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Support "move if to guard" for if else chains
| -rw-r--r-- | crates/ide_assists/src/handlers/move_guard.rs | 350 |
1 files changed, 292 insertions, 58 deletions
diff --git a/crates/ide_assists/src/handlers/move_guard.rs b/crates/ide_assists/src/handlers/move_guard.rs index 8a2c51d33b..58c37471e6 100644 --- a/crates/ide_assists/src/handlers/move_guard.rs +++ b/crates/ide_assists/src/handlers/move_guard.rs @@ -1,7 +1,8 @@ use syntax::{ - ast::{edit::AstNodeEdit, make, AstNode, BlockExpr, ElseBranch, Expr, IfExpr, MatchArm}, - NodeOrToken, - SyntaxKind::{COMMA, WHITESPACE}, + ast::{ + edit::AstNodeEdit, make, AstNode, BlockExpr, Condition, ElseBranch, Expr, IfExpr, MatchArm, + }, + SyntaxKind::WHITESPACE, }; use crate::{AssistContext, AssistId, AssistKind, Assists}; @@ -115,73 +116,119 @@ pub(crate) fn move_arm_cond_to_match_guard(acc: &mut Assists, ctx: &AssistContex } })?; let replace_node = replace_node.unwrap_or_else(|| if_expr.syntax().clone()); - - let cond = if_expr.condition()?; - let then_block = if_expr.then_branch()?; - - // Not support moving if let to arm guard - if cond.is_pattern_cond() { - return None; - } - - let buf = format!(" if {}", cond.syntax().text()); - + // Dedent if if_expr is in a BlockExpr + let dedent = if replace_node != *if_expr.syntax() { + cov_mark::hit!(move_guard_ifelse_in_block); + 1 + } else { + cov_mark::hit!(move_guard_ifelse_else_block); + 0 + }; + + let (conds_blocks, tail) = parse_if_chain(if_expr)?; + + let then_arm_end = match_arm.syntax().text_range().end(); + let indent_level = match_arm.indent_level(); + let spaces = " ".repeat(indent_level.0 as _); acc.add( AssistId("move_arm_cond_to_match_guard", AssistKind::RefactorRewrite), "Move condition to match guard", replace_node.text_range(), |edit| { - let then_only_expr = then_block.statements().next().is_none(); - - match &then_block.tail_expr() { - Some(then_expr) if then_only_expr => { - edit.replace(replace_node.text_range(), then_expr.syntax().text()); - // Insert comma for expression if there isn't one - match match_arm.syntax().last_child_or_token() { - Some(NodeOrToken::Token(t)) if t.kind() == COMMA => {} - _ => { - cov_mark::hit!(move_guard_if_add_comma); - edit.insert(match_arm.syntax().text_range().end(), ","); - } - } + edit.delete(match_arm.syntax().text_range()); + let mut first = true; + for (cond, block) in conds_blocks { + if !first { + edit.insert(then_arm_end, format!("\n{}", spaces)); + } else { + first = false; } - _ if replace_node != *if_expr.syntax() => { - // Dedent because if_expr is in a BlockExpr - let replace_with = then_block.dedent(1.into()).syntax().text(); - edit.replace(replace_node.text_range(), replace_with) - } - _ => edit.replace(replace_node.text_range(), then_block.syntax().text()), - } - - edit.insert(match_pat.syntax().text_range().end(), buf); - - // If with only an else branch - if let Some(ElseBranch::Block(else_block)) = if_expr.else_branch() { - let then_arm_end = match_arm.syntax().text_range().end(); - let else_only_expr = else_block.statements().next().is_none(); - let indent_level = match_arm.indent_level(); - let spaces = " ".repeat(indent_level.0 as _); - edit.insert(then_arm_end, format!("\n{}{} => ", spaces, match_pat)); - match &else_block.tail_expr() { - Some(else_expr) if else_only_expr => { - cov_mark::hit!(move_guard_ifelse_expr_only); - edit.insert(then_arm_end, else_expr.syntax().text()); + let guard = format!("{} if {} => ", match_pat, cond.syntax().text()); + edit.insert(then_arm_end, guard); + let only_expr = block.statements().next().is_none(); + match &block.tail_expr() { + Some(then_expr) if only_expr => { + edit.insert(then_arm_end, then_expr.syntax().text()); edit.insert(then_arm_end, ","); } - _ if replace_node != *if_expr.syntax() => { - cov_mark::hit!(move_guard_ifelse_in_block); - edit.insert(then_arm_end, else_block.dedent(1.into()).syntax().text()); - } _ => { - cov_mark::hit!(move_guard_ifelse_else_block); - edit.insert(then_arm_end, else_block.syntax().text()); + let to_insert = block.dedent(dedent.into()).syntax().text(); + edit.insert(then_arm_end, to_insert) + } + } + } + match tail { + Some(Tail::IfLet(e)) => { + cov_mark::hit!(move_guard_ifelse_iflet_tail); + let guard = format!("\n{}{} => ", spaces, match_pat); + // Put the if-let expression in a block + let iflet_expr: Expr = e.reset_indent().indent(1.into()).into(); + let iflet_block = + make::block_expr(std::iter::empty(), Some(iflet_expr)).indent(indent_level); + edit.insert(then_arm_end, guard); + edit.insert(then_arm_end, iflet_block.syntax().text()); + } + Some(Tail::Else(e)) => { + cov_mark::hit!(move_guard_ifelse_else_tail); + let guard = format!("\n{}{} => ", spaces, match_pat); + edit.insert(then_arm_end, guard); + let only_expr = e.statements().next().is_none(); + match &e.tail_expr() { + Some(expr) if only_expr => { + cov_mark::hit!(move_guard_ifelse_expr_only); + edit.insert(then_arm_end, expr.syntax().text()); + edit.insert(then_arm_end, ","); + } + _ => { + let to_insert = e.dedent(dedent.into()).syntax().text(); + edit.insert(then_arm_end, to_insert) + } } } + _ => { + cov_mark::hit!(move_guard_ifelse_notail); + } } }, ) } +#[derive(Debug)] +enum Tail { + Else(BlockExpr), + IfLet(IfExpr), +} + +// Parses an if-else-if chain to get the conditons and the then branches until we encounter an else +// branch, an if-let branch or the end. +fn parse_if_chain(if_expr: IfExpr) -> Option<(Vec<(Condition, BlockExpr)>, Option<Tail>)> { + let mut conds_blocks = Vec::new(); + let mut curr_if = if_expr; + let mut applicable = false; + let tail: Option<Tail> = loop { + let cond = curr_if.condition()?; + if cond.is_pattern_cond() { + break Some(Tail::IfLet(curr_if)); + } + conds_blocks.push((cond, curr_if.then_branch()?)); + applicable = true; + match curr_if.else_branch() { + Some(ElseBranch::IfExpr(e)) => { + curr_if = e; + } + Some(ElseBranch::Block(b)) => { + break Some(Tail::Else(b)); + } + None => break None, + } + }; + if !applicable { + // The first if branch is an if-let branch + return None; + } + Some((conds_blocks, tail)) +} + #[cfg(test)] mod tests { use super::*; @@ -321,7 +368,6 @@ fn main() { #[test] fn move_arm_cond_in_block_to_match_guard_add_comma_works() { - cov_mark::check!(move_guard_if_add_comma); check_assist( move_arm_cond_to_match_guard, r#" @@ -377,7 +423,7 @@ fn main() { r#" fn main() { match 92 { - x if x > 10 => { }, + x if x > 10 => { } _ => true } } @@ -406,7 +452,7 @@ fn main() { x if x > 10 => { 92; false - }, + } _ => true } } @@ -519,7 +565,7 @@ fn main() { r#" fn main() { match 92 { - x if x > 10 => { }, + x if x > 10 => { } x => { } _ => true } @@ -693,4 +739,192 @@ fn main() { "#, ) } + + #[test] + fn move_arm_cond_to_match_guard_elseif() { + check_assist( + move_arm_cond_to_match_guard, + r#" +fn main() { + match 92 { + 3 => true, + x => if x > 10 {$0 + false + } else if x > 5 { + true + } else if x > 4 { + false + } else { + true + }, + } +} +"#, + r#" +fn main() { + match 92 { + 3 => true, + x if x > 10 => false, + x if x > 5 => true, + x if x > 4 => false, + x => true, + } +} +"#, + ) + } + + #[test] + fn move_arm_cond_to_match_guard_elseif_in_block() { + cov_mark::check!(move_guard_ifelse_in_block); + check_assist( + move_arm_cond_to_match_guard, + r#" +fn main() { + match 92 { + 3 => true, + x => { + if x > 10 {$0 + false + } else if x > 5 { + true + } else if x > 4 { + false + } else { + true + } + } + } +} +"#, + r#" +fn main() { + match 92 { + 3 => true, + x if x > 10 => false, + x if x > 5 => true, + x if x > 4 => false, + x => true, + } +} +"#, + ) + } + + #[test] + fn move_arm_cond_to_match_guard_elseif_chain() { + cov_mark::check!(move_guard_ifelse_else_tail); + check_assist( + move_arm_cond_to_match_guard, + r#" +fn main() { + match 92 { + 3 => 0, + x => if x > 10 {$0 + 1 + } else if x > 5 { + 2 + } else if x > 3 { + 42; + 3 + } else { + 4 + }, + } +} +"#, + r#" +fn main() { + match 92 { + 3 => 0, + x if x > 10 => 1, + x if x > 5 => 2, + x if x > 3 => { + 42; + 3 + } + x => 4, + } +} +"#, + ) + } + + #[test] + fn move_arm_cond_to_match_guard_elseif_iflet() { + cov_mark::check!(move_guard_ifelse_iflet_tail); + check_assist( + move_arm_cond_to_match_guard, + r#" +fn main() { + match 92 { + 3 => 0, + x => if x > 10 {$0 + 1 + } else if x > 5 { + 2 + } else if let 4 = 4 { + 42; + 3 + } else { + 4 + }, + } +} +"#, + r#" +fn main() { + match 92 { + 3 => 0, + x if x > 10 => 1, + x if x > 5 => 2, + x => { + if let 4 = 4 { + 42; + 3 + } else { + 4 + } + } + } +} +"#, + ) + } + + #[test] + fn move_arm_cond_to_match_guard_elseif_notail() { + cov_mark::check!(move_guard_ifelse_notail); + check_assist( + move_arm_cond_to_match_guard, + r#" +fn main() { + match 92 { + 3 => 0, + x => if x > 10 {$0 + 1 + } else if x > 5 { + 2 + } else if x > 4 { + 42; + 3 + }, + } +} +"#, + r#" +fn main() { + match 92 { + 3 => 0, + x if x > 10 => 1, + x if x > 5 => 2, + x if x > 4 => { + 42; + 3 + } + } +} +"#, + ) + } } |