Clarify conditionals for clippy

Remove double-check of is_mod in format_extern
Collapse nested if in is_block_closure_forced
Use map instead of and_then in rewrite_last_closure
Collapse nested if in impl Rewrite for ast::Ty
Collapse nested if in format_expr
Collapse nested if in merge_use_trees_inner

src/formatting/closures.rs

@@ -364,20 +364,20 @@ pub(crate) fn rewrite_last_closure(
 
         // We force to use block for the body of the closure for certain kinds of expressions.
         if is_block_closure_forced(context, body, capture) {
-            return rewrite_closure_with_block(body, &prefix, context, body_shape).and_then(
+            return rewrite_closure_with_block(body, &prefix, context, body_shape).map(
                 |body_str| {
                     // If the expression can fit in a single line, we need not force block closure.
                     if body_str.lines().count() <= 7 {
                         match rewrite_closure_expr(body, &prefix, context, shape) {
                             Some(ref single_line_body_str)
                                 if !single_line_body_str.contains('\n') =>
                             {
-                                Some(single_line_body_str.clone())
+                                single_line_body_str.clone()
                             }
-                            _ => Some(body_str),
+                            _ => body_str,
                         }
                     } else {
-                        Some(body_str)
+                        body_str
                     }
                 },
             );
@@ -415,15 +415,13 @@ fn is_block_closure_forced(
     // If we are inside macro, we do not want to add or remove block from closure body.
     if context.inside_macro() {
         false
-    } else {
-        if let ast::ExprKind::Match(..) = expr.kind {
-            let is_move_closure_without_brace = capture == ast::CaptureBy::Value
-                && !context.snippet(expr.span).trim().starts_with('{');
+    } else if let ast::ExprKind::Match(..) = expr.kind {
+        let is_move_closure_without_brace =
+            capture == ast::CaptureBy::Value && !context.snippet(expr.span).trim().starts_with('{');
 
-            is_block_closure_forced_inner(expr) || is_move_closure_without_brace
-        } else {
-            is_block_closure_forced_inner(expr)
-        }
+        is_block_closure_forced_inner(expr) || is_move_closure_without_brace
+    } else {
+        is_block_closure_forced_inner(expr)
     }
 }
 

src/formatting/expr.rs

@@ -80,12 +80,10 @@ pub(crate) fn format_expr(
         ast::ExprKind::Lit(ref l) => {
             if let Some(expr_rw) = rewrite_literal(context, l, shape) {
                 Some(expr_rw)
+            } else if let LitKind::StrRaw(_) = l.token.kind {
+                Some(context.snippet(l.span).trim().into())
             } else {
-                if let LitKind::StrRaw(_) = l.token.kind {
-                    Some(context.snippet(l.span).trim().into())
-                } else {
-                    None
-                }
+                None
             }
         }
         ast::ExprKind::Call(ref callee, ref args) => {

src/formatting/imports.rs

@@ -626,12 +626,10 @@ fn merge_use_trees_inner(trees: &mut Vec<UseTree>, use_tree: UseTree) {
                 return;
             }
         }
-    } else {
-        if let Some(tree) = similar_trees.max_by_key(|tree| tree.path.len()) {
-            if tree.path.len() > 1 {
-                tree.merge(&use_tree);
-                return;
-            }
+    } else if let Some(tree) = similar_trees.max_by_key(|tree| tree.path.len()) {
+        if tree.path.len() > 1 {
+            tree.merge(&use_tree);
+            return;
         }
     }
     trees.push(use_tree);

src/formatting/types.rs

@@ -625,10 +625,12 @@ impl Rewrite for ast::Ty {
                 let shape = if is_dyn { shape.offset_left(4)? } else { shape };
                 let mut res = bounds.rewrite(context, shape)?;
                 // We may have falsely removed a trailing `+` inside macro call.
-                if context.inside_macro() && bounds.len() == 1 {
-                    if context.snippet(self.span).ends_with('+') && !res.ends_with('+') {
-                        res.push('+');
-                    }
+                if context.inside_macro()
+                    && bounds.len() == 1
+                    && context.snippet(self.span).ends_with('+')
+                    && !res.ends_with('+')
+                {
+                    res.push('+');
                 }
                 if is_dyn {
                     Some(format!("dyn {}", res))

src/formatting/utils.rs

@@ -154,7 +154,7 @@ pub(crate) fn format_extern(
 ) -> Cow<'static, str> {
     let format_explicit_abi = |abi: &str| Cow::from(format!(r#"extern "{}" "#, abi));
     let explicit_conversion_preserves_semantics =
-        || !is_mod || (is_mod && attrs.map_or(true, |a| a.is_empty()));
+        || !is_mod || attrs.map_or(true, |a| a.is_empty());
 
     match ext {
         ast::Extern::None if !is_mod => Cow::from(""),