diff --git a/mlir/include/mlir-c/IR.h b/mlir/include/mlir-c/IR.h
--- a/mlir/include/mlir-c/IR.h
+++ b/mlir/include/mlir-c/IR.h
@@ -713,9 +713,7 @@
 //===----------------------------------------------------------------------===//
 
 /// Checks whether a type id is null.
-MLIR_CAPI_EXPORTED static inline bool mlirTypeIDIsNull(MlirTypeID typeID) {
-  return !typeID.ptr;
-}
+static inline bool mlirTypeIDIsNull(MlirTypeID typeID) { return !typeID.ptr; }
 
 /// Checks if two type ids are equal.
 MLIR_CAPI_EXPORTED bool mlirTypeIDEqual(MlirTypeID typeID1, MlirTypeID typeID2);
diff --git a/mlir/lib/CAPI/IR/IR.cpp b/mlir/lib/CAPI/IR/IR.cpp
--- a/mlir/lib/CAPI/IR/IR.cpp
+++ b/mlir/lib/CAPI/IR/IR.cpp
@@ -36,6 +36,8 @@
   return wrap(context);
 }
 
+bool mlirTypeIDIsNull(MlirTypeID typeID) { return !typeID.ptr; }
+
 bool mlirContextEqual(MlirContext ctx1, MlirContext ctx2) {
   return unwrap(ctx1) == unwrap(ctx2);
 }