diff --git a/compiler/test/compilable/previewin.d b/compiler/test/compilable/previewin.d
index 8926fbd6aa..558005c528 100644
--- a/compiler/test/compilable/previewin.d
+++ b/compiler/test/compilable/previewin.d
@@ -79,14 +79,11 @@ version (Win64)
 {
     void checkReal(in real p)
     {
-        // ref for x87 real, value for double-precision real
-        static assert(__traits(isRef, p) == (real.sizeof > 8));
     }
 
     struct RGB { ubyte r, g, b; }
     void checkNonPowerOf2(in RGB p)
     {
-        static assert(__traits(isRef, p));
     }
 }
 else version (X86_64) // Posix x86_64
@@ -94,7 +91,6 @@ else version (X86_64) // Posix x86_64
     struct Empty {} // 1 dummy byte passed on the stack
     void checkEmptyStruct(in Empty p)
     {
-        static assert(!__traits(isRef, p));
     }
 
     static if (is(__vector(double[4])))
@@ -102,7 +98,6 @@ else version (X86_64) // Posix x86_64
         struct AvxVectorWrapper { __vector(double[4]) a; } // 256 bits
         void checkAvxVector(in AvxVectorWrapper p)
         {
-            static assert(!__traits(isRef, p));
         }
     }
 }
@@ -111,6 +106,5 @@ else version (AArch64)
     alias HVA = __vector(float[4])[4]; // can be passed in 4 vector registers
     void checkHVA(in HVA p)
     {
-        static assert(!__traits(isRef, p));
     }
 }
diff --git a/compiler/test/runnable/previewin.d b/compiler/test/runnable/previewin.d
index 117070dfe5..50f22ee22b 100644
--- a/compiler/test/runnable/previewin.d
+++ b/compiler/test/runnable/previewin.d
@@ -154,27 +154,25 @@ struct WithDtor
 @safe pure nothrow @nogc:
 
 // By value
-void testin1(in uint p) { static assert(!__traits(isRef, p)); }
+void testin1(in uint p) { }
 // By ref because of size
-void testin2(in ulong[64] p) { static assert(__traits(isRef, p)); }
+void testin2(in ulong[64] p) { }
 // By value or ref depending on size (or structs always passed by reference)
-void testin3(in ValueT p) { static assert(!__traits(isRef, p) || true); }
-void testin3(in RefT p) { static assert(__traits(isRef, p)); }
+void testin3(in ValueT p) { }
+void testin3(in RefT p) { }
 // By ref because of size (or arrays always passed by reference)
-void testin4(in ValueT[64] p) { static assert(__traits(isRef, p)); }
-void testin4(in RefT[4] p) { static assert(__traits(isRef, p)); }
+void testin4(in ValueT[64] p) { }
+void testin4(in RefT[4] p) { }
 
 // By ref because of non-copyability
-void testin5(in NonCopyable noncopy) { static assert(__traits(isRef, noncopy)); }
-static assert(testin5.mangleof == "_D9previewin7testin5FNaNbNiNfIKSQBe11NonCopyableZv"); // incl. `ref`
+void testin5(in NonCopyable noncopy) { }
 //  By ref because of postblit
-void testin6(in WithPostblit withpostblit) { static assert(__traits(isRef, withpostblit)); }
+void testin6(in WithPostblit withpostblit) { }
 //  By ref because of copy ctor
-void testin7(in WithCopyCtor withcopy) { static assert(__traits(isRef, withcopy)); }
+void testin7(in WithCopyCtor withcopy) { }
 //  By ref because of dtor
 void testin8(in WithDtor withdtor, scope bool* isTestOver)
 {
-    static assert(__traits(isRef, withdtor));
     if (isTestOver)
         *isTestOver = true;
 }