Remove braces from Rust 2015 panic macro

library/std/src/panic.rs

@@ -14,19 +14,19 @@ use crate::thread::Result;
 #[cfg_attr(not(test), rustc_diagnostic_item = "std_panic_2015_macro")]
 #[rustc_macro_transparency = "semitransparent"]
 pub macro panic_2015 {
-    () => ({
+    () => (
         $crate::rt::begin_panic("explicit panic")
-    }),
-    ($msg:expr $(,)?) => ({
+    ),
+    ($msg:expr $(,)?) => (
         $crate::rt::begin_panic($msg)
-    }),
+    ),
     // Special-case the single-argument case for const_panic.
-    ("{}", $arg:expr $(,)?) => ({
+    ("{}", $arg:expr $(,)?) => (
         $crate::rt::panic_display(&$arg)
-    }),
-    ($fmt:expr, $($arg:tt)+) => ({
+    ),
+    ($fmt:expr, $($arg:tt)+) => (
         $crate::rt::panic_fmt($crate::const_format_args!($fmt, $($arg)+))
-    }),
+    ),
 }
 
 #[doc(hidden)]

src/test/ui/block-result/issue-5500.rs

@@ -2,6 +2,6 @@ fn main() {
     &panic!()
     //~^ ERROR mismatched types
     //~| expected unit type `()`
-    //~| found reference `&_`
-    //~| expected `()`, found reference
+    //~| found reference `&!`
+    //~| expected `()`, found `&!`
 }

src/test/ui/block-result/issue-5500.stderr

@@ -4,15 +4,10 @@ error[E0308]: mismatched types
 LL | fn main() {
    |           - expected `()` because of default return type
 LL |     &panic!()
-   |     ^^^^^^^^^ expected `()`, found reference
+   |     ^^^^^^^^^ expected `()`, found `&!`
    |
    = note: expected unit type `()`
-              found reference `&_`
-help: consider removing the borrow
-   |
-LL -     &panic!()
-LL +     panic!()
-   | 
+              found reference `&!`
 
 error: aborting due to previous error
 

src/test/ui/diverging-tuple-parts-39485.stderr

@@ -1,20 +1,13 @@
 error[E0308]: mismatched types
   --> $DIR/diverging-tuple-parts-39485.rs:8:5
    |
+LL | fn g() {
+   |        - help: try adding a return type: `-> &!`
 LL |     &panic!()
-   |     ^^^^^^^^^ expected `()`, found reference
+   |     ^^^^^^^^^ expected `()`, found `&!`
    |
    = note: expected unit type `()`
-              found reference `&_`
-help: try adding a return type
-   |
-LL | fn g() -> &_ {
-   |        +++++
-help: consider removing the borrow
-   |
-LL -     &panic!()
-LL +     panic!()
-   | 
+              found reference `&!`
 
 error[E0308]: mismatched types
   --> $DIR/diverging-tuple-parts-39485.rs:12:5

src/test/ui/issues/issue-5500-1.rs

@@ -11,5 +11,5 @@ struct TrieMapIterator<'a> {
 fn main() {
     let a = 5;
     let _iter = TrieMapIterator{node: &a};
-    _iter.node = &panic!()
+    _iter.node = &{panic!()}
 }

src/tools/clippy/clippy_lints/src/if_then_panic.rs

@@ -61,9 +61,7 @@ impl LateLintPass<'_> for IfThenPanic {
                     }
                 } else {
                     if_chain! {
-                        if let ExprKind::Block(block, _) = semi.kind;
-                        if let Some(init) = block.expr;
-                        if let ExprKind::Call(_, [format_args]) = init.kind;
+                        if let ExprKind::Call(_, [format_args]) = semi.kind;
 
                         then {
                             format_args.span

src/tools/clippy/clippy_lints/src/matches.rs

@@ -968,8 +968,7 @@ fn check_wild_err_arm<'tcx>(cx: &LateContext<'tcx>, ex: &Expr<'tcx>, arms: &[Arm
                     }
                     if_chain! {
                         if matching_wild;
-                        if let ExprKind::Block(block, _) = arm.body.kind;
-                        if is_panic_block(block);
+                        if is_panic_call(arm.body);
                         then {
                             // `Err(_)` or `Err(_e)` arm with `panic!` found
                             span_lint_and_note(cx,
@@ -1172,14 +1171,19 @@ fn check_wild_enum_match(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>])
 }
 
 // If the block contains only a `panic!` macro (as expression or statement)
-fn is_panic_block(block: &Block<'_>) -> bool {
-    match (&block.expr, block.stmts.len(), block.stmts.first()) {
-        (&Some(exp), 0, _) => is_expn_of(exp.span, "panic").is_some() && is_expn_of(exp.span, "unreachable").is_none(),
-        (&None, 1, Some(stmt)) => {
-            is_expn_of(stmt.span, "panic").is_some() && is_expn_of(stmt.span, "unreachable").is_none()
-        },
-        _ => false,
-    }
+fn is_panic_call(expr: &Expr<'_>) -> bool {
+    // Unwrap any wrapping blocks
+    let span = if let ExprKind::Block(block, _) = expr.kind {
+        match (&block.expr, block.stmts.len(), block.stmts.first()) {
+            (&Some(exp), 0, _) => exp.span,
+            (&None, 1, Some(stmt)) => stmt.span,
+            _ => return false,
+        }
+    } else {
+        expr.span
+    };
+
+    is_expn_of(span, "panic").is_some() && is_expn_of(span, "unreachable").is_none()
 }
 
 fn check_match_ref_pats<'a, 'b, I>(cx: &LateContext<'_>, ex: &Expr<'_>, pats: I, expr: &Expr<'_>)

src/tools/clippy/clippy_utils/src/higher.rs

@@ -615,9 +615,7 @@ impl PanicExpn<'tcx> {
     /// Parses an expanded `panic!` invocation
     pub fn parse(expr: &'tcx Expr<'tcx>) -> Option<Self> {
         if_chain! {
-            if let ExprKind::Block(block, _) = expr.kind;
-            if let Some(init) = block.expr;
-            if let ExprKind::Call(_, [format_args]) = init.kind;
+            if let ExprKind::Call(_, [format_args]) = expr.kind;
             let expn_data = expr.span.ctxt().outer_expn_data();
             if let Some(format_args) = FormatArgsExpn::parse(format_args);
             then {

src/tools/clippy/tests/ui/diverging_sub_expression.stderr

@@ -30,11 +30,19 @@ error: sub-expression diverges
 LL |             3 => true || diverge(),
    |                          ^^^^^^^^^
 
+error: sub-expression diverges
+  --> $DIR/diverging_sub_expression.rs:37:30
+   |
+LL |                 _ => true || panic!("boo"),
+   |                              ^^^^^^^^^^^^^
+   |
+   = note: this error originates in the macro `$crate::panic::panic_2015` (in Nightly builds, run with -Z macro-backtrace for more info)
+
 error: sub-expression diverges
   --> $DIR/diverging_sub_expression.rs:39:26
    |
 LL |             _ => true || break,
    |                          ^^^^^
 
-error: aborting due to 6 previous errors
+error: aborting due to 7 previous errors
 

src/tools/clippy/tests/ui/if_then_panic_core.fixed

@@ -0,0 +1,42 @@
+// run-rustfix
+#![crate_type = "lib"]
+#![no_std]
+#![warn(clippy::if_then_panic)]
+
+pub fn main() {
+    let a = &[1, 2, 3];
+    let c = Some(2);
+    if !a.is_empty()
+        && a.len() == 3
+        && c != None
+        && !a.is_empty()
+        && a.len() == 3
+        && !a.is_empty()
+        && a.len() == 3
+        && !a.is_empty()
+        && a.len() == 3
+    {
+        panic!("qaqaq{:?}", a);
+    }
+    assert!(a.is_empty(), "qaqaq{:?}", a);
+    assert!(a.is_empty(), "qwqwq");
+    if a.len() == 3 {
+        format_args!("qwq");
+        format_args!("qwq");
+        format_args!("qwq");
+    }
+    if let Some(b) = c {
+        panic!("orz {}", b);
+    }
+    if a.len() == 3 {
+        panic!("qaqaq");
+    } else {
+        format_args!("qwq");
+    }
+    let b = &[1, 2, 3];
+    assert!(!b.is_empty(), "panic1");
+    assert!(!(b.is_empty() && a.is_empty()), "panic2");
+    assert!(!(a.is_empty() && !b.is_empty()), "panic3");
+    assert!(!(b.is_empty() || a.is_empty()), "panic4");
+    assert!(!(a.is_empty() || !b.is_empty()), "panic5");
+}

src/tools/clippy/tests/ui/if_then_panic_core.rs

@@ -0,0 +1,56 @@
+// run-rustfix
+#![crate_type = "lib"]
+#![no_std]
+#![warn(clippy::if_then_panic)]
+
+pub fn main() {
+    let a = &[1, 2, 3];
+    let c = Some(2);
+    if !a.is_empty()
+        && a.len() == 3
+        && c != None
+        && !a.is_empty()
+        && a.len() == 3
+        && !a.is_empty()
+        && a.len() == 3
+        && !a.is_empty()
+        && a.len() == 3
+    {
+        panic!("qaqaq{:?}", a);
+    }
+    if !a.is_empty() {
+        panic!("qaqaq{:?}", a);
+    }
+    if !a.is_empty() {
+        panic!("qwqwq");
+    }
+    if a.len() == 3 {
+        format_args!("qwq");
+        format_args!("qwq");
+        format_args!("qwq");
+    }
+    if let Some(b) = c {
+        panic!("orz {}", b);
+    }
+    if a.len() == 3 {
+        panic!("qaqaq");
+    } else {
+        format_args!("qwq");
+    }
+    let b = &[1, 2, 3];
+    if b.is_empty() {
+        panic!("panic1");
+    }
+    if b.is_empty() && a.is_empty() {
+        panic!("panic2");
+    }
+    if a.is_empty() && !b.is_empty() {
+        panic!("panic3");
+    }
+    if b.is_empty() || a.is_empty() {
+        panic!("panic4");
+    }
+    if a.is_empty() || !b.is_empty() {
+        panic!("panic5");
+    }
+}

src/tools/clippy/tests/ui/if_then_panic_core.stderr

@@ -0,0 +1,60 @@
+error: only a `panic!` in `if`-then statement
+  --> $DIR/if_then_panic_core.rs:21:5
+   |
+LL | /     if !a.is_empty() {
+LL | |         panic!("qaqaq{:?}", a);
+LL | |     }
+   | |_____^ help: try: `assert!(a.is_empty(), "qaqaq{:?}", a);`
+   |
+   = note: `-D clippy::if-then-panic` implied by `-D warnings`
+
+error: only a `panic!` in `if`-then statement
+  --> $DIR/if_then_panic_core.rs:24:5
+   |
+LL | /     if !a.is_empty() {
+LL | |         panic!("qwqwq");
+LL | |     }
+   | |_____^ help: try: `assert!(a.is_empty(), "qwqwq");`
+
+error: only a `panic!` in `if`-then statement
+  --> $DIR/if_then_panic_core.rs:41:5
+   |
+LL | /     if b.is_empty() {
+LL | |         panic!("panic1");
+LL | |     }
+   | |_____^ help: try: `assert!(!b.is_empty(), "panic1");`
+
+error: only a `panic!` in `if`-then statement
+  --> $DIR/if_then_panic_core.rs:44:5
+   |
+LL | /     if b.is_empty() && a.is_empty() {
+LL | |         panic!("panic2");
+LL | |     }
+   | |_____^ help: try: `assert!(!(b.is_empty() && a.is_empty()), "panic2");`
+
+error: only a `panic!` in `if`-then statement
+  --> $DIR/if_then_panic_core.rs:47:5
+   |
+LL | /     if a.is_empty() && !b.is_empty() {
+LL | |         panic!("panic3");
+LL | |     }
+   | |_____^ help: try: `assert!(!(a.is_empty() && !b.is_empty()), "panic3");`
+
+error: only a `panic!` in `if`-then statement
+  --> $DIR/if_then_panic_core.rs:50:5
+   |
+LL | /     if b.is_empty() || a.is_empty() {
+LL | |         panic!("panic4");
+LL | |     }
+   | |_____^ help: try: `assert!(!(b.is_empty() || a.is_empty()), "panic4");`
+
+error: only a `panic!` in `if`-then statement
+  --> $DIR/if_then_panic_core.rs:53:5
+   |
+LL | /     if a.is_empty() || !b.is_empty() {
+LL | |         panic!("panic5");
+LL | |     }
+   | |_____^ help: try: `assert!(!(a.is_empty() || !b.is_empty()), "panic5");`
+
+error: aborting due to 7 previous errors
+

src/tools/clippy/tests/ui/issue-7447.rs

@@ -19,6 +19,7 @@ pub struct ByteView<'a> {
     backing: Arc<ByteViewBacking<'a>>,
 }
 
+#[allow(clippy::diverging_sub_expression)]
 fn main() {
     byte_view(panic!());
     group_entries(panic!());