diff --git a/src/core/inttypes.c b/src/core/inttypes.c
index 14956b02..fad40bf8 100644
--- a/src/core/inttypes.c
+++ b/src/core/inttypes.c
@@ -256,7 +256,7 @@ static Janet cfun_it_##type##_##name(int32_t argc, Janet *argv) { \
 
 #define DIVMETHODINVERT_SIGNED(T, type, name, oper) \
 static Janet cfun_it_##type##_##name(int32_t argc, Janet *argv) { \
-    janet_arity(argc, 2, -1);                       \
+    janet_fixarity(argc, 2);                       \
     T *box = janet_abstract(&it_##type##_type, sizeof(T)); \
     *box = janet_unwrap_##type(argv[1]); \
     T value = janet_unwrap_##type(argv[0]); \
diff --git a/src/core/io.c b/src/core/io.c
index edaefef6..01948ed4 100644
--- a/src/core/io.c
+++ b/src/core/io.c
@@ -157,36 +157,6 @@ static Janet cfun_io_fopen(int32_t argc, Janet *argv) {
     return f ? makef(f, flags) : janet_wrap_nil();
 }
 
-static Janet cfun_io_fdopen(int32_t argc, Janet *argv) {
-    janet_arity(argc, 1, 2);
-    const int fd = janet_getinteger(argv, 0);
-    const uint8_t *fmode;
-    int flags;
-    if (argc == 2) {
-        fmode = janet_getkeyword(argv, 1);
-        flags = checkflags(fmode);
-    } else {
-        fmode = (const uint8_t *)"r";
-        flags = JANET_FILE_READ;
-    }
-#ifdef JANET_WINDOWS
-#define fdopen _fdopen
-#endif
-    FILE *f = fdopen(fd, (const char *)fmode);
-    return f ? makef(f, flags) : janet_wrap_nil();
-}
-
-static Janet cfun_io_fileno(int32_t argc, Janet *argv) {
-    janet_fixarity(argc, 1);
-    IOFile *iof = janet_getabstract(argv, 0, &cfun_io_filetype);
-    if (iof->flags & JANET_FILE_CLOSED)
-        janet_panic("file is closed");
-#ifdef JANET_WINDOWS
-#define fileno _fileno
-#endif
-    return janet_wrap_integer(fileno(iof->file));
-}
-
 /* Read up to n bytes into buffer. */
 static void read_chunk(IOFile *iof, JanetBuffer *buffer, int32_t nBytesMax) {
     if (!(iof->flags & (JANET_FILE_READ | JANET_FILE_UPDATE)))
@@ -338,7 +308,6 @@ static Janet cfun_io_fseek(int32_t argc, Janet *argv) {
 
 static JanetMethod io_file_methods[] = {
     {"close", cfun_io_fclose},
-    {"fileno", cfun_io_fileno},
     {"flush", cfun_io_fflush},
     {"read", cfun_io_fread},
     {"seek", cfun_io_fseek},
@@ -592,26 +561,6 @@ static const JanetReg io_cfuns[] = {
              "\tb - open the file in binary mode (rather than text mode)\n"
              "\t+ - append to the file instead of overwriting it")
     },
-    {
-        "file/fdopen", cfun_io_fdopen,
-        JDOC("(file/fdopen fd &opt mode)\n\n"
-             "Create a file from an fd. fd is a platform specific file descriptor, and "
-             "mode is a set of flags indicating the mode to open the file in. "
-             "mode is a keyword where each character represents a flag. If the file "
-             "cannot be opened, returns nil, otherwise returns the new file handle. "
-             "Mode flags:\n\n"
-             "\tr - allow reading from the file\n"
-             "\tw - allow writing to the file\n"
-             "\ta - append to the file\n"
-             "\tb - open the file in binary mode (rather than text mode)\n"
-             "\t+ - append to the file instead of overwriting it")
-    },
-    {
-        "file/fileno", cfun_io_fileno,
-        JDOC("(file/fileno f)\n\n"
-             "Return the underlying file descriptor for the file as a number."
-             "The meaning of this number is platform specific.")
-    },
     {
         "file/close", cfun_io_fclose,
         JDOC("(file/close f)\n\n"
diff --git a/src/core/vm.c b/src/core/vm.c
index c13aba23..e82b8eeb 100644
--- a/src/core/vm.c
+++ b/src/core/vm.c
@@ -195,49 +195,64 @@ JANET_THREAD_LOCAL jmp_buf *janet_vm_jmp_buf = NULL;
     }
 
 /* Trace a function call */
-static void vm_do_trace(JanetFunction *func) {
-    Janet *stack = janet_vm_fiber->data + janet_vm_fiber->stackstart;
-    int32_t start = janet_vm_fiber->stackstart;
-    int32_t end = janet_vm_fiber->stacktop;
-    int32_t argc = end - start;
-    if (func->def->name) {
+static void vm_do_trace(JanetFunction *func, int32_t argc, const Janet *argv) {
+    if (func->def->name){
         janet_printf("trace (%S", func->def->name);
     } else {
         janet_printf("trace (%p", janet_wrap_function(func));
     }
     for (int32_t i = 0; i < argc; i++) {
-        janet_printf(" %p", stack[i]);
+        janet_printf(" %p", argv[i]);
     }
-    printf(")\n");
+    janet_printf(")\n");
 }
 
-/* Call a non function type */
-static Janet call_nonfn(JanetFiber *fiber, Janet callee) {
-    int32_t argn = fiber->stacktop - fiber->stackstart;
-    Janet ds, key;
-    JanetType t = janet_type(callee);
-    if (t == JANET_ABSTRACT) {
-        JanetAbstract abst = janet_unwrap_abstract(callee);
-        const JanetAbstractType *at = janet_abstract_type(abst);
-        if (NULL != at->call) {
-            fiber->stacktop = fiber->stackstart;
-            return at->call(abst, argn, fiber->data + fiber->stackstart);
+/* Invoke a method once we have looked it up */
+static Janet janet_method_invoke(Janet method, int32_t argc, Janet *argv) {
+    switch (janet_type(method)) {
+        case JANET_CFUNCTION:
+            return (janet_unwrap_cfunction(method))(argc, argv);
+        case JANET_FUNCTION: {
+            JanetFunction *fun = janet_unwrap_function(method);
+            return janet_call(fun, argc, argv);
+        }
+        case JANET_ABSTRACT: {
+            JanetAbstract abst = janet_unwrap_abstract(method);
+            const JanetAbstractType *at = janet_abstract_type(abst);
+            if (NULL != at->call) {
+                return at->call(abst, argc, argv);
+            }
+        }
+        /* fallthrough */
+        case JANET_STRING:
+        case JANET_BUFFER:
+        case JANET_TABLE:
+        case JANET_STRUCT:
+        case JANET_ARRAY:
+        case JANET_TUPLE: {
+            if (argc != 1) {
+                janet_panicf("%v called with %d arguments, possibly expected 1", method, argc);
+            }
+            return janet_in(method, argv[0]);
+        }
+        default: {
+            if (argc != 1) {
+                janet_panicf("%v called with %d arguments, possibly expected 1", method, argc);
+            }
+            return janet_in(argv[0], method);
         }
     }
-    if (argn != 1) janet_panicf("%v called with %d arguments, possibly expected 1", callee, argn);
-    if ((1 << t) & (JANET_TFLAG_INDEXED | JANET_TFLAG_DICTIONARY |
-                    JANET_TFLAG_STRING | JANET_TFLAG_BUFFER | JANET_TFLAG_ABSTRACT)) {
-        ds = callee;
-        key = fiber->data[fiber->stackstart];
-    } else {
-        ds = fiber->data[fiber->stackstart];
-        key = callee;
-    }
-    fiber->stacktop = fiber->stackstart;
-    return janet_in(ds, key);
 }
 
-/* Get a callable from a keyword method name and check ensure that it is valid. */
+/* Call a non function type from a JOP_CALL or JOP_TAILCALL instruction.
+ * Assumes that the arguments are on the fiber stack. */
+static Janet call_nonfn(JanetFiber *fiber, Janet callee) {
+    int32_t argc = fiber->stacktop - fiber->stackstart;
+    fiber->stacktop = fiber->stackstart;
+    return janet_method_invoke(callee, argc, fiber->data + fiber->stacktop);
+}
+
+/* Get a callable from a keyword method name and ensure that it is valid. */
 static Janet resolve_method(Janet name, JanetFiber *fiber) {
     int32_t argc = fiber->stacktop - fiber->stackstart;
     if (argc < 1) janet_panicf("method call (%v) takes at least 1 argument, got 0", name);
@@ -250,36 +265,7 @@ static Janet resolve_method(Janet name, JanetFiber *fiber) {
 /* Lookup method on value x */
 static Janet janet_method_lookup(Janet x, const char *name) {
     Janet kname = janet_ckeywordv(name);
-    switch (janet_type(x)) {
-        default:
-            return janet_wrap_nil();
-        case JANET_ABSTRACT: {
-            Janet method;
-            void *abst = janet_unwrap_abstract(x);
-            JanetAbstractType *type = (JanetAbstractType *)janet_abstract_type(abst);
-            if (!type->get || !(type->get)(abst, kname, &method)) {
-                return janet_wrap_nil();
-            } else {
-                return method;
-            }
-        }
-        case JANET_TABLE:
-            return janet_table_get(janet_unwrap_table(x), kname);
-        case JANET_STRUCT:
-            return janet_struct_get(janet_unwrap_struct(x), kname);
-    }
-}
-
-/* Invoke a method once we have looked it up */
-static Janet janet_method_invoke(Janet method, int32_t argc, Janet *argv) {
-    if (janet_checktype(method, JANET_CFUNCTION)) {
-        return (janet_unwrap_cfunction(method))(argc, argv);
-    } else if (janet_checktype(method, JANET_FUNCTION)) {
-        JanetFunction *fun = janet_unwrap_function(method);
-        return janet_call(fun, argc, argv);
-    } else {
-        janet_panicf("method is not callable: %v", method);
-    }
+    return janet_get(x, kname);
 }
 
 /* Call a method first on the righthand side, and then on the left hand side with a prefix */
@@ -901,7 +887,9 @@ static JanetSignal run_vm(JanetFiber *fiber, Janet in) {
         }
         if (janet_checktype(callee, JANET_FUNCTION)) {
             func = janet_unwrap_function(callee);
-            if (func->gc.flags & JANET_FUNCFLAG_TRACE) vm_do_trace(func);
+            if (func->gc.flags & JANET_FUNCFLAG_TRACE) {
+                vm_do_trace(func, fiber->stacktop - fiber->stackstart, stack);
+            }
             janet_stack_frame(stack)->pc = pc;
             if (janet_fiber_funcframe(fiber, func)) {
                 int32_t n = fiber->stacktop - fiber->stackstart;
@@ -938,7 +926,9 @@ static JanetSignal run_vm(JanetFiber *fiber, Janet in) {
         }
         if (janet_checktype(callee, JANET_FUNCTION)) {
             func = janet_unwrap_function(callee);
-            if (func->gc.flags & JANET_FUNCFLAG_TRACE) vm_do_trace(func);
+            if (func->gc.flags & JANET_FUNCFLAG_TRACE) {
+                vm_do_trace(func, fiber->stacktop - fiber->stackstart, stack);
+            }
             if (janet_fiber_funcframe_tail(fiber, func)) {
                 janet_stack_frame(fiber->data + fiber->frame)->pc = pc;
                 int32_t n = fiber->stacktop - fiber->stackstart;
@@ -1186,6 +1176,11 @@ Janet janet_call(JanetFunction *fun, int32_t argc, const Janet *argv) {
     if (janet_vm_stackn >= JANET_RECURSION_GUARD)
         janet_panic("C stack recursed too deeply");
 
+    /* Tracing */
+    if (fun->gc.flags & JANET_FUNCFLAG_TRACE) {
+        vm_do_trace(fun, argc, argv);
+    }
+
     /* Push frame */
     janet_fiber_pushn(janet_vm_fiber, argv, argc);
     if (janet_fiber_funcframe(janet_vm_fiber, fun)) {