2 files changed, 25 insertions, 4 deletions

diff --git a/crates/ra_tools/Cargo.toml b/crates/ra_tools/Cargo.toml
index a40a452aa..4c9aa1cc3 100644
--- a/crates/ra_tools/Cargo.toml
+++ b/crates/ra_tools/Cargo.toml
@@ -6,7 +6,6 @@ authors = ["rust-analyzer developers"]
 publish = false
 
 [dependencies]
-teraron = "0.1.0"
 walkdir = "2.1.3"
 itertools = "0.8.0"
 clap = "2.32.0"
diff --git a/crates/ra_tools/src/lib.rs b/crates/ra_tools/src/lib.rs
index de8c472d1..c02dee953 100644
--- a/crates/ra_tools/src/lib.rs
+++ b/crates/ra_tools/src/lib.rs
@@ -11,8 +11,6 @@ use std::{
 
 use itertools::Itertools;
 
-pub use teraron::{Mode, Overwrite, Verify};
-
 pub use self::codegen::generate;
 
 pub type Result<T> = std::result::Result<T, Box<dyn Error>>;
@@ -26,6 +24,13 @@ pub const SYNTAX_KINDS: &str = "crates/ra_parser/src/syntax_kind/generated.rs.te
 pub const AST: &str = "crates/ra_syntax/src/ast/generated.rs";
 const TOOLCHAIN: &str = "stable";
 
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+pub enum Mode {
+    Overwrite,
+    Verify,
+}
+pub use Mode::*;
+
 #[derive(Debug)]
 pub struct Test {
     pub name: String,
@@ -222,7 +227,7 @@ pub fn gen_tests(mode: Mode) -> Result<()> {
                     tests_dir.join(file_name)
                 }
             };
-            teraron::update(&path, &test.text, mode)?;
+            update(&path, &test.text, mode)?;
         }
         Ok(())
     }
@@ -306,3 +311,20 @@ fn existing_tests(dir: &Path, ok: bool) -> Result<HashMap<String, (PathBuf, Test
     }
     Ok(res)
 }
+
+/// A helper to update file on disk if it has changed.
+/// With verify = false,
+pub fn update(path: &Path, contents: &str, mode: Mode) -> Result<()> {
+    match fs::read_to_string(path) {
+        Ok(ref old_contents) if old_contents == contents => {
+            return Ok(());
+        }
+        _ => (),
+    }
+    if mode == Verify {
+        Err(format!("`{}` is not up-to-date", path.display()))?;
+    }
+    eprintln!("updating {}", path.display());
+    fs::write(path, contents)?;
+    Ok(())
+}