unused-parens: implement for block return values

9 files changed, 50 insertions, 27 deletions

diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
index 0470ab20dc4..e67131b9164 100644
--- a/src/librustc/ty/mod.rs
+++ b/src/librustc/ty/mod.rs
@@ -2410,7 +2410,7 @@ impl<'tcx> AdtDef {
 
     #[inline]
     pub fn variant_range(&self) -> Range<VariantIdx> {
-        (VariantIdx::new(0)..VariantIdx::new(self.variants.len()))
+        VariantIdx::new(0)..VariantIdx::new(self.variants.len())
     }
 
     /// Computes the discriminant value used by a specific variant.
diff --git a/src/librustc/ty/sty.rs b/src/librustc/ty/sty.rs
index 13f623aadb1..837b2fcc500 100644
--- a/src/librustc/ty/sty.rs
+++ b/src/librustc/ty/sty.rs
@@ -529,7 +529,7 @@ impl<'tcx> GeneratorSubsts<'tcx> {
     pub fn variant_range(&self, def_id: DefId, tcx: TyCtxt<'tcx>) -> Range<VariantIdx> {
         // FIXME requires optimized MIR
         let num_variants = tcx.generator_layout(def_id).variant_fields.len();
-        (VariantIdx::new(0)..VariantIdx::new(num_variants))
+        VariantIdx::new(0)..VariantIdx::new(num_variants)
     }
 
     /// The discriminant for the given variant. Panics if the `variant_index` is
diff --git a/src/librustc_data_structures/sorted_map.rs b/src/librustc_data_structures/sorted_map.rs
index b29ffd75940..08706aac11e 100644
--- a/src/librustc_data_structures/sorted_map.rs
+++ b/src/librustc_data_structures/sorted_map.rs
@@ -132,7 +132,7 @@ impl<K: Ord, V> SortedMap<K, V> {
         R: RangeBounds<K>,
     {
         let (start, end) = self.range_slice_indices(range);
-        (&self.data[start..end])
+        &self.data[start..end]
     }
 
     #[inline]
diff --git a/src/librustc_lint/unused.rs b/src/librustc_lint/unused.rs
index 15158c09af0..bb2c4fa1aaf 100644
--- a/src/librustc_lint/unused.rs
+++ b/src/librustc_lint/unused.rs
@@ -544,12 +544,20 @@ impl EarlyLintPass for UnusedParens {
     }
 
     fn check_stmt(&mut self, cx: &EarlyContext<'_>, s: &ast::Stmt) {
-        if let ast::StmtKind::Local(ref local) = s.kind {
-            self.check_unused_parens_pat(cx, &local.pat, false, false);
+        use ast::StmtKind::*;
 
-            if let Some(ref value) = local.init {
-                self.check_unused_parens_expr(cx, &value, "assigned value", false, None, None);
+        match s.kind {
+            Local(ref local) => {
+                self.check_unused_parens_pat(cx, &local.pat, false, false);
+
+                if let Some(ref value) = local.init {
+                    self.check_unused_parens_expr(cx, &value, "assigned value", false, None, None);
+                }
             }
+            Expr(ref expr) => {
+                self.check_unused_parens_expr(cx, &expr, "block return value", false, None, None);
+            }
+            _ => {}
         }
     }
 
diff --git a/src/librustc_mir_build/hair/pattern/_match.rs b/src/librustc_mir_build/hair/pattern/_match.rs
index 20183fd55c8..a2ce224904b 100644
--- a/src/librustc_mir_build/hair/pattern/_match.rs
+++ b/src/librustc_mir_build/hair/pattern/_match.rs
@@ -1530,7 +1530,7 @@ impl<'tcx> IntRange<'tcx> {
         // 2       --------   // 2 -------
         let (lo, hi) = self.boundaries();
         let (other_lo, other_hi) = other.boundaries();
-        (lo == other_hi || hi == other_lo)
+        lo == other_hi || hi == other_lo
     }
 
     fn to_pat(&self, tcx: TyCtxt<'tcx>) -> Pat<'tcx> {
diff --git a/src/librustc_span/source_map.rs b/src/librustc_span/source_map.rs
index 9c7c0f0c8b0..e0b93b9ce25 100644
--- a/src/librustc_span/source_map.rs
+++ b/src/librustc_span/source_map.rs
@@ -774,10 +774,10 @@ impl SourceMap {
         // searching forwards for boundaries we've got somewhere to search.
         let snippet = if let Some(ref src) = local_begin.sf.src {
             let len = src.len();
-            (&src[start_index..len])
+            &src[start_index..len]
         } else if let Some(src) = src.get_source() {
             let len = src.len();
-            (&src[start_index..len])
+            &src[start_index..len]
         } else {
             return 1;
         };
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index f0ef33e2f62..d6f18fda8b2 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -548,11 +548,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
         let st = match style {
             ast::StrStyle::Cooked => (format!("\"{}\"", st.escape_debug())),
             ast::StrStyle::Raw(n) => {
-                (format!(
-                    "r{delim}\"{string}\"{delim}",
-                    delim = "#".repeat(n as usize),
-                    string = st
-                ))
+                format!("r{delim}\"{string}\"{delim}", delim = "#".repeat(n as usize), string = st)
             }
         };
         self.word(st)
diff --git a/src/test/ui/lint/lint-unnecessary-parens.rs b/src/test/ui/lint/lint-unnecessary-parens.rs
index 12ffb6d3c66..4e8339a8e6b 100644
--- a/src/test/ui/lint/lint-unnecessary-parens.rs
+++ b/src/test/ui/lint/lint-unnecessary-parens.rs
@@ -17,6 +17,13 @@ fn unused_parens_around_return_type() -> (u32) { //~ ERROR unnecessary parenthes
     panic!()
 }
 
+fn unused_parens_around_block_return() -> u32 {
+    let foo = {
+        (5) //~ ERROR unnecessary parentheses around block return value
+    };
+    (5) //~ ERROR unnecessary parentheses around block return value
+}
+
 trait Trait {
     fn test(&self);
 }
diff --git a/src/test/ui/lint/lint-unnecessary-parens.stderr b/src/test/ui/lint/lint-unnecessary-parens.stderr
index 541ae7aa4b5..ea58220d20c 100644
--- a/src/test/ui/lint/lint-unnecessary-parens.stderr
+++ b/src/test/ui/lint/lint-unnecessary-parens.stderr
@@ -22,26 +22,38 @@ error: unnecessary parentheses around type
 LL | fn unused_parens_around_return_type() -> (u32) {
    |                                          ^^^^^ help: remove these parentheses
 
+error: unnecessary parentheses around block return value
+  --> $DIR/lint-unnecessary-parens.rs:22:9
+   |
+LL |         (5)
+   |         ^^^ help: remove these parentheses
+
+error: unnecessary parentheses around block return value
+  --> $DIR/lint-unnecessary-parens.rs:24:5
+   |
+LL |     (5)
+   |     ^^^ help: remove these parentheses
+
 error: unnecessary parentheses around function argument
-  --> $DIR/lint-unnecessary-parens.rs:36:9
+  --> $DIR/lint-unnecessary-parens.rs:43:9
    |
 LL |     bar((true));
    |         ^^^^^^ help: remove these parentheses
 
 error: unnecessary parentheses around `if` condition
-  --> $DIR/lint-unnecessary-parens.rs:38:8
+  --> $DIR/lint-unnecessary-parens.rs:45:8
    |
 LL |     if (true) {}
    |        ^^^^^^ help: remove these parentheses
 
 error: unnecessary parentheses around `while` condition
-  --> $DIR/lint-unnecessary-parens.rs:39:11
+  --> $DIR/lint-unnecessary-parens.rs:46:11
    |
 LL |     while (true) {}
    |           ^^^^^^ help: remove these parentheses
 
 warning: denote infinite loops with `loop { ... }`
-  --> $DIR/lint-unnecessary-parens.rs:39:5
+  --> $DIR/lint-unnecessary-parens.rs:46:5
    |
 LL |     while (true) {}
    |     ^^^^^^^^^^^^ help: use `loop`
@@ -49,46 +61,46 @@ LL |     while (true) {}
    = note: `#[warn(while_true)]` on by default
 
 error: unnecessary parentheses around `match` head expression
-  --> $DIR/lint-unnecessary-parens.rs:41:11
+  --> $DIR/lint-unnecessary-parens.rs:48:11
    |
 LL |     match (true) {
    |           ^^^^^^ help: remove these parentheses
 
 error: unnecessary parentheses around `let` head expression
-  --> $DIR/lint-unnecessary-parens.rs:44:16
+  --> $DIR/lint-unnecessary-parens.rs:51:16
    |
 LL |     if let 1 = (1) {}
    |                ^^^ help: remove these parentheses
 
 error: unnecessary parentheses around `let` head expression
-  --> $DIR/lint-unnecessary-parens.rs:45:19
+  --> $DIR/lint-unnecessary-parens.rs:52:19
    |
 LL |     while let 1 = (2) {}
    |                   ^^^ help: remove these parentheses
 
 error: unnecessary parentheses around method argument
-  --> $DIR/lint-unnecessary-parens.rs:59:24
+  --> $DIR/lint-unnecessary-parens.rs:66:24
    |
 LL |     X { y: false }.foo((true));
    |                        ^^^^^^ help: remove these parentheses
 
 error: unnecessary parentheses around assigned value
-  --> $DIR/lint-unnecessary-parens.rs:61:18
+  --> $DIR/lint-unnecessary-parens.rs:68:18
    |
 LL |     let mut _a = (0);
    |                  ^^^ help: remove these parentheses
 
 error: unnecessary parentheses around assigned value
-  --> $DIR/lint-unnecessary-parens.rs:62:10
+  --> $DIR/lint-unnecessary-parens.rs:69:10
    |
 LL |     _a = (0);
    |          ^^^ help: remove these parentheses
 
 error: unnecessary parentheses around assigned value
-  --> $DIR/lint-unnecessary-parens.rs:63:11
+  --> $DIR/lint-unnecessary-parens.rs:70:11
    |
 LL |     _a += (1);
    |           ^^^ help: remove these parentheses
 
-error: aborting due to 13 previous errors
+error: aborting due to 15 previous errors