Small cleanups in assert!() and panic_fmt lint.

m-ou-se · estebank · m-ou-se · commit 0f193d1a62c1 · 2020-10-19T21:14:05.000+02:00
(From the PR feedback.)

Co-authored-by: Esteban Küber &lt;esteban@kuber.com.ar&gt;
diff --git a/compiler/rustc_builtin_macros/src/assert.rs b/compiler/rustc_builtin_macros/src/assert.rs
@@ -27,37 +27,35 @@ pub fn expand_assert<'cx>(
     // context to pick up whichever is currently in scope.
     let sp = cx.with_call_site_ctxt(sp);
 
-    let panic_call = {
-        if let Some(tokens) = custom_message {
-            // Pass the custom message to panic!().
-            cx.expr(
-                sp,
-                ExprKind::MacCall(MacCall {
-                    path: Path::from_ident(Ident::new(sym::panic, sp)),
-                    args: P(MacArgs::Delimited(
-                        DelimSpan::from_single(sp),
-                        MacDelimiter::Parenthesis,
-                        tokens,
-                    )),
-                    prior_type_ascription: None,
-                }),
-            )
-        } else {
-            // Pass our own message directly to $crate::panicking::panic(),
-            // because it might contain `{` and `}` that should always be
-            // passed literally.
-            cx.expr_call_global(
-                sp,
-                cx.std_path(&[sym::panicking, sym::panic]),
-                vec![cx.expr_str(
-                    DUMMY_SP,
-                    Symbol::intern(&format!(
-                        "assertion failed: {}",
-                        pprust::expr_to_string(&cond_expr).escape_debug()
-                    )),
-                )],
-            )
-        }
+    let panic_call = if let Some(tokens) = custom_message {
+        // Pass the custom message to panic!().
+        cx.expr(
+            sp,
+            ExprKind::MacCall(MacCall {
+                path: Path::from_ident(Ident::new(sym::panic, sp)),
+                args: P(MacArgs::Delimited(
+                    DelimSpan::from_single(sp),
+                    MacDelimiter::Parenthesis,
+                    tokens,
+                )),
+                prior_type_ascription: None,
+            }),
+        )
+    } else {
+        // Pass our own message directly to $crate::panicking::panic(),
+        // because it might contain `{` and `}` that should always be
+        // passed literally.
+        cx.expr_call_global(
+            sp,
+            cx.std_path(&[sym::panicking, sym::panic]),
+            vec![cx.expr_str(
+                DUMMY_SP,
+                Symbol::intern(&format!(
+                    "assertion failed: {}",
+                    pprust::expr_to_string(&cond_expr).escape_debug()
+                )),
+            )],
+        )
     };
     let if_expr =
         cx.expr_if(sp, cx.expr(sp, ExprKind::Unary(UnOp::Not, cond_expr)), panic_call, None);
diff --git a/compiler/rustc_lint/src/panic_fmt.rs b/compiler/rustc_lint/src/panic_fmt.rs
@@ -72,8 +72,8 @@ fn check_panic<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>, arg: &'tc
                     }
                     if looks_like_placeholder {
                         cx.struct_span_lint(PANIC_FMT, arg.span.source_callsite(), |lint| {
-                            let mut l = lint.build("Panic message contains an unused formatting placeholder");
-                            l.note("This message is not used as a format string when given without arguments, but will be in a future Rust version");
+                            let mut l = lint.build("panic message contains an unused formatting placeholder");
+                            l.note("this message is not used as a format string when given without arguments, but will be in a future Rust version");
                             if expn.call_site.contains(arg.span) {
                                 l.span_suggestion(
                                     arg.span.shrink_to_hi(),
@@ -92,8 +92,8 @@ fn check_panic<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>, arg: &'tc
                         });
                     } else {
                         cx.struct_span_lint(PANIC_FMT, expn.call_site, |lint| {
-                            let mut l = lint.build("Panic message contains a brace");
-                            l.note("This message is not used as a format string, but will be in a future Rust version");
+                            let mut l = lint.build("panic message contains a brace");
+                            l.note("this message is not used as a format string, but will be in a future Rust version");
                             if expn.call_site.contains(arg.span) {
                                 l.span_suggestion(
                                     arg.span.shrink_to_lo(),
diff --git a/src/test/ui/panic-brace.rs b/src/test/ui/panic-brace.rs
@@ -2,9 +2,9 @@
 
 #[allow(unreachable_code)]
 fn main() {
-    panic!("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} bla"); //~ WARN Panic message contains an unused formatting placeholder
-    debug_assert!(false, "{{}} bla"); //~ WARN Panic message contains a brace
+    panic!("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} bla"); //~ WARN panic message contains an unused formatting placeholder
+    debug_assert!(false, "{{}} bla"); //~ WARN panic message contains a brace
 }
diff --git a/src/test/ui/panic-brace.stderr b/src/test/ui/panic-brace.stderr
@@ -1,35 +1,35 @@
-warning: Panic message contains a brace
+warning: panic message contains a brace
   --> $DIR/panic-brace.rs:5:5
    |
 LL |     panic!("here's a brace: {");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `#[warn(panic_fmt)]` on by default
-   = note: This message is not used as a format string, but will be in a future Rust version
+   = note: this message is not used as a format string, but will be in a future Rust version
 help: add a "{}" format string to use the message literally
    |
 LL |     panic!("{}", "here's a brace: {");
    |            ^^^^^
 
-warning: Panic message contains a brace
+warning: panic message contains a brace
   --> $DIR/panic-brace.rs:6:5
    |
 LL |     std::panic!("another one: }");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: This message is not used as a format string, but will be in a future Rust version
+   = note: this message is not used as a format string, but will be in a future Rust version
 help: add a "{}" format string to use the message literally
    |
 LL |     std::panic!("{}", "another one: }");
    |                 ^^^^^
 
-warning: Panic message contains an unused formatting placeholder
+warning: panic message contains an unused formatting placeholder
   --> $DIR/panic-brace.rs:7:18
    |
 LL |     core::panic!("Hello {}");
    |                  ^^^^^^^^^^
    |
-   = note: This message is not used as a format string when given without arguments, but will be in a future Rust version
+   = note: this message is not used as a format string when given without arguments, but will be in a future Rust version
 help: add the missing argument(s)
    |
 LL |     core::panic!("Hello {}", argument);
@@ -39,13 +39,13 @@ help: or add a "{}" format string to use the message literally
 LL |     core::panic!("{}", "Hello {}");
    |                  ^^^^^
 
-warning: Panic message contains an unused formatting placeholder
+warning: panic message contains an unused formatting placeholder
   --> $DIR/panic-brace.rs:8:20
    |
 LL |     assert!(false, "{:03x} bla");
    |                    ^^^^^^^^^^^^
    |
-   = note: This message is not used as a format string when given without arguments, but will be in a future Rust version
+   = note: this message is not used as a format string when given without arguments, but will be in a future Rust version
 help: add the missing argument(s)
    |
 LL |     assert!(false, "{:03x} bla", argument);
@@ -55,13 +55,13 @@ help: or add a "{}" format string to use the message literally
 LL |     assert!(false, "{}", "{:03x} bla");
    |                    ^^^^^
 
-warning: Panic message contains a brace
+warning: panic message contains a brace
   --> $DIR/panic-brace.rs:9:5
    |
 LL |     debug_assert!(false, "{{}} bla");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: This message is not used as a format string, but will be in a future Rust version
+   = note: this message is not used as a format string, but will be in a future Rust version
 help: add a "{}" format string to use the message literally
    |
 LL |     debug_assert!(false, "{}", "{{}} bla");

Original file line number	Diff line number	Diff line change
`@@ -1,35 +1,35 @@`
`1`		`-warning: Panic message contains a brace`
	`1`	`+warning: panic message contains a brace`
`2`	`2`	`--> $DIR/panic-brace.rs:5:5`
`3`	`3`	`\|`
`4`	`4`	`LL \| panic!("here's a brace: {");`
`5`	`5`	`\| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^`
`6`	`6`	`\|`
`7`	`7`	= note: `#[warn(panic_fmt)]` on by default
`8`		`- = note: This message is not used as a format string, but will be in a future Rust version`
	`8`	`+ = note: this message is not used as a format string, but will be in a future Rust version`
`9`	`9`	`help: add a "{}" format string to use the message literally`
`10`	`10`	`\|`
`11`	`11`	`LL \| panic!("{}", "here's a brace: {");`
`12`	`12`	`\| ^^^^^`
`13`	`13`
`14`		`-warning: Panic message contains a brace`
	`14`	`+warning: panic message contains a brace`
`15`	`15`	`--> $DIR/panic-brace.rs:6:5`
`16`	`16`	`\|`
`17`	`17`	`LL \| std::panic!("another one: }");`
`18`	`18`	`\| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^`
`19`	`19`	`\|`
`20`		`- = note: This message is not used as a format string, but will be in a future Rust version`
	`20`	`+ = note: this message is not used as a format string, but will be in a future Rust version`
`21`	`21`	`help: add a "{}" format string to use the message literally`
`22`	`22`	`\|`
`23`	`23`	`LL \| std::panic!("{}", "another one: }");`
`24`	`24`	`\| ^^^^^`
`25`	`25`
`26`		`-warning: Panic message contains an unused formatting placeholder`
	`26`	`+warning: panic message contains an unused formatting placeholder`
`27`	`27`	`--> $DIR/panic-brace.rs:7:18`
`28`	`28`	`\|`
`29`	`29`	`LL \| core::panic!("Hello {}");`
`30`	`30`	`\| ^^^^^^^^^^`
`31`	`31`	`\|`
`32`		`- = note: This message is not used as a format string when given without arguments, but will be in a future Rust version`
	`32`	`+ = note: this message is not used as a format string when given without arguments, but will be in a future Rust version`
`33`	`33`	`help: add the missing argument(s)`
`34`	`34`	`\|`
`35`	`35`	`LL \| core::panic!("Hello {}", argument);`
`@@ -39,13 +39,13 @@ help: or add a "{}" format string to use the message literally`
`39`	`39`	`LL \| core::panic!("{}", "Hello {}");`
`40`	`40`	`\| ^^^^^`
`41`	`41`
`42`		`-warning: Panic message contains an unused formatting placeholder`
	`42`	`+warning: panic message contains an unused formatting placeholder`
`43`	`43`	`--> $DIR/panic-brace.rs:8:20`
`44`	`44`	`\|`
`45`	`45`	`LL \| assert!(false, "{:03x} bla");`
`46`	`46`	`\| ^^^^^^^^^^^^`
`47`	`47`	`\|`
`48`		`- = note: This message is not used as a format string when given without arguments, but will be in a future Rust version`
	`48`	`+ = note: this message is not used as a format string when given without arguments, but will be in a future Rust version`
`49`	`49`	`help: add the missing argument(s)`
`50`	`50`	`\|`
`51`	`51`	`LL \| assert!(false, "{:03x} bla", argument);`
`@@ -55,13 +55,13 @@ help: or add a "{}" format string to use the message literally`
`55`	`55`	`LL \| assert!(false, "{}", "{:03x} bla");`
`56`	`56`	`\| ^^^^^`
`57`	`57`
`58`		`-warning: Panic message contains a brace`
	`58`	`+warning: panic message contains a brace`
`59`	`59`	`--> $DIR/panic-brace.rs:9:5`
`60`	`60`	`\|`
`61`	`61`	`LL \| debug_assert!(false, "{{}} bla");`
`62`	`62`	`\| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^`
`63`	`63`	`\|`
`64`		`- = note: This message is not used as a format string, but will be in a future Rust version`
	`64`	`+ = note: this message is not used as a format string, but will be in a future Rust version`
`65`	`65`	`help: add a "{}" format string to use the message literally`
`66`	`66`	`\|`
`67`	`67`	`LL \| debug_assert!(false, "{}", "{{}} bla");`