diff --git a/crates/hir-ty/src/diagnostics/expr.rs b/crates/hir-ty/src/diagnostics/expr.rs index 0c5d6399619..6c8a1875165 100644 --- a/crates/hir-ty/src/diagnostics/expr.rs +++ b/crates/hir-ty/src/diagnostics/expr.rs @@ -12,6 +12,7 @@ use itertools::Itertools; use rustc_hash::FxHashSet; use rustc_pattern_analysis::usefulness::{compute_match_usefulness, ValidityConstraint}; +use syntax::{ast, AstNode}; use tracing::debug; use triomphe::Arc; use typed_arena::Arena; @@ -108,7 +109,7 @@ fn validate_body(&mut self, db: &dyn HirDatabase) { self.check_for_trailing_return(*body_expr, &body); } Expr::If { .. } => { - self.check_for_unnecessary_else(id, expr, &body); + self.check_for_unnecessary_else(id, expr, db); } Expr::Block { .. } => { self.validate_block(db, expr); @@ -336,12 +337,12 @@ fn check_for_trailing_return(&mut self, body_expr: ExprId, body: &Body) { } } - fn check_for_unnecessary_else(&mut self, id: ExprId, expr: &Expr, body: &Body) { + fn check_for_unnecessary_else(&mut self, id: ExprId, expr: &Expr, db: &dyn HirDatabase) { if let Expr::If { condition: _, then_branch, else_branch } = expr { if else_branch.is_none() { return; } - if let Expr::Block { statements, tail, .. } = &body.exprs[*then_branch] { + if let Expr::Block { statements, tail, .. } = &self.body.exprs[*then_branch] { let last_then_expr = tail.or_else(|| match statements.last()? { Statement::Expr { expr, .. } => Some(*expr), _ => None, @@ -349,6 +350,36 @@ fn check_for_unnecessary_else(&mut self, id: ExprId, expr: &Expr, body: &Body) { if let Some(last_then_expr) = last_then_expr { let last_then_expr_ty = &self.infer[last_then_expr]; if last_then_expr_ty.is_never() { + // Only look at sources if the then branch diverges and we have an else branch. + let (_, source_map) = db.body_with_source_map(self.owner); + let Ok(source_ptr) = source_map.expr_syntax(id) else { + return; + }; + let root = source_ptr.file_syntax(db.upcast()); + let ast::Expr::IfExpr(if_expr) = source_ptr.value.to_node(&root) else { + return; + }; + let mut top_if_expr = if_expr; + loop { + let parent = top_if_expr.syntax().parent(); + let has_parent_expr_stmt_or_stmt_list = + parent.as_ref().map_or(false, |node| { + ast::ExprStmt::can_cast(node.kind()) + | ast::StmtList::can_cast(node.kind()) + }); + if has_parent_expr_stmt_or_stmt_list { + // Only emit diagnostic if parent or direct ancestor is either + // an expr stmt or a stmt list. + break; + } + let Some(parent_if_expr) = parent.and_then(ast::IfExpr::cast) else { + // Bail if parent is neither an if expr, an expr stmt nor a stmt list. + return; + }; + // Check parent if expr. + top_if_expr = parent_if_expr; + } + self.diagnostics .push(BodyValidationDiagnostic::RemoveUnnecessaryElse { if_expr: id }) } diff --git a/crates/ide-diagnostics/src/handlers/remove_unnecessary_else.rs b/crates/ide-diagnostics/src/handlers/remove_unnecessary_else.rs index ae8241ec2c6..9c63d79d910 100644 --- a/crates/ide-diagnostics/src/handlers/remove_unnecessary_else.rs +++ b/crates/ide-diagnostics/src/handlers/remove_unnecessary_else.rs @@ -2,7 +2,10 @@ use ide_db::{assists::Assist, source_change::SourceChange}; use itertools::Itertools; use syntax::{ - ast::{self, edit::IndentLevel}, + ast::{ + self, + edit::{AstNodeEdit, IndentLevel}, + }, AstNode, SyntaxToken, TextRange, }; use text_edit::TextEdit; @@ -41,10 +44,15 @@ fn fixes(ctx: &DiagnosticsContext<'_>, d: &RemoveUnnecessaryElse) -> Option { - block.statements().map(|stmt| format!("\n{indent}{stmt}")).join("") - } - ast::ElseBranch::IfExpr(ref nested_if_expr) => { + ast::ElseBranch::Block(block) => block + .statements() + .map(|stmt| format!("\n{indent}{stmt}")) + .chain(block.tail_expr().map(|tail| format!("\n{indent}{tail}"))) + .join(""), + ast::ElseBranch::IfExpr(mut nested_if_expr) => { + if has_parent_if_expr { + nested_if_expr = nested_if_expr.indent(IndentLevel(1)) + } format!("\n{indent}{nested_if_expr}") } }; @@ -171,6 +179,41 @@ fn test() { ); } + #[test] + fn remove_unnecessary_else_for_return3() { + check_diagnostics_with_needless_return_disabled( + r#" +fn test(a: bool) -> i32 { + if a { + return 1; + } else { + //^^^^ 💡 weak: remove unnecessary else block + 0 + } +} +"#, + ); + check_fix( + r#" +fn test(a: bool) -> i32 { + if a { + return 1; + } else$0 { + 0 + } +} +"#, + r#" +fn test(a: bool) -> i32 { + if a { + return 1; + } + 0 +} +"#, + ); + } + #[test] fn remove_unnecessary_else_for_return_in_child_if_expr() { check_diagnostics_with_needless_return_disabled( @@ -214,6 +257,41 @@ fn test() { ); } + #[test] + fn remove_unnecessary_else_for_return_in_child_if_expr2() { + check_fix( + r#" +fn test() { + if foo { + do_something(); + } else if qux { + return bar; + } else$0 if quux { + do_something_else(); + } else { + do_something_else2(); + } +} +"#, + r#" +fn test() { + if foo { + do_something(); + } else { + if qux { + return bar; + } + if quux { + do_something_else(); + } else { + do_something_else2(); + } + } +} +"#, + ); + } + #[test] fn remove_unnecessary_else_for_break() { check_diagnostics( @@ -384,6 +462,40 @@ fn test() { return bar; } } +"#, + ); + } + + #[test] + fn no_diagnostic_if_not_expr_stmt() { + check_diagnostics_with_needless_return_disabled( + r#" +fn test1() { + let _x = if a { + return; + } else { + 1 + }; +} + +fn test2() { + let _x = if a { + return; + } else if b { + return; + } else if c { + 1 + } else { + return; + }; +} +"#, + ); + check_diagnostics( + r#" +fn test3() -> u8 { + foo(if a { return 1 } else { 0 }) +} "#, ); }