Let statement should rewrite rhs with comments after equal sign

Author: johnhuichen

.gitignore

@@ -23,3 +23,6 @@ tests/cargo-fmt/**/target
 .idea/
 .vscode/
 *~
+
+# Git
+.git/

src/items.rs

@@ -131,14 +131,32 @@ impl Rewrite for ast::Local {
                 .sub_width(1)
                 .max_width_error(shape.width, self.span())?;
 
-            result = rewrite_assign_rhs(
-                context,
-                result,
-                init,
-                &RhsAssignKind::Expr(&init.kind, init.span),
-                nested_shape,
-            )
-            .max_width_error(shape.width, self.span())?;
+            let maybe_comment_span = context
+                .snippet_provider
+                .opt_span_after(self.span, "=")
+                .map(|op_lo| mk_sp(op_lo, init.span.lo()));
+
+            if maybe_comment_span.map_or(true, |span| context.snippet(span).trim().len() == 0) {
+                result = rewrite_assign_rhs(
+                    context,
+                    result,
+                    init,
+                    &RhsAssignKind::Expr(&init.kind, init.span),
+                    nested_shape,
+                )
+                .max_width_error(shape.width, self.span())?;
+            } else {
+                result = rewrite_assign_rhs_with_comments(
+                    context,
+                    result,
+                    &*init,
+                    nested_shape,
+                    &RhsAssignKind::Expr(&init.kind, init.span),
+                    RhsTactics::Default,
+                    maybe_comment_span.unwrap(),
+                    true,
+                )?;
+            }
 
             if let Some(block) = else_block {
                 let else_kw_span = init.span.between(block.span);

tests/source/issue-6246.rs

@@ -0,0 +1,9 @@
+fn main() {
+    let foo = 
+    // 114514
+    if true {
+        1919
+    } else {
+        810
+    };
+}

tests/target/issue-6246.rs

@@ -0,0 +1,5 @@
+fn main() {
+    let foo =
+        // 114514
+        if true { 1919 } else { 810 };
+}