diff --git a/Sources/Rules.swift b/Sources/Rules.swift
index 66ed607aa..60c05367c 100644
--- a/Sources/Rules.swift
+++ b/Sources/Rules.swift
@@ -6566,10 +6566,10 @@ public struct _FormatRules {
         options: ["someany"]
     ) { formatter in
         formatter.forEach(.keyword) { keywordIndex, keyword in
-            guard // Apply this rule to any function-like declaration
-                ["func", "init", "subscript"].contains(keyword.string),
-                // Opaque generic parameter syntax is only supported in Swift 5.7+
+            guard // Opaque generic parameter syntax is only supported in Swift 5.7+
                 formatter.options.swiftVersion >= "5.7",
+                // Apply this rule to any function-like declaration
+                [.keyword("func"), .keyword("init"), .keyword("subscript")].contains(keyword),
                 // Validate that this is a generic method using angle bracket syntax,
                 // and find the indices for all of the key tokens
                 let paramListStartIndex = formatter.index(of: .startOfScope("("), after: keywordIndex),
@@ -6579,7 +6579,9 @@ public struct _FormatRules {
                 genericSignatureStartIndex < paramListStartIndex,
                 genericSignatureEndIndex < paramListStartIndex,
                 let openBraceIndex = formatter.index(of: .startOfScope("{"), after: paramListEndIndex),
-                let closeBraceIndex = formatter.endOfScope(at: openBraceIndex)
+                let closeBraceIndex = formatter.endOfScope(at: openBraceIndex),
+                // Ignore anything with attributes
+                !formatter.modifiersForDeclaration(at: keywordIndex, contains: { $1.hasPrefix("@") })
             else { return }
 
             var genericTypes = [Formatter.GenericType]()
diff --git a/Tests/RulesTests+Syntax.swift b/Tests/RulesTests+Syntax.swift
index 01e9f06c0..0b85ddbc4 100644
--- a/Tests/RulesTests+Syntax.swift
+++ b/Tests/RulesTests+Syntax.swift
@@ -2856,6 +2856,17 @@ class SyntaxTests: RulesTests {
         testFormatting(for: input, rule: FormatRules.opaqueGenericParameters, options: options)
     }
 
+    func testIssue1684() {
+        let input = """
+        @_specialize(where S == Int)
+        func foo<S: Sequence<Element>>(t: S) {
+            print(t)
+        }
+        """
+        let options = FormatOptions(swiftVersion: "5.7")
+        testFormatting(for: input, rule: FormatRules.opaqueGenericParameters, options: options)
+    }
+
     // MARK: - genericExtensions
 
     func testGenericExtensionNotModifiedBeforeSwift5_7() {