fix(semicolon_inside_block): don't lint if block is in parens

Author: ada4a

clippy_lints/src/semicolon_block.rs

@@ -1,5 +1,6 @@
 use clippy_config::Conf;
 use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::source::SpanRangeExt;
 use rustc_errors::Applicability;
 use rustc_hir::{Block, Expr, ExprKind, Stmt, StmtKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
@@ -82,6 +83,19 @@ impl SemicolonBlock {
         let insert_span = tail.span.source_callsite().shrink_to_hi();
         let remove_span = semi_span.with_lo(block.span.hi());
 
+        // If the block is surrounded by parens (`({ 0 });`), the author probably knows what
+        // they're doing and why, so don't get in their way.
+        //
+        // This has the additional benefit of stopping the block being parsed as a function call:
+        // ```
+        // fn foo() {
+        //     ({ 0 }); // if we remove this `;`, this will parse as a `({ 0 })(5);` function call
+        //     (5);
+        // }
+        if remove_span.check_source_text(cx, |src| src.contains(')')) {
+            return;
+        }
+
         if self.semicolon_inside_block_ignore_singleline && get_line(cx, remove_span) == get_line(cx, insert_span) {
             return;
         }

tests/ui/semicolon_inside_block.fixed

@@ -3,7 +3,8 @@
     clippy::unused_unit,
     clippy::unnecessary_operation,
     clippy::no_effect,
-    clippy::single_element_loop
+    clippy::single_element_loop,
+    clippy::double_parens
 )]
 #![warn(clippy::semicolon_inside_block)]
 
@@ -87,6 +88,18 @@ fn main() {
     unit_fn_block()
 }
 
+#[rustfmt::skip]
+fn issue15380() {
+    ( {0;0});
+
+    ({
+        0;
+        0
+    });
+
+    (({ 0 }))      ;
+}
+
 pub fn issue15388() {
     #[rustfmt::skip]
     {0; 0};

tests/ui/semicolon_inside_block.rs

@@ -3,7 +3,8 @@
     clippy::unused_unit,
     clippy::unnecessary_operation,
     clippy::no_effect,
-    clippy::single_element_loop
+    clippy::single_element_loop,
+    clippy::double_parens
 )]
 #![warn(clippy::semicolon_inside_block)]
 
@@ -87,6 +88,18 @@ fn main() {
     unit_fn_block()
 }
 
+#[rustfmt::skip]
+fn issue15380() {
+    ( {0;0});
+
+    ({
+        0;
+        0
+    });
+
+    (({ 0 }))      ;
+}
+
 pub fn issue15388() {
     #[rustfmt::skip]
     {0; 0};

tests/ui/semicolon_inside_block.stderr

@@ -1,5 +1,5 @@
 error: consider moving the `;` inside the block for consistent formatting
-  --> tests/ui/semicolon_inside_block.rs:38:5
+  --> tests/ui/semicolon_inside_block.rs:39:5
    |
 LL |     { unit_fn_block() };
    |     ^^^^^^^^^^^^^^^^^^^^
@@ -13,7 +13,7 @@ LL +     { unit_fn_block(); }
    |
 
 error: consider moving the `;` inside the block for consistent formatting
-  --> tests/ui/semicolon_inside_block.rs:40:5
+  --> tests/ui/semicolon_inside_block.rs:41:5
    |
 LL |     unsafe { unit_fn_block() };
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -25,7 +25,7 @@ LL +     unsafe { unit_fn_block(); }
    |
 
 error: consider moving the `;` inside the block for consistent formatting
-  --> tests/ui/semicolon_inside_block.rs:49:5
+  --> tests/ui/semicolon_inside_block.rs:50:5
    |
 LL | /     {
 LL | |
@@ -41,7 +41,7 @@ LL ~     }
    |
 
 error: consider moving the `;` inside the block for consistent formatting
-  --> tests/ui/semicolon_inside_block.rs:63:5
+  --> tests/ui/semicolon_inside_block.rs:64:5
    |
 LL |     { m!(()) };
    |     ^^^^^^^^^^^