needless_return: Support #[expect] on the return statement

xFrednet · Jul 1, 2024 · 6eb6cfb · 6eb6cfb
1 parent f24a870
commit 6eb6cfb
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Showing 4 changed files with 46 additions and 22 deletions.
diff --git a/clippy_lints/src/returns.rs b/clippy_lints/src/returns.rs
@@ -14,7 +14,7 @@ use rustc_hir::{
     Block, Body, Expr, ExprKind, FnDecl, HirId, ItemKind, LangItem, MatchSource, Node, OwnerNode, PatKind, QPath, Stmt,
     StmtKind,
 };
-use rustc_lint::{LateContext, LateLintPass, LintContext};
+use rustc_lint::{LateContext, LateLintPass, Level, LintContext};
 use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::adjustment::Adjust;
 use rustc_middle::ty::{self, GenericArgKind, Ty};
@@ -377,13 +377,27 @@ fn check_final_expr<'tcx>(
                 }
             };
 
-            if !cx.tcx.hir().attrs(expr.hir_id).is_empty() {
-                return;
-            }
             let borrows = inner.map_or(false, |inner| last_statement_borrows(cx, inner));
             if borrows {
                 return;
             }
+            if ret_span.from_expansion() {
+                return;
+            }
+
+            // Returns may be used to turn an expression into a statement in rustc's AST.
+            // This allows the addition of attributes, like `#[allow]` (See: clippy#9361)
+            // However, this interacts very weirdly with `#[expect(clippy::needless_return)]`
+            // as adding that attribute will suppress the lint and then not fulfill the
+            // expectation. We'll therefore just manually mark the expectation.
+            match cx.tcx.lint_level_at_node(NEEDLESS_RETURN, expr.hir_id).0 {
+                Level::Allow => return,
+                Level::Expect(expectation) | Level::ForceWarn(Some(expectation)) => cx.fulfill_expectation(expectation),
+                _ => {},
+            }
+            if !cx.tcx.hir().attrs(expr.hir_id).is_empty() {
+                return;
+            }
 
             emit_return_lint(cx, ret_span, semi_spans, &replacement, expr.hir_id);
         },
@@ -415,10 +429,6 @@ fn emit_return_lint(
     replacement: &RetReplacement<'_>,
     at: HirId,
 ) {
-    if ret_span.from_expansion() {
-        return;
-    }
-
     span_lint_hir_and_then(
         cx,
         NEEDLESS_RETURN,

diff --git a/tests/ui/needless_return.fixed b/tests/ui/needless_return.fixed
@@ -234,6 +234,13 @@ fn issue_9361() -> i32 {
     return n + n;
 }
 
+fn issue_12998() -> i32 {
+    let x = 1;
+
+    #[expect(clippy::needless_return)]
+    return x;
+}
+
 fn issue8336(x: i32) -> bool {
     if x > 0 {
         println!("something");

diff --git a/tests/ui/needless_return.rs b/tests/ui/needless_return.rs
@@ -242,6 +242,13 @@ fn issue_9361() -> i32 {
     return n + n;
 }
 
+fn issue_12998() -> i32 {
+    let x = 1;
+
+    #[expect(clippy::needless_return)]
+    return x;
+}
+
 fn issue8336(x: i32) -> bool {
     if x > 0 {
         println!("something");

diff --git a/tests/ui/needless_return.stderr b/tests/ui/needless_return.stderr
@@ -483,7 +483,7 @@ LL +     format!("Hello {}", "world!")
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:248:9
+  --> tests/ui/needless_return.rs:255:9
    |
 LL |         return true;
    |         ^^^^^^^^^^^
@@ -497,7 +497,7 @@ LL ~     }
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:250:9
+  --> tests/ui/needless_return.rs:257:9
    |
 LL |         return false;
    |         ^^^^^^^^^^^^
@@ -509,7 +509,7 @@ LL ~     }
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:257:13
+  --> tests/ui/needless_return.rs:264:13
    |
 LL |             return 10;
    |             ^^^^^^^^^
@@ -524,7 +524,7 @@ LL ~     }
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:260:13
+  --> tests/ui/needless_return.rs:267:13
    |
 LL |             return 100;
    |             ^^^^^^^^^^
@@ -537,7 +537,7 @@ LL ~     }
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:268:9
+  --> tests/ui/needless_return.rs:275:9
    |
 LL |         return 0;
    |         ^^^^^^^^
@@ -549,7 +549,7 @@ LL ~     }
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:275:13
+  --> tests/ui/needless_return.rs:282:13
    |
 LL |             return *(x as *const isize);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -564,7 +564,7 @@ LL ~     }
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:277:13
+  --> tests/ui/needless_return.rs:284:13
    |
 LL |             return !*(x as *const isize);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -577,7 +577,7 @@ LL ~     }
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:284:20
+  --> tests/ui/needless_return.rs:291:20
    |
 LL |           let _ = 42;
    |  ____________________^
@@ -594,7 +594,7 @@ LL +         let _ = 42;
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:291:20
+  --> tests/ui/needless_return.rs:298:20
    |
 LL |         let _ = 42; return;
    |                    ^^^^^^^
@@ -606,7 +606,7 @@ LL +         let _ = 42;
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:303:9
+  --> tests/ui/needless_return.rs:310:9
    |
 LL |         return Ok(format!("ok!"));
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -618,7 +618,7 @@ LL +         Ok(format!("ok!"))
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:305:9
+  --> tests/ui/needless_return.rs:312:9
    |
 LL |         return Err(format!("err!"));
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -630,7 +630,7 @@ LL +         Err(format!("err!"))
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:311:9
+  --> tests/ui/needless_return.rs:318:9
    |
 LL |         return if true { 1 } else { 2 };
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -642,7 +642,7 @@ LL +         if true { 1 } else { 2 }
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:315:9
+  --> tests/ui/needless_return.rs:322:9
    |
 LL |         return if b1 { 0 } else { 1 } | if b2 { 2 } else { 3 } | if b3 { 4 } else { 5 };
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -654,7 +654,7 @@ LL +         (if b1 { 0 } else { 1 } | if b2 { 2 } else { 3 } | if b3 { 4 } else
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:336:5
+  --> tests/ui/needless_return.rs:343:5
    |
 LL |     return { "a".to_string() } + "b" + { "c" };
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^