diff --git a/src/util.cpp b/src/util.cpp
index 65b1fe3082..13bfbbcd47 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -18,17 +18,10 @@ void zig_panic(const char *format, ...) {
     vfprintf(stderr, format, ap);
     fflush(stderr);
     va_end(ap);
-    stage2_panic(nullptr, 0);
+    stage2_panic("", 0);
     abort();
 }
 
-void assert(bool ok) {
-    if (!ok) {
-        const char *msg = "Assertion failed. This is a bug in the Zig compiler.";
-        stage2_panic(msg, strlen(msg));
-    }
-}
-
 uint32_t int_hash(int i) {
     return (uint32_t)(i % UINT32_MAX);
 }
diff --git a/src/util.hpp b/src/util.hpp
index 1248635de9..8abcef32ce 100644
--- a/src/util.hpp
+++ b/src/util.hpp
@@ -43,15 +43,21 @@ ATTRIBUTE_NORETURN
 ATTRIBUTE_PRINTF(1, 2)
 void zig_panic(const char *format, ...);
 
+static inline void zig_assert(bool ok, const char *file, int line, const char *func) {
+    if (!ok) {
+        zig_panic("Assertion failed at %s:%d in %s. This is a bug in the Zig compiler.", file, line, func);
+    }
+}
+
 #ifdef _WIN32
 #define __func__ __FUNCTION__
 #endif
 
-#define zig_unreachable() zig_panic("unreachable: %s:%s:%d", __FILE__, __func__, __LINE__)
+#define zig_unreachable() zig_panic("Unreachable at %s:%d in %s. This is a bug in the Zig compiler.", __FILE__, __LINE__, __func__)
 
 // Assertions in stage1 are always on, and they call zig @panic.
 #undef assert
-void assert(bool ok);
+#define assert(ok) zig_assert(ok, __FILE__, __LINE__, __func__)
 
 #if defined(_MSC_VER)
 static inline int clzll(unsigned long long mask) {