diff --git a/Sources/CodeGen/LLVM/Transpilation.swift b/Sources/CodeGen/LLVM/Transpilation.swift
index 4c15610ba..1309fc76d 100644
--- a/Sources/CodeGen/LLVM/Transpilation.swift
+++ b/Sources/CodeGen/LLVM/Transpilation.swift
@@ -443,6 +443,11 @@ extension LLVM.Module {
     //   setLinkage(.private, for: llvmFunction)
     // }
 
+    // Monomorphized functions always have private linkage.
+    if f.isMonomorphized {
+      setLinkage(.private, for: llvmFunction)
+    }
+
     // Functions that return `Never` have the `noreturn` attribute.
     if !m[f].isSubscript && (m[f].output == .never) {
       addAttribute(.init(.noreturn, in: &self), to: llvmFunction)
diff --git a/Sources/IR/FunctionID.swift b/Sources/IR/FunctionID.swift
index 06675d872..41e121451 100644
--- a/Sources/IR/FunctionID.swift
+++ b/Sources/IR/FunctionID.swift
@@ -61,6 +61,16 @@ extension Function {
       self.value = .monomorphized(base: base, arguments: arguments)
     }
 
+    /// `true` if `self` is the identity of a monomorphized function.
+    public var isMonomorphized: Bool {
+      switch value {
+      case .monomorphized:
+        return true
+      default:
+        return false
+      }
+    }
+
   }
 
 }