diff --git a/src/compat/assumptions.h b/src/compat/assumptions.h
--- a/src/compat/assumptions.h
+++ b/src/compat/assumptions.h
@@ -20,6 +20,18 @@
 #error "Bitcoin cannot be compiled without assertions."
 #endif
 
+// Assumption: We assume a C++14 (ISO/IEC 14882:2014) compiler (minimum
+//             requirement).
+// Example(s): We use std::make_unique() through the codebase.
+// Note:       MSVC does not report the expected __cplusplus value due to
+//             legacy reasons.
+#if !defined(_MSC_VER)
+// N3936* §16.8 [cpp.predefined]/p1::
+// "The name __cplusplus is defined to the value 201402L when compiling a C++
+//  translation unit."
+static_assert(__cplusplus >= 201402L, "C++14 standard assumed");
+#endif
+
 // Assumption: We assume the floating-point types to fulfill the requirements of
 //             IEC 559 (IEEE 754) standard.
 // Example(s): Floating-point division by zero in ConnectBlock,
@@ -57,8 +69,16 @@
 static_assert(std::is_same<uint8_t, unsigned char>::value,
               "uint8_t is an alias of unsigned char");
 
+// Assumption: We assume size_t to be 32-bit or 64-bit.
+// Example(s): size_t assumed to be at least 32-bit in
+//             ecdsa_signature_parse_der_lax(...).
+//             size_t assumed to be 32-bit or 64-bit in MallocUsage(...).
+static_assert(sizeof(size_t) == 4 || sizeof(size_t) == 8,
+              "size_t assumed to be 32-bit or 64-bit");
+static_assert(sizeof(size_t) == sizeof(void *),
+              "Sizes of size_t and void* assumed to be equal");
+
 // Some important things we are NOT assuming (non-exhaustive list):
-// * We are NOT assuming a specific value for sizeof(std::size_t).
 // * We are NOT assuming a specific value for std::endian::native.
 // * We are NOT assuming a specific value for std::locale("").name().
 // * We are NOT assuming a specific value for