Take in account the unreachable! macro in the non_fmt_panic lint

rust-lang · Feb 11, 2022 · 22f1800 · 22f1800
1 parent 5140d6d
commit 22f1800
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Showing 9 changed files with 161 additions and 35 deletions.
diff --git a/compiler/rustc_hir/src/lang_items.rs b/compiler/rustc_hir/src/lang_items.rs
@@ -285,7 +285,6 @@ language_item_table! {
     Panic,                   sym::panic,               panic_fn,                   Target::Fn,             GenericRequirement::Exact(0);
     PanicFmt,                sym::panic_fmt,           panic_fmt,                  Target::Fn,             GenericRequirement::None;
     PanicDisplay,            sym::panic_display,       panic_display,              Target::Fn,             GenericRequirement::None;
-    PanicStr,                sym::panic_str,           panic_str,                  Target::Fn,             GenericRequirement::None;
     ConstPanicFmt,           sym::const_panic_fmt,     const_panic_fmt,            Target::Fn,             GenericRequirement::None;
     PanicBoundsCheck,        sym::panic_bounds_check,  panic_bounds_check_fn,      Target::Fn,             GenericRequirement::Exact(0);
     PanicInfo,               sym::panic_info,          panic_info,                 Target::Struct,         GenericRequirement::None;

diff --git a/compiler/rustc_lint/src/non_fmt_panic.rs b/compiler/rustc_lint/src/non_fmt_panic.rs
@@ -49,9 +49,11 @@ impl<'tcx> LateLintPass<'tcx> for NonPanicFmt {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'tcx>) {
         if let hir::ExprKind::Call(f, [arg]) = &expr.kind {
             if let &ty::FnDef(def_id, _) = cx.typeck_results().expr_ty(f).kind() {
+                let f_diagnostic_name = cx.tcx.get_diagnostic_name(def_id);
+
                 if Some(def_id) == cx.tcx.lang_items().begin_panic_fn()
                     || Some(def_id) == cx.tcx.lang_items().panic_fn()
-                    || Some(def_id) == cx.tcx.lang_items().panic_str()
+                    || f_diagnostic_name == Some(sym::panic_str)
                 {
                     if let Some(id) = f.span.ctxt().outer_expn_data().macro_def_id {
                         if matches!(
@@ -61,6 +63,22 @@ impl<'tcx> LateLintPass<'tcx> for NonPanicFmt {
                             check_panic(cx, f, arg);
                         }
                     }
+                } else if f_diagnostic_name == Some(sym::unreachable_display) {
+                    if let Some(id) = f.span.ctxt().outer_expn_data().macro_def_id {
+                        if cx.tcx.is_diagnostic_item(sym::unreachable_2015_macro, id) {
+                            check_panic(
+                                cx,
+                                f,
+                                // This is safe because we checked above that the callee is indeed
+                                // unreachable_display
+                                match &arg.kind {
+                                    // Get the borrowed arg not the borrow
+                                    hir::ExprKind::AddrOf(ast::BorrowKind::Ref, _, arg) => arg,
+                                    _ => bug!("call to unreachable_display without borrow"),
+                                },
+                            );
+                        }
+                    }
                 }
             }
         }
@@ -85,8 +103,8 @@ fn check_panic<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>, arg: &'tc
         return;
     }
 
-    // Find the span of the argument to `panic!()`, before expansion in the
-    // case of `panic!(some_macro!())`.
+    // Find the span of the argument to `panic!()` or `unreachable!`, before expansion in the
+    // case of `panic!(some_macro!())` or `unreachable!(some_macro!())`.
     // We don't use source_callsite(), because this `panic!(..)` might itself
     // be expanded from another macro, in which case we want to stop at that
     // expansion.
@@ -319,6 +337,7 @@ fn panic_call<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>) -> (Span,
                 | sym::std_panic_macro
                 | sym::assert_macro
                 | sym::debug_assert_macro
+                | sym::unreachable_macro
         ) {
             break;
         }

diff --git a/library/core/src/panicking.rs b/library/core/src/panicking.rs
@@ -50,7 +50,8 @@ pub const fn panic(expr: &'static str) -> ! {
 
 #[inline]
 #[track_caller]
-#[lang = "panic_str"] // needed for `non-fmt-panics` lint
+#[rustc_diagnostic_item = "panic_str"]
+#[rustc_const_unstable(feature = "core_panic", issue = "none")]
 pub const fn panic_str(expr: &str) -> ! {
     panic_display(&expr);
 }

diff --git a/src/test/ui/macros/unreachable-arg.edition_2021.stderr b/src/test/ui/macros/unreachable-arg.edition_2021.stderr
@@ -0,0 +1,13 @@
+error: format argument must be a string literal
+  --> $DIR/unreachable-arg.rs:15:18
+   |
+LL |     unreachable!(a);
+   |                  ^
+   |
+help: you might be missing a string literal to format with
+   |
+LL |     unreachable!("{}", a);
+   |                  +++++
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/macros/unreachable-arg.rs b/src/test/ui/macros/unreachable-arg.rs
@@ -0,0 +1,16 @@
+// ignore-emscripten no processes
+
+// revisions: edition_2015 edition_2021
+// [edition_2015]edition:2015
+// [edition_2021]edition:2021
+// [edition_2015]run-fail
+// [edition_2021]check-fail
+// [edition_2015]error-pattern:internal error: entered unreachable code: hello
+// [edition_2021]error-pattern:format argument must be a string literal
+
+#![allow(non_fmt_panics)]
+
+fn main() {
+    let a = "hello";
+    unreachable!(a);
+}
diff --git a/src/test/ui/macros/unreachable-format-arg.rs b/src/test/ui/macros/unreachable-format-arg.rs
@@ -7,6 +7,8 @@
 // [edition_2015]error-pattern:internal error: entered unreachable code: x is {x}
 // [edition_2021]error-pattern:internal error: entered unreachable code: x is 5
 
+#![allow(non_fmt_panics)]
+
 fn main() {
     let x = 5;
     unreachable!("x is {x}");

diff --git a/src/test/ui/non-fmt-panic.fixed b/src/test/ui/non-fmt-panic.fixed
@@ -11,6 +11,7 @@ static S: &str = "{bla}";
 #[allow(unreachable_code)]
 fn main() {
     panic!("{}", "here's a brace: {"); //~ WARN panic message contains a brace
+    unreachable!("{}", "here's a brace: {"); //~ WARN panic message contains a brace
     std::panic!("{}", "another one: }"); //~ WARN panic message contains a brace
     core::panic!("{}", "Hello {}"); //~ WARN panic message contains an unused formatting placeholder
     assert!(false, "{}", "{:03x} {test} bla");
@@ -24,6 +25,8 @@ fn main() {
     debug_assert!(false, "{}", "{{}} bla"); //~ WARN panic message contains braces
     panic!("{}", C); //~ WARN panic message is not a string literal
     panic!("{}", S); //~ WARN panic message is not a string literal
+    unreachable!("{}", S); //~ WARN panic message is not a string literal
+    unreachable!("{}", S); //~ WARN panic message is not a string literal
     std::panic::panic_any(123); //~ WARN panic message is not a string literal
     core::panic!("{}", &*"abc"); //~ WARN panic message is not a string literal
     std::panic::panic_any(Some(123)); //~ WARN panic message is not a string literal
@@ -41,8 +44,10 @@ fn main() {
     }
 
     std::panic::panic_any(a!()); //~ WARN panic message is not a string literal
+    unreachable!("{}", a!()); //~ WARN panic message is not a string literal
 
     panic!("{}", 1); //~ WARN panic message is not a string literal
+    unreachable!("{}", 1); //~ WARN panic message is not a string literal
     assert!(false, "{}", 1); //~ WARN panic message is not a string literal
     debug_assert!(false, "{}", 1); //~ WARN panic message is not a string literal
 

diff --git a/src/test/ui/non-fmt-panic.rs b/src/test/ui/non-fmt-panic.rs
@@ -11,6 +11,7 @@ static S: &str = "{bla}";
 #[allow(unreachable_code)]
 fn main() {
     panic!("here's a brace: {"); //~ WARN panic message contains a brace
+    unreachable!("here's a brace: {"); //~ WARN panic message contains a brace
     std::panic!("another one: }"); //~ WARN panic message contains a brace
     core::panic!("Hello {}"); //~ WARN panic message contains an unused formatting placeholder
     assert!(false, "{:03x} {test} bla");
@@ -24,6 +25,8 @@ fn main() {
     debug_assert!(false, "{{}} bla"); //~ WARN panic message contains braces
     panic!(C); //~ WARN panic message is not a string literal
     panic!(S); //~ WARN panic message is not a string literal
+    unreachable!(S); //~ WARN panic message is not a string literal
+    unreachable!(S); //~ WARN panic message is not a string literal
     std::panic!(123); //~ WARN panic message is not a string literal
     core::panic!(&*"abc"); //~ WARN panic message is not a string literal
     panic!(Some(123)); //~ WARN panic message is not a string literal
@@ -41,8 +44,10 @@ fn main() {
     }
 
     panic!(a!()); //~ WARN panic message is not a string literal
+    unreachable!(a!()); //~ WARN panic message is not a string literal
 
     panic!(format!("{}", 1)); //~ WARN panic message is not a string literal
+    unreachable!(format!("{}", 1)); //~ WARN panic message is not a string literal
     assert!(false, format!("{}", 1)); //~ WARN panic message is not a string literal
     debug_assert!(false, format!("{}", 1)); //~ WARN panic message is not a string literal