Use correct edition for panic in [debug_]assert!().

compiler/rustc_builtin_macros/src/assert.rs

@@ -1,10 +1,10 @@
-use rustc_errors::{Applicability, DiagnosticBuilder};
-
+use crate::panic::use_panic_2021;
 use rustc_ast::ptr::P;
 use rustc_ast::token;
 use rustc_ast::tokenstream::{DelimSpan, TokenStream};
 use rustc_ast::{self as ast, *};
 use rustc_ast_pretty::pprust;
+use rustc_errors::{Applicability, DiagnosticBuilder};
 use rustc_expand::base::*;
 use rustc_parse::parser::Parser;
 use rustc_span::symbol::{sym, Ident, Symbol};
@@ -28,7 +28,7 @@ pub fn expand_assert<'cx>(
     let sp = cx.with_call_site_ctxt(span);
 
     let panic_call = if let Some(tokens) = custom_message {
-        let path = if span.rust_2021() {
+        let path = if use_panic_2021(span) {
             // On edition 2021, we always call `$crate::panic::panic_2021!()`.
             Path {
                 span: sp,

compiler/rustc_builtin_macros/src/panic.rs

@@ -2,6 +2,7 @@ use rustc_ast::ptr::P;
 use rustc_ast::tokenstream::{DelimSpan, TokenStream};
 use rustc_ast::*;
 use rustc_expand::base::*;
+use rustc_span::edition::Edition;
 use rustc_span::symbol::sym;
 use rustc_span::Span;
 
@@ -19,7 +20,7 @@ pub fn expand_panic<'cx>(
     sp: Span,
     tts: TokenStream,
 ) -> Box<dyn MacResult + 'cx> {
-    let panic = if sp.rust_2021() { sym::panic_2021 } else { sym::panic_2015 };
+    let panic = if use_panic_2021(sp) { sym::panic_2021 } else { sym::panic_2015 };
 
     let sp = cx.with_call_site_ctxt(sp);
 
@@ -46,3 +47,19 @@ pub fn expand_panic<'cx>(
         ),
     )
 }
+
+pub fn use_panic_2021(mut span: Span) -> bool {
+    // To determine the editon, we check the first span up the expansion
+    // stack that does not have #[allow_internal_unstable(edition_panic)].
+    // (To avoid using the edition of e.g. the assert!() or debug_assert!() definition.)
+    loop {
+        let expn = span.ctxt().outer_expn_data();
+        if let Some(features) = expn.allow_internal_unstable {
+            if features.iter().any(|&f| f == sym::edition_panic) {
+                span = expn.call_site;
+                continue;
+            }
+        }
+        break expn.edition >= Edition::Edition2021;
+    }
+}

compiler/rustc_span/src/symbol.rs

@@ -568,6 +568,7 @@ symbols! {
         dyn_metadata,
         dyn_trait,
         edition_macro_pats,
+        edition_panic,
         eh_catch_typeinfo,
         eh_personality,
         emit_enum,

library/core/src/macros/mod.rs

@@ -210,6 +210,7 @@ pub macro assert_matches {
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_diagnostic_item = "debug_assert_macro"]
+#[allow_internal_unstable(edition_panic)]
 macro_rules! debug_assert {
     ($($arg:tt)*) => (if $crate::cfg!(debug_assertions) { $crate::assert!($($arg)*); })
 }

src/test/ui/rust-2021/panic.rs

@@ -0,0 +1,24 @@
+// edition:2021
+
+fn main() {
+    debug_assert!(false, 123);
+    //~^ ERROR must be a string literal
+    assert!(false, 123);
+    //~^ ERROR must be a string literal
+    panic!(false, 123);
+    //~^ ERROR must be a string literal
+
+    std::debug_assert!(false, 123);
+    //~^ ERROR must be a string literal
+    std::assert!(false, 123);
+    //~^ ERROR must be a string literal
+    std::panic!(false, 123);
+    //~^ ERROR must be a string literal
+
+    core::debug_assert!(false, 123);
+    //~^ ERROR must be a string literal
+    core::assert!(false, 123);
+    //~^ ERROR must be a string literal
+    core::panic!(false, 123);
+    //~^ ERROR must be a string literal
+}

src/test/ui/rust-2021/panic.stderr

@@ -0,0 +1,101 @@
+error: format argument must be a string literal
+  --> $DIR/panic.rs:4:26
+   |
+LL |     debug_assert!(false, 123);
+   |                          ^^^
+   |
+help: you might be missing a string literal to format with
+   |
+LL |     debug_assert!(false, "{}", 123);
+   |                          +++++
+
+error: format argument must be a string literal
+  --> $DIR/panic.rs:6:20
+   |
+LL |     assert!(false, 123);
+   |                    ^^^
+   |
+help: you might be missing a string literal to format with
+   |
+LL |     assert!(false, "{}", 123);
+   |                    +++++
+
+error: format argument must be a string literal
+  --> $DIR/panic.rs:8:12
+   |
+LL |     panic!(false, 123);
+   |            ^^^^^
+   |
+help: you might be missing a string literal to format with
+   |
+LL |     panic!("{} {}", false, 123);
+   |            ++++++++
+
+error: format argument must be a string literal
+  --> $DIR/panic.rs:11:31
+   |
+LL |     std::debug_assert!(false, 123);
+   |                               ^^^
+   |
+help: you might be missing a string literal to format with
+   |
+LL |     std::debug_assert!(false, "{}", 123);
+   |                               +++++
+
+error: format argument must be a string literal
+  --> $DIR/panic.rs:13:25
+   |
+LL |     std::assert!(false, 123);
+   |                         ^^^
+   |
+help: you might be missing a string literal to format with
+   |
+LL |     std::assert!(false, "{}", 123);
+   |                         +++++
+
+error: format argument must be a string literal
+  --> $DIR/panic.rs:15:17
+   |
+LL |     std::panic!(false, 123);
+   |                 ^^^^^
+   |
+help: you might be missing a string literal to format with
+   |
+LL |     std::panic!("{} {}", false, 123);
+   |                 ++++++++
+
+error: format argument must be a string literal
+  --> $DIR/panic.rs:18:32
+   |
+LL |     core::debug_assert!(false, 123);
+   |                                ^^^
+   |
+help: you might be missing a string literal to format with
+   |
+LL |     core::debug_assert!(false, "{}", 123);
+   |                                +++++
+
+error: format argument must be a string literal
+  --> $DIR/panic.rs:20:26
+   |
+LL |     core::assert!(false, 123);
+   |                          ^^^
+   |
+help: you might be missing a string literal to format with
+   |
+LL |     core::assert!(false, "{}", 123);
+   |                          +++++
+
+error: format argument must be a string literal
+  --> $DIR/panic.rs:22:18
+   |
+LL |     core::panic!(false, 123);
+   |                  ^^^^^
+   |
+help: you might be missing a string literal to format with
+   |
+LL |     core::panic!("{} {}", false, 123);
+   |                  ++++++++
+
+error: aborting due to 9 previous errors
+