Better semi colon adding management

Author: ThibsG

clippy_lints/src/matches.rs

@@ -833,46 +833,54 @@ fn check_match_single_binding(cx: &LateContext<'_, '_>, ex: &Expr<'_>, arms: &[A
     } else {
         snippet_block(cx, match_body.span, "..").to_owned().to_string()
     };
-    if let ExprKind::Block(block, _) = &arms[0].body.kind {
-        // Do we need to add ';' to suggestion ?
-        if block.stmts.len() == 1 {
-            if let StmtKind::Semi(_) = block.stmts.get(0).unwrap().kind {
-                if !snippet_body.starts_with('{') && !snippet_body.ends_with('}') {
-                    snippet_body.push(';');
+
+    // Do we need to add ';' to suggestion ?
+    if_chain! {
+        if let ExprKind::Block(block, _) = &arms[0].body.kind;
+        if block.stmts.len() == 1;
+        if let StmtKind::Semi(s) = block.stmts.get(0).unwrap().kind;
+        then {
+            match s.kind {
+                ExprKind::Block(_, _) => (),
+                _ => {
+                    // expr_ty(body) == ()
+                    if cx.tables.expr_ty(&arms[0].body).is_unit() {
+                        snippet_body.push(';');
+                    }
                 }
             }
         }
+    }
 
-        match arms[0].pat.kind {
-            PatKind::Binding(..) | PatKind::Tuple(_, _) | PatKind::Struct(..) => {
-                span_lint_and_sugg(
-                    cx,
-                    MATCH_SINGLE_BINDING,
-                    expr.span,
-                    "this match could be written as a `let` statement",
-                    "consider using `let` statement",
-                    format!(
-                        "let {} = {};\n{}",
-                        snippet(cx, bind_names, ".."),
-                        snippet(cx, matched_vars, ".."),
-                        snippet_body
-                    ),
-                    Applicability::MachineApplicable,
-                );
-            },
-            PatKind::Wild => {
-                span_lint_and_sugg(
-                    cx,
-                    MATCH_SINGLE_BINDING,
-                    expr.span,
-                    "this match could be replaced by its body itself",
-                    "consider using the match body instead",
-                    snippet_body,
-                    Applicability::MachineApplicable,
-                );
-            },
-            _ => (),
-        }
+    match arms[0].pat.kind {
+        PatKind::Binding(..) | PatKind::Tuple(_, _) | PatKind::Struct(..) => {
+            span_lint_and_sugg(
+                cx,
+                MATCH_SINGLE_BINDING,
+                expr.span,
+                "this match could be written as a `let` statement",
+                "consider using `let` statement",
+                format!(
+                    "let {} = {};\n{}",
+                    snippet(cx, bind_names, ".."),
+                    snippet(cx, matched_vars, ".."),
+                    snippet_body
+                ),
+                Applicability::MachineApplicable,
+            );
+        },
+        PatKind::Wild => {
+            span_lint_and_sugg(
+                cx,
+                MATCH_SINGLE_BINDING,
+                expr.span,
+                "this match could be replaced by its body itself",
+                "consider using the match body instead",
+                snippet_body,
+                Applicability::MachineApplicable,
+            );
+        },
+        _ => (),
     }
 }