diff --git a/lib/decompress/zstd_decompress_block.c b/lib/decompress/zstd_decompress_block.c
index ad3b3d8d..e93d6feb 100644
--- a/lib/decompress/zstd_decompress_block.c
+++ b/lib/decompress/zstd_decompress_block.c
@@ -948,7 +948,7 @@ ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e longOffsets, c
 }
 
 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
-static int ZSTD_dictionaryIsActive(ZSTD_DCtx const* dctx, BYTE const* prefixStart, BYTE const* oLitEnd)
+MEM_STATIC int ZSTD_dictionaryIsActive(ZSTD_DCtx const* dctx, BYTE const* prefixStart, BYTE const* oLitEnd)
 {
     size_t const windowSize = dctx->fParams.windowSize;
     /* No dictionary used. */
@@ -969,6 +969,7 @@ MEM_STATIC void ZSTD_assertValidSequence(
         seq_t const seq,
         BYTE const* prefixStart, BYTE const* virtualStart)
 {
+#if DEBUGLEVEL >= 1
     size_t const windowSize = dctx->fParams.windowSize;
     size_t const sequenceSize = seq.litLength + seq.matchLength;
     BYTE const* const oLitEnd = op + seq.litLength;
@@ -986,6 +987,9 @@ MEM_STATIC void ZSTD_assertValidSequence(
         /* Offset must be within our window. */
         assert(seq.offset <= windowSize);
     }
+#else
+    (void)dctx, (void)op, (void)oend, (void)seq, (void)prefixStart, (void)virtualStart;
+#endif
 }
 #endif