, Position};
+pub use analysis_stats::analysis_stats;
+pub use diagnostics::diagnostics;
+
 #[derive(Clone, Copy)]
 pub enum Verbosity {
     Spammy,
@@ -60,9 +65,6 @@ pub fn highlight(rainbow: bool) -> Result<()> {
     Ok(())
 }
 
-pub use analysis_bench::{analysis_bench, BenchWhat, Position};
-pub use analysis_stats::analysis_stats;
-
 fn file() -> Result<SourceFile> {
     let text = read_stdin()?;
     Ok(SourceFile::parse(&text).tree())
diff --git a/crates/rust-analyzer/src/cli/diagnostics.rs b/crates/rust-analyzer/src/cli/diagnostics.rs
new file mode 100644
index 000000000..f5aab89a2
--- /dev/null
+++ b/crates/rust-analyzer/src/cli/diagnostics.rs
@@ -0,0 +1,74 @@
+//! Analyze all files in project for diagnostics. Exits with a non-zero status
+//! code if any errors are found.
+
+use anyhow::anyhow;
+use ra_db::{SourceDatabaseExt, SourceRootId};
+use ra_ide::{Analysis, Severity};
+use std::{collections::HashSet, path::Path};
+
+use crate::cli::{load_cargo::load_cargo, Result};
+use hir::{db::HirDatabase, Crate, Module};
+
+pub fn diagnostics(path: &Path, load_output_dirs: bool) -> Result<()> {
+    let (host, roots) = load_cargo(path, load_output_dirs)?;
+    let db = host.raw_database();
+    let analysis = host.analysis();
+    let members = roots
+        .into_iter()
+        .filter_map(
+            |(source_root_id, project_root)| {
+                if project_root.is_member() {
+                    Some(source_root_id)
+                } else {
+                    None
+                }
+            },
+        )
+        .collect::<HashSet<_>>();
+
+    let mut found_error = false;
+    let mut visited_modules = HashSet::new();
+    for krate in Crate::all(db) {
+        let module = krate.root_module(db).expect("crate without root module");
+        check_module(module, db, &mut visited_modules, &members, &analysis, &mut found_error);
+    }
+
+    println!();
+    println!("diagnostic scan complete");
+
+    if found_error {
+        println!();
+        Err(anyhow!("diagnostic error detected"))
+    } else {
+        Ok(())
+    }
+}
+
+fn check_module(
+    module: Module,
+    db: &(impl HirDatabase + SourceDatabaseExt),
+    visited_modules: &mut HashSet<Module>,
+    members: &HashSet<SourceRootId>,
+    analysis: &Analysis,
+    found_error: &mut bool,
+) {
+    let file_id = module.definition_source(db).file_id.original_file(db);
+    if !visited_modules.contains(&module) {
+        if members.contains(&db.file_source_root(file_id)) {
+            println!("processing: {}", db.file_relative_path(file_id));
+            for diagnostic in analysis.diagnostics(file_id).unwrap() {
+                if matches!(diagnostic.severity, Severity::Error) {
+                    *found_error = true;
+                }
+
+                println!("{:?}", diagnostic);
+            }
+        }
+
+        visited_modules.insert(module);
+
+        for child_module in module.children(db) {
+            check_module(child_module, db, visited_modules, members, analysis, found_error);
+        }
+    }
+}