diff --git a/lld/ELF/Symbols.h b/lld/ELF/Symbols.h
--- a/lld/ELF/Symbols.h
+++ b/lld/ELF/Symbols.h
@@ -483,11 +483,6 @@
   alignas(LazyObject) char e[sizeof(LazyObject)];
 };
 
-// It is important to keep the size of SymbolUnion small for performance and
-// memory usage reasons. 64 bytes is a soft limit based on the size of Defined
-// on a 64-bit system.
-static_assert(sizeof(SymbolUnion) <= 64, "SymbolUnion too large");
-
 template <typename T> struct AssertSymbol {
   static_assert(std::is_trivially_destructible<T>(),
                 "Symbol types must be trivially destructible");
diff --git a/lld/ELF/Symbols.cpp b/lld/ELF/Symbols.cpp
--- a/lld/ELF/Symbols.cpp
+++ b/lld/ELF/Symbols.cpp
@@ -24,6 +24,11 @@
 using namespace lld;
 using namespace lld::elf;
 
+// It is important to keep the size of SymbolUnion small for performance and
+// memory usage reasons. 64 bytes is a soft limit based on the size of Defined
+// on a 64-bit system.
+static_assert(sizeof(SymbolUnion) <= 64, "SymbolUnion too large");
+
 std::string lld::toString(const elf::Symbol &sym) {
   StringRef name = sym.getName();
   std::string ret = demangle(name, config->demangle);