bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/hir-ty/src/diagnostics/expr.rs')
-rw-r--r--crates/hir-ty/src/diagnostics/expr.rs29
1 files changed, 28 insertions, 1 deletions
diff --git a/crates/hir-ty/src/diagnostics/expr.rs b/crates/hir-ty/src/diagnostics/expr.rs
index 52e635a26e..c09351390a 100644
--- a/crates/hir-ty/src/diagnostics/expr.rs
+++ b/crates/hir-ty/src/diagnostics/expr.rs
@@ -27,7 +27,7 @@ use crate::{
pub(crate) use hir_def::{
body::Body,
- hir::{Expr, ExprId, MatchArm, Pat, PatId},
+ hir::{Expr, ExprId, MatchArm, Pat, PatId, Statement},
LocalFieldId, VariantId,
};
@@ -44,6 +44,9 @@ pub enum BodyValidationDiagnostic {
match_expr: ExprId,
uncovered_patterns: String,
},
+ RemoveUnnecessaryElse {
+ if_expr: ExprId,
+ },
}
impl BodyValidationDiagnostic {
@@ -90,6 +93,9 @@ impl ExprValidator {
Expr::Call { .. } | Expr::MethodCall { .. } => {
self.validate_call(db, id, expr, &mut filter_map_next_checker);
}
+ Expr::If { .. } => {
+ self.check_for_unnecessary_else(id, expr, &body);
+ }
_ => {}
}
}
@@ -237,6 +243,27 @@ impl ExprValidator {
}
pattern
}
+
+ fn check_for_unnecessary_else(&mut self, id: ExprId, expr: &Expr, body: &Body) {
+ 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] {
+ let last_then_expr = tail.or_else(|| match statements.last()? {
+ Statement::Expr { expr, .. } => Some(*expr),
+ _ => None,
+ });
+ 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() {
+ self.diagnostics
+ .push(BodyValidationDiagnostic::RemoveUnnecessaryElse { if_expr: id })
+ }
+ }
+ }
+ }
+ }
}
struct FilterMapNextChecker {