diff --git a/test/std/containers/views/span.cons/assign.pass.cpp b/test/std/containers/views/span.cons/assign.pass.cpp
index 3f8d5f4..d308695 100644
--- a/test/std/containers/views/span.cons/assign.pass.cpp
+++ b/test/std/containers/views/span.cons/assign.pass.cpp
@@ -55,18 +55,18 @@
 //      On darwin i386, ptrdiff_t is the same as int.
         constexpr std::span<const int> spans[] = {
             {},
-            {carr1, static_cast<std::ptrdiff_t>(0)},
-            {carr1,     1},
-            {carr1,     2},
-            {carr1,     3},
-            {carr1,     4},
-            {carr2, static_cast<std::ptrdiff_t>(0)},
-            {carr2,     1},
-            {carr2,     2},
-            {carr2,     3},
-            {carr3, static_cast<std::ptrdiff_t>(0)},
-            {carr3,     1},
-            {carr3,     2}
+            {carr1, static_cast<std::size_t>(0)},
+            {carr1,     1U},
+            {carr1,     2U},
+            {carr1,     3U},
+            {carr1,     4U},
+            {carr2, static_cast<std::size_t>(0)},
+            {carr2,     1U},
+            {carr2,     2U},
+            {carr2,     3U},
+            {carr3, static_cast<std::size_t>(0)},
+            {carr3,     1U},
+            {carr3,     2U}
             };
 
         static_assert(std::size(spans) == 13, "" );
diff --git a/test/std/containers/views/span.iterators/begin.pass.cpp b/test/std/containers/views/span.iterators/begin.pass.cpp
index e4532ad..c931f1f 100644
--- a/test/std/containers/views/span.iterators/begin.pass.cpp
+++ b/test/std/containers/views/span.iterators/begin.pass.cpp
@@ -110,7 +110,7 @@
     testRuntimeSpan(std::span<int>(iArr2, 5));
 
     std::string s;
-    testRuntimeSpan(std::span<std::string>(&s, (std::ptrdiff_t) 0));
+    testRuntimeSpan(std::span<std::string>(&s, (std::size_t) 0));
     testRuntimeSpan(std::span<std::string>(&s, 1));
 
   return 0;
diff --git a/test/std/containers/views/span.iterators/end.pass.cpp b/test/std/containers/views/span.iterators/end.pass.cpp
index 707ec88..2dcb1df 100644
--- a/test/std/containers/views/span.iterators/end.pass.cpp
+++ b/test/std/containers/views/span.iterators/end.pass.cpp
@@ -118,7 +118,7 @@
     testRuntimeSpan(std::span<int>(iArr2, 5));
 
     std::string s;
-    testRuntimeSpan(std::span<std::string>(&s, (std::ptrdiff_t) 0));
+    testRuntimeSpan(std::span<std::string>(&s, (std::size_t) 0));
     testRuntimeSpan(std::span<std::string>(&s, 1));
 
   return 0;
diff --git a/test/std/containers/views/span.iterators/rbegin.pass.cpp b/test/std/containers/views/span.iterators/rbegin.pass.cpp
index fc7d3c8..797629a 100644
--- a/test/std/containers/views/span.iterators/rbegin.pass.cpp
+++ b/test/std/containers/views/span.iterators/rbegin.pass.cpp
@@ -111,7 +111,7 @@
     testRuntimeSpan(std::span<int>(iArr2, 5));
 
     std::string s;
-    testRuntimeSpan(std::span<std::string>(&s, static_cast<std::ptrdiff_t>(0)));
+    testRuntimeSpan(std::span<std::string>(&s, static_cast<std::size_t>(0)));
     testRuntimeSpan(std::span<std::string>(&s, 1));
 
   return 0;
diff --git a/test/std/containers/views/span.iterators/rend.pass.cpp b/test/std/containers/views/span.iterators/rend.pass.cpp
index 23d09d5..077ee8d 100644
--- a/test/std/containers/views/span.iterators/rend.pass.cpp
+++ b/test/std/containers/views/span.iterators/rend.pass.cpp
@@ -112,7 +112,7 @@
     testRuntimeSpan(std::span<int>(iArr2, 5));
 
     std::string s;
-    testRuntimeSpan(std::span<std::string>(&s, (std::ptrdiff_t) 0));
+    testRuntimeSpan(std::span<std::string>(&s, (std::size_t) 0));
     testRuntimeSpan(std::span<std::string>(&s, 1));
 
   return 0;
diff --git a/test/std/containers/views/span.objectrep/as_bytes.pass.cpp b/test/std/containers/views/span.objectrep/as_bytes.pass.cpp
index 3e6a7d7..12772c4 100644
--- a/test/std/containers/views/span.objectrep/as_bytes.pass.cpp
+++ b/test/std/containers/views/span.objectrep/as_bytes.pass.cpp
@@ -72,7 +72,7 @@
     testRuntimeSpan(std::span<int, 5>(iArr2 + 1, 5));
 
     std::string s;
-    testRuntimeSpan(std::span<std::string>(&s, (std::ptrdiff_t) 0));
+    testRuntimeSpan(std::span<std::string>(&s, (std::size_t) 0));
     testRuntimeSpan(std::span<std::string>(&s, 1));
 
   return 0;
diff --git a/test/std/containers/views/span.objectrep/as_writeable_bytes.fail.cpp b/test/std/containers/views/span.objectrep/as_writeable_bytes.fail.cpp
index b987edb..9dadedd 100644
--- a/test/std/containers/views/span.objectrep/as_writeable_bytes.fail.cpp
+++ b/test/std/containers/views/span.objectrep/as_writeable_bytes.fail.cpp
@@ -40,7 +40,7 @@
     std::as_writeable_bytes(std::span<const long, 0>());        // expected-error {{no matching function for call to 'as_writeable_bytes'}}
     std::as_writeable_bytes(std::span<const double, 0>());      // expected-error {{no matching function for call to 'as_writeable_bytes'}}
     std::as_writeable_bytes(std::span<const A, 0>());           // expected-error {{no matching function for call to 'as_writeable_bytes'}}
-    std::as_writeable_bytes(std::span<const std::string, 0>()); // expected-error {{no matching function for call to 'as_writeable_bytes'}}
+    std::as_writeable_bytes(std::span<const std::string, (size_t)0>()); // expected-error {{no matching function for call to 'as_writeable_bytes'}}
 
     std::as_writeable_bytes(std::span<const int>   (iArr2, 1));     // expected-error {{no matching function for call to 'as_writeable_bytes'}}
     std::as_writeable_bytes(std::span<const int, 1>(iArr2 + 5, 1)); // expected-error {{no matching function for call to 'as_writeable_bytes'}}
diff --git a/test/std/containers/views/span.objectrep/as_writeable_bytes.pass.cpp b/test/std/containers/views/span.objectrep/as_writeable_bytes.pass.cpp
index 96bb40e..b12500d 100644
--- a/test/std/containers/views/span.objectrep/as_writeable_bytes.pass.cpp
+++ b/test/std/containers/views/span.objectrep/as_writeable_bytes.pass.cpp
@@ -72,7 +72,7 @@
     testRuntimeSpan(std::span<int, 5>(iArr2 + 1, 5));
 
     std::string s;
-    testRuntimeSpan(std::span<std::string>(&s, (std::ptrdiff_t) 0));
+    testRuntimeSpan(std::span<std::string>(&s, (std::size_t) 0));
     testRuntimeSpan(std::span<std::string>(&s, 1));
 
   return 0;
diff --git a/test/std/containers/views/span.obs/empty.pass.cpp b/test/std/containers/views/span.obs/empty.pass.cpp
index 9db8c8a..bae610c 100644
--- a/test/std/containers/views/span.obs/empty.pass.cpp
+++ b/test/std/containers/views/span.obs/empty.pass.cpp
@@ -67,7 +67,7 @@
     assert(!(std::span<int, 5>(iArr2, 5).empty()));
 
     std::string s;
-    assert( ((std::span<std::string>(&s, (std::ptrdiff_t) 0)).empty()));
+    assert( ((std::span<std::string>(&s, (std::size_t) 0)).empty()));
     assert(!((std::span<std::string>(&s, 1).empty())));
 
   return 0;
diff --git a/test/std/containers/views/span.obs/size.pass.cpp b/test/std/containers/views/span.obs/size.pass.cpp
index b5dcefd..f26a225 100644
--- a/test/std/containers/views/span.obs/size.pass.cpp
+++ b/test/std/containers/views/span.obs/size.pass.cpp
@@ -85,7 +85,7 @@
     testRuntimeSpan(std::span<int, 5>(iArr2 + 1, 5), 5);
 
     std::string s;
-    testRuntimeSpan(std::span<std::string>(&s, (std::ptrdiff_t) 0), 0);
+    testRuntimeSpan(std::span<std::string>(&s, (std::size_t) 0), 0);
     testRuntimeSpan(std::span<std::string>(&s, 1), 1);
 
   return 0;
diff --git a/test/std/containers/views/span.obs/size_bytes.pass.cpp b/test/std/containers/views/span.obs/size_bytes.pass.cpp
index 1d42352..447829d 100644
--- a/test/std/containers/views/span.obs/size_bytes.pass.cpp
+++ b/test/std/containers/views/span.obs/size_bytes.pass.cpp
@@ -86,7 +86,7 @@
     testRuntimeSpan(std::span<int, 5>(iArr2 + 1, 5), 5);
 
     std::string s;
-    testRuntimeSpan(std::span<std::string>(&s, (std::ptrdiff_t) 0), 0);
+    testRuntimeSpan(std::span<std::string>(&s, (std::size_t) 0), 0);
     testRuntimeSpan(std::span<std::string>(&s, 1), 1);
 
   return 0;