document almost all assists

7 files changed, 359 insertions, 183 deletions

diff --git a/crates/ra_assists/src/assists/raw_string.rs b/crates/ra_assists/src/assists/raw_string.rs
index ea756d1ca..2df48a838 100644
--- a/crates/ra_assists/src/assists/raw_string.rs
+++ b/crates/ra_assists/src/assists/raw_string.rs
@@ -1,5 +1,3 @@
-//! FIXME: write short doc here
-
 use hir::db::HirDatabase;
 use ra_syntax::{
     SyntaxKind::{RAW_STRING, STRING},
@@ -9,6 +7,21 @@ use rustc_lexer;
 
 use crate::{Assist, AssistCtx, AssistId};
 
+// Assist: make_raw_string
+//
+// Adds `r#` to a plain string literal.
+//
+// ```
+// fn main() {
+//     "Hello,<|> World!";
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     r#"Hello, World!"#;
+// }
+// ```
 pub(crate) fn make_raw_string(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
     let token = ctx.find_token_at_offset(STRING)?;
     let text = token.text().as_str();
@@ -40,6 +53,21 @@ pub(crate) fn make_raw_string(mut ctx: AssistCtx<impl HirDatabase>) -> Option<As
     ctx.build()
 }
 
+// Assist: make_usual_string
+//
+// Turns a raw string into a plain string.
+//
+// ```
+// fn main() {
+//     r#"Hello,<|> "World!""#;
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     "Hello, \"World!\"";
+// }
+// ```
 pub(crate) fn make_usual_string(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
     let token = ctx.find_token_at_offset(RAW_STRING)?;
     let text = token.text().as_str();
@@ -56,6 +84,21 @@ pub(crate) fn make_usual_string(mut ctx: AssistCtx<impl HirDatabase>) -> Option<
     ctx.build()
 }
 
+// Assist: add_hash
+//
+// Adds a hash to a raw string literal.
+//
+// ```
+// fn main() {
+//     r#"Hello,<|> World!"#;
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     r##"Hello, World!"##;
+// }
+// ```
 pub(crate) fn add_hash(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
     let token = ctx.find_token_at_offset(RAW_STRING)?;
     ctx.add_action(AssistId("add_hash"), "add hash to raw string", |edit| {
@@ -66,6 +109,21 @@ pub(crate) fn add_hash(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
     ctx.build()
 }
 
+// Assist: remove_hash
+//
+// Removes a hash from a raw string literal.
+//
+// ```
+// fn main() {
+//     r#"Hello,<|> World!"#;
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     r"Hello, World!";
+// }
+// ```
 pub(crate) fn remove_hash(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
     let token = ctx.find_token_at_offset(RAW_STRING)?;
     let text = token.text().as_str();
diff --git a/crates/ra_assists/src/assists/remove_dbg.rs b/crates/ra_assists/src/assists/remove_dbg.rs
index ac2c43e1a..44b8de814 100644
--- a/crates/ra_assists/src/assists/remove_dbg.rs
+++ b/crates/ra_assists/src/assists/remove_dbg.rs
@@ -1,12 +1,26 @@
-//! FIXME: write short doc here
-
-use crate::{Assist, AssistCtx, AssistId};
 use hir::db::HirDatabase;
 use ra_syntax::{
     ast::{self, AstNode},
     TextUnit, T,
 };
 
+use crate::{Assist, AssistCtx, AssistId};
+
+// Assist: remove_dbg
+//
+// Removes `dbg!()` macro call.
+//
+// ```
+// fn main() {
+//     <|>dbg!(92);
+// }
+// ```
+// ->
+// ```
+// fn main() {
+//     92;
+// }
+// ```
 pub(crate) fn remove_dbg(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
     let macro_call = ctx.find_node_at_offset::<ast::MacroCall>()?;
 
diff --git a/crates/ra_assists/src/assists/replace_if_let_with_match.rs b/crates/ra_assists/src/assists/replace_if_let_with_match.rs
index da276e47b..58ef2ff20 100644
--- a/crates/ra_assists/src/assists/replace_if_let_with_match.rs
+++ b/crates/ra_assists/src/assists/replace_if_let_with_match.rs
@@ -1,5 +1,3 @@
-//! FIXME: write short doc here
-
 use format_buf::format;
 use hir::db::HirDatabase;
 use ra_fmt::extract_trivial_expression;
@@ -7,6 +5,32 @@ use ra_syntax::{ast, AstNode};
 
 use crate::{Assist, AssistCtx, AssistId};
 
+// Assist: replace_if_let_with_match
+//
+// Replaces `if let` with an else branch with a `match` expression.
+//
+// ```
+// enum Action { Move { distance: u32 }, Stop }
+//
+// fn handle(action: Action) {
+//     <|>if let Action::Move { distance } = action {
+//         foo(distance)
+//     } else {
+//         bar()
+//     }
+// }
+// ```
+// ->
+// ```
+// enum Action { Move { distance: u32 }, Stop }
+//
+// fn handle(action: Action) {
+//     match action {
+//         Action::Move { distance } => foo(distance),
+//         _ => bar(),
+//     }
+// }
+// ```
 pub(crate) fn replace_if_let_with_match(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
     let if_expr: ast::IfExpr = ctx.find_node_at_offset()?;
     let cond = if_expr.condition()?;
diff --git a/crates/ra_assists/src/assists/split_import.rs b/crates/ra_assists/src/assists/split_import.rs
index 09bde1b72..8d8a28987 100644
--- a/crates/ra_assists/src/assists/split_import.rs
+++ b/crates/ra_assists/src/assists/split_import.rs
@@ -1,5 +1,3 @@
-//! FIXME: write short doc here
-
 use std::iter::successors;
 
 use hir::db::HirDatabase;
@@ -7,6 +5,17 @@ use ra_syntax::{ast, AstNode, TextUnit, T};
 
 use crate::{Assist, AssistCtx, AssistId};
 
+// Assist: split_import
+//
+// Wraps the tail of import into braces.
+//
+// ```
+// use std::<|>collections::HashMap;
+// ```
+// ->
+// ```
+// use std::{collections::HashMap};
+// ```
 pub(crate) fn split_import(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
     let colon_colon = ctx.find_token_at_offset(T![::])?;
     let path = ast::Path::cast(colon_colon.parent())?;
diff --git a/crates/ra_assists/src/doc_tests/generated.rs b/crates/ra_assists/src/doc_tests/generated.rs
index 09677af68..b8d335911 100644
--- a/crates/ra_assists/src/doc_tests/generated.rs
+++ b/crates/ra_assists/src/doc_tests/generated.rs
@@ -40,6 +40,23 @@ fn main() {
 }
 
 #[test]
+fn doctest_add_hash() {
+    check(
+        "add_hash",
+        r#####"
+fn main() {
+    r#"Hello,<|> World!"#;
+}
+"#####,
+        r#####"
+fn main() {
+    r##"Hello, World!"##;
+}
+"#####,
+    )
+}
+
+#[test]
 fn doctest_add_impl() {
     check(
         "add_impl",
@@ -275,6 +292,40 @@ fn main() {
 }
 
 #[test]
+fn doctest_make_raw_string() {
+    check(
+        "make_raw_string",
+        r#####"
+fn main() {
+    "Hello,<|> World!";
+}
+"#####,
+        r#####"
+fn main() {
+    r#"Hello, World!"#;
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_make_usual_string() {
+    check(
+        "make_usual_string",
+        r#####"
+fn main() {
+    r#"Hello,<|> "World!""#;
+}
+"#####,
+        r#####"
+fn main() {
+    "Hello, \"World!\"";
+}
+"#####,
+    )
+}
+
+#[test]
 fn doctest_merge_match_arms() {
     check(
         "merge_match_arms",
@@ -370,3 +421,78 @@ fn handle(action: Action) {
 "#####,
     )
 }
+
+#[test]
+fn doctest_remove_dbg() {
+    check(
+        "remove_dbg",
+        r#####"
+fn main() {
+    <|>dbg!(92);
+}
+"#####,
+        r#####"
+fn main() {
+    92;
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_remove_hash() {
+    check(
+        "remove_hash",
+        r#####"
+fn main() {
+    r#"Hello,<|> World!"#;
+}
+"#####,
+        r#####"
+fn main() {
+    r"Hello, World!";
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_replace_if_let_with_match() {
+    check(
+        "replace_if_let_with_match",
+        r#####"
+enum Action { Move { distance: u32 }, Stop }
+
+fn handle(action: Action) {
+    <|>if let Action::Move { distance } = action {
+        foo(distance)
+    } else {
+        bar()
+    }
+}
+"#####,
+        r#####"
+enum Action { Move { distance: u32 }, Stop }
+
+fn handle(action: Action) {
+    match action {
+        Action::Move { distance } => foo(distance),
+        _ => bar(),
+    }
+}
+"#####,
+    )
+}
+
+#[test]
+fn doctest_split_import() {
+    check(
+        "split_import",
+        r#####"
+use std::<|>collections::HashMap;
+"#####,
+        r#####"
+use std::{collections::HashMap};
+"#####,
+    )
+}
diff --git a/docs/user/assists.md b/docs/user/assists.md
index 34a95696c..e4d08a7dc 100644
--- a/docs/user/assists.md
+++ b/docs/user/assists.md
@@ -38,6 +38,22 @@ fn main() {
 }
 ```
 
+## `add_hash`
+
+Adds a hash to a raw string literal.
+
+```rust
+// BEFORE
+fn main() {
+    r#"Hello,┃ World!"#;
+}
+
+// AFTER
+fn main() {
+    r##"Hello, World!"##;
+}
+```
+
 ## `add_impl`
 
 Adds a new inherent impl for a type.
@@ -266,6 +282,38 @@ fn main() {
 }
 ```
 
+## `make_raw_string`
+
+Adds `r#` to a plain string literal.
+
+```rust
+// BEFORE
+fn main() {
+    "Hello,┃ World!";
+}
+
+// AFTER
+fn main() {
+    r#"Hello, World!"#;
+}
+```
+
+## `make_usual_string`
+
+Turns a raw string into a plain string.
+
+```rust
+// BEFORE
+fn main() {
+    r#"Hello,┃ "World!""#;
+}
+
+// AFTER
+fn main() {
+    "Hello, \"World!\"";
+}
+```
+
 ## `merge_match_arms`
 
 Merges identical match arms.
@@ -358,3 +406,74 @@ fn handle(action: Action) {
     }
 }
 ```
+
+## `remove_dbg`
+
+Removes `dbg!()` macro call.
+
+```rust
+// BEFORE
+fn main() {
+    ┃dbg!(92);
+}
+
+// AFTER
+fn main() {
+    92;
+}
+```
+
+## `remove_hash`
+
+Removes a hash from a raw string literal.
+
+```rust
+// BEFORE
+fn main() {
+    r#"Hello,┃ World!"#;
+}
+
+// AFTER
+fn main() {
+    r"Hello, World!";
+}
+```
+
+## `replace_if_let_with_match`
+
+Replaces `if let` with an else branch with a `match` expression.
+
+```rust
+// BEFORE
+enum Action { Move { distance: u32 }, Stop }
+
+fn handle(action: Action) {
+    ┃if let Action::Move { distance } = action {
+        foo(distance)
+    } else {
+        bar()
+    }
+}
+
+// AFTER
+enum Action { Move { distance: u32 }, Stop }
+
+fn handle(action: Action) {
+    match action {
+        Action::Move { distance } => foo(distance),
+        _ => bar(),
+    }
+}
+```
+
+## `split_import`
+
+Wraps the tail of import into braces.
+
+```rust
+// BEFORE
+use std::┃collections::HashMap;
+
+// AFTER
+use std::{collections::HashMap};
+```
diff --git a/docs/user/features.md b/docs/user/features.md
index 2e213e34c..7ae2ca7b6 100644
--- a/docs/user/features.md
+++ b/docs/user/features.md
@@ -118,180 +118,6 @@ impl Debug<|> for Foo {
 }
 ```
 
-- Fill struct fields
-
-```rust
-// before:
-struct S<'a, D> {
-    a: u32,
-    b: String,
-    c: (i32, i32),
-    d: D,
-    r: &'a str,
-}
-
-fn main() {
-    let s = S<|> {}
-}
-
-// after:
-struct S<'a, D> {
-    a: u32,
-    b: String,
-    c: (i32, i32),
-    d: D,
-    r: &'a str,
-}
-
-fn main() {
-    let s = <|>S {
-        a: (),
-        b: (),
-        c: (),
-        d: (),
-        r: (),
-    }
-}
-```
-
-- Remove `dbg!`
-
-```rust
-// before:
-fn foo(n: usize) {
-    if let Some(_) = dbg!(n.<|>checked_sub(4)) {
-        // ...
-    }
-}
-
-// after:
-fn foo(n: usize) {
-    if let Some(_) = n.<|>checked_sub(4) {
-        // ...
-    }
-}
-```
-
-- Replace if-let with match:
-
-```rust
-// before:
-impl VariantData {
-    pub fn is_struct(&self) -> bool {
-        if <|>let VariantData::Struct(..) = *self {
-            true
-        } else {
-            false
-        }
-    }
-}
-
-// after:
-impl VariantData {
-    pub fn is_struct(&self) -> bool {
-        <|>match *self {
-            VariantData::Struct(..) => true,
-            _ => false,
-        }
-    }
-}
-```
-
-- Split import
-
-```rust
-// before:
-use crate:<|>:db::{RootDatabase, FileSymbol};
-// after:
-use crate::{<|>db::{RootDatabase, FileSymbol}};
-```
-
-- Move if condition to match arm guard
-```rust
-// before:
-fn f() {
-    let mut t = 'a';
-    let chars = "abcd";
-    match t {
-        '\r' => if chars.clone().next().is_some() {
-            t = 'e';<|>
-            false
-        },
-        _ => true
-    }
-}
-
-// after:
-fn f() {
-    let mut t = 'a';
-    let chars = "abcd";
-    match t {
-        '\r' <|>if chars.clone().next().is_some() => {
-            t = 'e';
-            false
-        },
-        _ => true
-    }
-}
-```
-
-- Make raw string unescaped
-
-```rust
-// before:
-fn f() {
-    let s = <|>"ab\ncd";
-}
-
-// after:
-fn f() {
-    let s = <|>r#"ab
-cd"#;
-}
-```
-
-- Make usual string
-
-```rust
-// before:
-fn f() {
-    let s = <|>r#"abcd"#;
-}
-
-// after:
-fn f() {
-    let s = <|>"abcd";
-}
-```
-
-- Add hash
-
-```rust
-// before:
-fn f() {
-    let s = <|>r"abcd";
-}
-
-// after:
-fn f() {
-    let s = <|>r#"abcd"#;
-}
-```
-
-- Remove hash
-
-```rust
-// before:
-fn f() {
-    let s = <|>r#"abcd"#;
-}
-
-// after:
-fn f() {
-    let s = <|>r"abcd";
-}
-```
-
 ### Magic Completions
 
 In addition to usual reference completion, rust-analyzer provides some ✨magic✨