3 files changed, 45 insertions, 19 deletions

diff --git a/crates/stdx/Cargo.toml b/crates/stdx/Cargo.toml
index f9e380c10..4c0b85861 100644
--- a/crates/stdx/Cargo.toml
+++ b/crates/stdx/Cargo.toml
@@ -3,6 +3,7 @@ name = "stdx"
 version = "0.1.0"
 authors = ["rust-analyzer developers"]
 edition = "2018"
+license = "MIT OR Apache-2.0"
 
 [lib]
 doctest = false
diff --git a/crates/stdx/src/lib.rs b/crates/stdx/src/lib.rs
index 08ac6f70f..988853ed2 100644
--- a/crates/stdx/src/lib.rs
+++ b/crates/stdx/src/lib.rs
@@ -1,30 +1,13 @@
 //! Missing batteries for standard libraries.
 use std::{cell::Cell, fmt, time::Instant};
 
+mod macros;
+
 #[inline(always)]
 pub fn is_ci() -> bool {
     option_env!("CI").is_some()
 }
 
-#[macro_export]
-macro_rules! eprintln {
-    ($($tt:tt)*) => {{
-        if $crate::is_ci() {
-            panic!("Forgot to remove debug-print?")
-        }
-        std::eprintln!($($tt)*)
-    }}
-}
-
-/// Appends formatted string to a `String`.
-#[macro_export]
-macro_rules! format_to {
-    ($buf:expr) => ();
-    ($buf:expr, $lit:literal $($arg:tt)*) => {
-        { use ::std::fmt::Write as _; let _ = ::std::write!($buf, $lit $($arg)*); }
-    };
-}
-
 pub trait SepBy: Sized {
     /// Returns an `impl fmt::Display`, which joins elements via a separator.
     fn sep_by<'a>(self, sep: &'a str) -> SepByBuilder<'a, Self>;
@@ -87,6 +70,8 @@ where
         Ok(())
     }
 }
+
+#[must_use]
 pub fn timeit(label: &'static str) -> impl Drop {
     struct Guard {
         label: &'static str,
diff --git a/crates/stdx/src/macros.rs b/crates/stdx/src/macros.rs
new file mode 100644
index 000000000..bf298460f
--- /dev/null
+++ b/crates/stdx/src/macros.rs
@@ -0,0 +1,40 @@
+//! Convenience macros.
+#[macro_export]
+macro_rules! eprintln {
+    ($($tt:tt)*) => {{
+        if $crate::is_ci() {
+            panic!("Forgot to remove debug-print?")
+        }
+        std::eprintln!($($tt)*)
+    }}
+}
+
+/// Appends formatted string to a `String`.
+#[macro_export]
+macro_rules! format_to {
+    ($buf:expr) => ();
+    ($buf:expr, $lit:literal $($arg:tt)*) => {
+        { use ::std::fmt::Write as _; let _ = ::std::write!($buf, $lit $($arg)*); }
+    };
+}
+
+// Generates `From` impls for `Enum E { Foo(Foo), Bar(Bar) }` enums
+#[macro_export]
+macro_rules! impl_from {
+    ($($variant:ident $(($($sub_variant:ident),*))?),* for $enum:ident) => {
+        $(
+            impl From<$variant> for $enum {
+                fn from(it: $variant) -> $enum {
+                    $enum::$variant(it)
+                }
+            }
+            $($(
+                impl From<$sub_variant> for $enum {
+                    fn from(it: $sub_variant) -> $enum {
+                        $enum::$variant($variant::$sub_variant(it))
+                    }
+                }
+            )*)?
+        )*
+    }
+}