Removed lintining on never type.

Abstracted repeating strings into statics.

clippy_lints/src/implicit_return.rs

@@ -42,6 +42,9 @@ declare_clippy_lint! {
 
 declare_lint_pass!(ImplicitReturn => [IMPLICIT_RETURN]);
 
+static LINT_BREAK: &str = "change `break` to `return` as shown";
+static LINT_RETURN: &str = "add `return` as shown";
+
 fn lint(cx: &LateContext<'_, '_>, outer_span: Span, inner_span: Span, msg: &str) {
     let outer_span = span_to_outer_expn(outer_span);
     let inner_span = span_to_outer_expn(inner_span);
@@ -66,12 +69,12 @@ fn span_to_outer_expn(span: Span) -> Span {
     }
 }
 
-fn expr_match(cx: &LateContext<'_, '_>, expr: &Expr, ret_ty_is_never: bool) {
+fn expr_match(cx: &LateContext<'_, '_>, expr: &Expr) {
     match &expr.node {
         // loops could be using `break` instead of `return`
         ExprKind::Block(block, ..) | ExprKind::Loop(block, ..) => {
             if let Some(expr) = &block.expr {
-                expr_match(cx, expr, ret_ty_is_never);
+                expr_match(cx, expr);
             }
             // only needed in the case of `break` with `;` at the end
             else if let Some(stmt) = block.stmts.last() {
@@ -81,7 +84,7 @@ fn expr_match(cx: &LateContext<'_, '_>, expr: &Expr, ret_ty_is_never: bool) {
                     if let ExprKind::Break(.., break_expr) = &expr.node;
                     if let Some(break_expr) = break_expr;
                     then {
-                            lint(cx, expr.span, break_expr.span, "change `break` to `return` as shown");
+                            lint(cx, expr.span, break_expr.span, LINT_BREAK);
                     }
                 }
             }
@@ -89,7 +92,7 @@ fn expr_match(cx: &LateContext<'_, '_>, expr: &Expr, ret_ty_is_never: bool) {
         // use `return` instead of `break`
         ExprKind::Break(.., break_expr) => {
             if let Some(break_expr) = break_expr {
-                lint(cx, expr.span, break_expr.span, "change `break` to `return` as shown");
+                lint(cx, expr.span, break_expr.span, LINT_BREAK);
             }
         },
         ExprKind::Match(.., arms, source) => {
@@ -102,38 +105,29 @@ fn expr_match(cx: &LateContext<'_, '_>, expr: &Expr, ret_ty_is_never: bool) {
 
             if check_all_arms {
                 for arm in arms {
-                    expr_match(cx, &arm.body, ret_ty_is_never);
+                    expr_match(cx, &arm.body);
                 }
             } else {
-                expr_match(
+                expr_match(cx, &arms.first().expect("if let doesn't have a single arm").body);
-                    cx,
-                    &arms.first().expect("if let doesn't have a single arm").body,
-                    ret_ty_is_never,
-                );
             }
         },
         // skip if it already has a return statement
         ExprKind::Ret(..) => (),
-        // make sure it's not a call that panics unless we intend to return a panic
+        // make sure it's not a call that panics
         ExprKind::Call(expr, ..) => {
             if_chain! {
                 if let ExprKind::Path(qpath) = &expr.node;
                 if let Some(path_def_id) = resolve_node(cx, qpath, expr.hir_id).opt_def_id();
                 if match_def_path(cx, path_def_id, &BEGIN_PANIC) ||
                     match_def_path(cx, path_def_id, &BEGIN_PANIC_FMT);
-                then {
+                then { }
-                    // only put `return` on panics if the return type of the function/closure is a panic
-                    if ret_ty_is_never {
-                        lint(cx, expr.span, expr.span, "add `return` as shown")
-                    }
-                }
                 else {
-                    lint(cx, expr.span, expr.span, "add `return` as shown")
+                    lint(cx, expr.span, expr.span, LINT_RETURN)
                 }
             }
         },
         // everything else is missing `return`
-        _ => lint(cx, expr.span, expr.span, "add `return` as shown"),
+        _ => lint(cx, expr.span, expr.span, LINT_RETURN),
     }
 }
 
@@ -149,12 +143,11 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ImplicitReturn {
     ) {
         let def_id = cx.tcx.hir().body_owner_def_id(body.id());
         let mir = cx.tcx.optimized_mir(def_id);
-        let ret_ty = mir.return_ty();
 
         // checking return type through MIR, HIR is not able to determine inferred closure return types
         // make sure it's not a macro
-        if !ret_ty.is_unit() && !in_macro_or_desugar(span) {
+        if !mir.return_ty().is_unit() && !in_macro_or_desugar(span) {
-            expr_match(cx, &body.value, ret_ty.is_never());
+            expr_match(cx, &body.value);
         }
     }
 }

tests/ui/implicit_return.rs

@@ -77,10 +77,6 @@ fn test_closure() {
     let _ = || true;
 }
 
-fn test_return_never() -> ! {
-    panic!()
-}
-
 fn test_panic() -> bool {
     panic!()
 }

tests/ui/implicit_return.stderr

@@ -61,16 +61,10 @@ LL |     let _ = || true;
    |                ^^^^ help: add `return` as shown: `return true`
 
 error: missing return statement
-  --> $DIR/implicit_return.rs:81:5
+  --> $DIR/implicit_return.rs:85:5
-   |
-LL |     panic!()
-   |     ^^^^^^^^ help: add `return` as shown: `return panic!()`
-
-error: missing return statement
-  --> $DIR/implicit_return.rs:89:5
    |
 LL |     format!("test {}", "test")
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: add `return` as shown: `return format!("test {}", "test")`
 
-error: aborting due to 12 previous errors
+error: aborting due to 11 previous errors