1 files changed, 512 insertions, 0 deletions

diff --git a/crates/ra_assists/src/handlers/unwrap_block.rs b/crates/ra_assists/src/handlers/unwrap_block.rs
new file mode 100644
index 000000000..8440c7d0f
--- /dev/null
+++ b/crates/ra_assists/src/handlers/unwrap_block.rs
@@ -0,0 +1,512 @@
+use ra_fmt::unwrap_trivial_block;
+use ra_syntax::{
+    ast::{self, ElseBranch, Expr, LoopBodyOwner},
+    match_ast, AstNode, TextRange, T,
+};
+
+use crate::{AssistContext, AssistId, Assists};
+
+// Assist: unwrap_block
+//
+// This assist removes if...else, for, while and loop control statements to just keep the body.
+//
+// ```
+// fn foo() {
+//     if true {<|>
+//         println!("foo");
+//     }
+// }
+// ```
+// ->
+// ```
+// fn foo() {
+//     println!("foo");
+// }
+// ```
+pub(crate) fn unwrap_block(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let l_curly_token = ctx.find_token_at_offset(T!['{'])?;
+    let block = ast::BlockExpr::cast(l_curly_token.parent())?;
+    let parent = block.syntax().parent()?;
+    let assist_id = AssistId("unwrap_block");
+    let assist_label = "Unwrap block";
+
+    let (expr, expr_to_unwrap) = match_ast! {
+        match parent {
+            ast::ForExpr(for_expr) => {
+                let block_expr = for_expr.loop_body()?;
+                let expr_to_unwrap = extract_expr(ctx.frange.range, block_expr)?;
+                (ast::Expr::ForExpr(for_expr), expr_to_unwrap)
+            },
+            ast::WhileExpr(while_expr) => {
+                let block_expr = while_expr.loop_body()?;
+                let expr_to_unwrap = extract_expr(ctx.frange.range, block_expr)?;
+                (ast::Expr::WhileExpr(while_expr), expr_to_unwrap)
+            },
+            ast::LoopExpr(loop_expr) => {
+                let block_expr = loop_expr.loop_body()?;
+                let expr_to_unwrap = extract_expr(ctx.frange.range, block_expr)?;
+                (ast::Expr::LoopExpr(loop_expr), expr_to_unwrap)
+            },
+            ast::IfExpr(if_expr) => {
+                let mut resp = None;
+
+                let then_branch = if_expr.then_branch()?;
+                if then_branch.l_curly_token()?.text_range().contains_range(ctx.frange.range) {
+                    if let Some(ancestor) = if_expr.syntax().parent().and_then(ast::IfExpr::cast) {
+                        // For `else if` blocks
+                        let ancestor_then_branch = ancestor.then_branch()?;
+                        let l_curly_token = then_branch.l_curly_token()?;
+
+                        let target = then_branch.syntax().text_range();
+                        return acc.add(assist_id, assist_label, target, |edit| {
+                            let range_to_del_else_if = TextRange::new(ancestor_then_branch.syntax().text_range().end(), l_curly_token.text_range().start());
+                            let range_to_del_rest = TextRange::new(then_branch.syntax().text_range().end(), if_expr.syntax().text_range().end());
+
+                            edit.delete(range_to_del_rest);
+                            edit.delete(range_to_del_else_if);
+                            edit.replace(target, update_expr_string(then_branch.to_string(), &[' ', '{']));
+                        });
+                    } else {
+                        resp = Some((ast::Expr::IfExpr(if_expr.clone()), Expr::BlockExpr(then_branch)));
+                    }
+                } else if let Some(else_branch) = if_expr.else_branch() {
+                    match else_branch {
+                        ElseBranch::Block(else_block) => {
+                            let l_curly_token = else_block.l_curly_token()?;
+                            if l_curly_token.text_range().contains_range(ctx.frange.range) {
+                                let target = else_block.syntax().text_range();
+                                return acc.add(assist_id, assist_label, target, |edit| {
+                                    let range_to_del = TextRange::new(then_branch.syntax().text_range().end(), l_curly_token.text_range().start());
+
+                                    edit.delete(range_to_del);
+                                    edit.replace(target, update_expr_string(else_block.to_string(), &[' ', '{']));
+                                });
+                            }
+                        },
+                        ElseBranch::IfExpr(_) => {},
+                    }
+                }
+
+                resp?
+            },
+            _ => return None,
+        }
+    };
+
+    let target = expr_to_unwrap.syntax().text_range();
+    acc.add(assist_id, assist_label, target, |edit| {
+        edit.replace(
+            expr.syntax().text_range(),
+            update_expr_string(expr_to_unwrap.to_string(), &[' ', '{', '\n']),
+        );
+    })
+}
+
+fn extract_expr(cursor_range: TextRange, block: ast::BlockExpr) -> Option<ast::Expr> {
+    let cursor_in_range = block.l_curly_token()?.text_range().contains_range(cursor_range);
+
+    if cursor_in_range {
+        Some(unwrap_trivial_block(block))
+    } else {
+        None
+    }
+}
+
+fn update_expr_string(expr_str: String, trim_start_pat: &[char]) -> String {
+    let expr_string = expr_str.trim_start_matches(trim_start_pat);
+    let mut expr_string_lines: Vec<&str> = expr_string.lines().collect();
+    expr_string_lines.pop(); // Delete last line
+
+    expr_string_lines
+        .into_iter()
+        .map(|line| line.replacen("    ", "", 1)) // Delete indentation
+        .collect::<Vec<String>>()
+        .join("\n")
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    #[test]
+    fn simple_if() {
+        check_assist(
+            unwrap_block,
+            r#"
+            fn main() {
+                bar();
+                if true {<|>
+                    foo();
+
+                    //comment
+                    bar();
+                } else {
+                    println!("bar");
+                }
+            }
+            "#,
+            r#"
+            fn main() {
+                bar();
+                foo();
+
+                //comment
+                bar();
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn simple_if_else() {
+        check_assist(
+            unwrap_block,
+            r#"
+            fn main() {
+                bar();
+                if true {
+                    foo();
+
+                    //comment
+                    bar();
+                } else {<|>
+                    println!("bar");
+                }
+            }
+            "#,
+            r#"
+            fn main() {
+                bar();
+                if true {
+                    foo();
+
+                    //comment
+                    bar();
+                }
+                println!("bar");
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn simple_if_else_if() {
+        check_assist(
+            unwrap_block,
+            r#"
+            fn main() {
+                //bar();
+                if true {
+                    println!("true");
+
+                    //comment
+                    //bar();
+                } else if false {<|>
+                    println!("bar");
+                } else {
+                    println!("foo");
+                }
+            }
+            "#,
+            r#"
+            fn main() {
+                //bar();
+                if true {
+                    println!("true");
+
+                    //comment
+                    //bar();
+                }
+                println!("bar");
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn simple_if_else_if_nested() {
+        check_assist(
+            unwrap_block,
+            r#"
+            fn main() {
+                //bar();
+                if true {
+                    println!("true");
+
+                    //comment
+                    //bar();
+                } else if false {
+                    println!("bar");
+                } else if true {<|>
+                    println!("foo");
+                }
+            }
+            "#,
+            r#"
+            fn main() {
+                //bar();
+                if true {
+                    println!("true");
+
+                    //comment
+                    //bar();
+                } else if false {
+                    println!("bar");
+                }
+                println!("foo");
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn simple_if_else_if_nested_else() {
+        check_assist(
+            unwrap_block,
+            r#"
+            fn main() {
+                //bar();
+                if true {
+                    println!("true");
+
+                    //comment
+                    //bar();
+                } else if false {
+                    println!("bar");
+                } else if true {
+                    println!("foo");
+                } else {<|>
+                    println!("else");
+                }
+            }
+            "#,
+            r#"
+            fn main() {
+                //bar();
+                if true {
+                    println!("true");
+
+                    //comment
+                    //bar();
+                } else if false {
+                    println!("bar");
+                } else if true {
+                    println!("foo");
+                }
+                println!("else");
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn simple_if_else_if_nested_middle() {
+        check_assist(
+            unwrap_block,
+            r#"
+            fn main() {
+                //bar();
+                if true {
+                    println!("true");
+
+                    //comment
+                    //bar();
+                } else if false {
+                    println!("bar");
+                } else if true {<|>
+                    println!("foo");
+                } else {
+                    println!("else");
+                }
+            }
+            "#,
+            r#"
+            fn main() {
+                //bar();
+                if true {
+                    println!("true");
+
+                    //comment
+                    //bar();
+                } else if false {
+                    println!("bar");
+                }
+                println!("foo");
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn simple_if_bad_cursor_position() {
+        check_assist_not_applicable(
+            unwrap_block,
+            r#"
+            fn main() {
+                bar();<|>
+                if true {
+                    foo();
+
+                    //comment
+                    bar();
+                } else {
+                    println!("bar");
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn simple_for() {
+        check_assist(
+            unwrap_block,
+            r#"
+            fn main() {
+                for i in 0..5 {<|>
+                    if true {
+                        foo();
+
+                        //comment
+                        bar();
+                    } else {
+                        println!("bar");
+                    }
+                }
+            }
+            "#,
+            r#"
+            fn main() {
+                if true {
+                    foo();
+
+                    //comment
+                    bar();
+                } else {
+                    println!("bar");
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn simple_if_in_for() {
+        check_assist(
+            unwrap_block,
+            r#"
+            fn main() {
+                for i in 0..5 {
+                    if true {<|>
+                        foo();
+
+                        //comment
+                        bar();
+                    } else {
+                        println!("bar");
+                    }
+                }
+            }
+            "#,
+            r#"
+            fn main() {
+                for i in 0..5 {
+                    foo();
+
+                    //comment
+                    bar();
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn simple_loop() {
+        check_assist(
+            unwrap_block,
+            r#"
+            fn main() {
+                loop {<|>
+                    if true {
+                        foo();
+
+                        //comment
+                        bar();
+                    } else {
+                        println!("bar");
+                    }
+                }
+            }
+            "#,
+            r#"
+            fn main() {
+                if true {
+                    foo();
+
+                    //comment
+                    bar();
+                } else {
+                    println!("bar");
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn simple_while() {
+        check_assist(
+            unwrap_block,
+            r#"
+            fn main() {
+                while true {<|>
+                    if true {
+                        foo();
+
+                        //comment
+                        bar();
+                    } else {
+                        println!("bar");
+                    }
+                }
+            }
+            "#,
+            r#"
+            fn main() {
+                if true {
+                    foo();
+
+                    //comment
+                    bar();
+                } else {
+                    println!("bar");
+                }
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn simple_if_in_while_bad_cursor_position() {
+        check_assist_not_applicable(
+            unwrap_block,
+            r#"
+            fn main() {
+                while true {
+                    if true {
+                        foo();<|>
+
+                        //comment
+                        bar();
+                    } else {
+                        println!("bar");
+                    }
+                }
+            }
+            "#,
+        );
+    }
+}