checker: disallow implicit conversion from fixed array to fooptr (#8823)

vlib/math/big/big.v

@@ -147,9 +147,13 @@ pub fn (n Number) str() string {
 // .hexstr returns a hexadecimal representation of the bignum `n`
 pub fn (n Number) hexstr() string {
 	mut buf := [8192]byte{}
-	// NB: C.bignum_to_string(), returns the HEXADECIMAL representation of the bignum n
-	C.bignum_to_string(&n, buf, 8192)
-	s := unsafe { tos_clone(buf) }
+	mut s := ''
+	unsafe {
+		bp := &buf[0]
+		// NB: C.bignum_to_string(), returns the HEXADECIMAL representation of the bignum n
+		C.bignum_to_string(&n, bp, 8192)
+		s = tos_clone(bp)
+	}
 	if s.len == 0 {
 		return '0'
 	}

vlib/net/http/backend_nix.c.v

@@ -41,20 +41,21 @@ fn (req &Request) ssl_do(port int, method Method, host_name string, path string)
 	C.BIO_puts(web, req_headers.str)
 	mut content := strings.new_builder(100)
 	mut buff := [bufsize]byte{}
+	bp := &buff[0]
 	mut readcounter := 0
 	for {
 		readcounter++
-		len := unsafe { C.BIO_read(web, buff, bufsize) }
+		len := unsafe { C.BIO_read(web, bp, bufsize) }
 		if len <= 0 {
 			break
 		}
 		$if debug_http ? {
 			eprintln('ssl_do, read ${readcounter:4d} | len: $len')
 			eprintln('-'.repeat(20))
-			eprintln(unsafe { tos(buff, len) })
+			eprintln(unsafe { tos(bp, len) })
 			eprintln('-'.repeat(20))
 		}
-		unsafe { content.write_bytes(buff, len) }
+		unsafe { content.write_bytes(bp, len) }
 	}
 	if web != 0 {
 		C.BIO_free_all(web)

vlib/os/os_windows.c.v

@@ -276,7 +276,7 @@ pub fn exec(cmd string) ?Result {
 		mut result := false
 		unsafe {
 			result = C.ReadFile(child_stdout_read, buf, 1000, voidptr(&bytes_read), 0)
-			read_data.write_bytes(buf, int(bytes_read))
+			read_data.write_bytes(&buf[0], int(bytes_read))
 		}
 		if result == false || int(bytes_read) == 0 {
 			break

vlib/v/checker/check_types.v

@@ -46,13 +46,6 @@ pub fn (mut c Checker) check_basic(got table.Type, expected table.Type) bool {
 			return true
 		}
 	}
-	// e.g. [4096]byte vs byteptr
-	if got_sym.kind == .array_fixed {
-		info := got_sym.info as table.ArrayFixed
-		if c.table.type_to_str(info.elem_type) == c.table.type_to_str(expected).trim('ptr') {
-			return true
-		}
-	}
 	if exp_sym.kind in [.voidptr, .any] || got_sym.kind in [.voidptr, .any] {
 		return true
 	}

vlib/v/checker/tests/fixed_array_conv.out

@@ -0,0 +1,18 @@
+vlib/v/checker/tests/fixed_array_conv.vv:3:3: error: mismatched types `voidptr` and `[2]int`
+    1 | arr := [2,3]!
+    2 | mut p := voidptr(0)
+    3 | p = arr
+      |   ^
+    4 | mut ip := &int(0)
+    5 | ip = arr
+vlib/v/checker/tests/fixed_array_conv.vv:5:4: error: mismatched types `&int` and `[2]int`
+    3 | p = arr
+    4 | mut ip := &int(0)
+    5 | ip = arr
+      |    ^
+    6 | _ = &int(arr)
+vlib/v/checker/tests/fixed_array_conv.vv:6:6: error: cannot cast a fixed array (use e.g. `&arr[0]` instead)
+    4 | mut ip := &int(0)
+    5 | ip = arr
+    6 | _ = &int(arr)
+      |      ~~~~~~~~

vlib/v/checker/tests/fixed_array_conv.vv

@@ -0,0 +1,6 @@
+arr := [2,3]!
+mut p := voidptr(0)
+p = arr
+mut ip := &int(0)
+ip = arr
+_ = &int(arr)

vlib/v/util/util.v

@@ -30,8 +30,9 @@ pub fn vhash() string {
 	mut buf := [50]byte{}
 	buf[0] = 0
 	unsafe {
-		C.snprintf(charptr(&buf[0]), 50, '%s', C.V_COMMIT_HASH)
-		return tos_clone(buf)
+		bp := &buf[0]
+		C.snprintf(charptr(bp), 50, '%s', C.V_COMMIT_HASH)
+		return tos_clone(bp)
 	}
 }
 
@@ -98,8 +99,9 @@ pub fn githash(should_get_from_filesystem bool) string {
 	mut buf := [50]byte{}
 	buf[0] = 0
 	unsafe {
-		C.snprintf(charptr(&buf[0]), 50, '%s', C.V_CURRENT_COMMIT_HASH)
-		return tos_clone(buf)
+		bp := &buf[0]
+		C.snprintf(charptr(bp), 50, '%s', C.V_CURRENT_COMMIT_HASH)
+		return tos_clone(bp)
 	}
 }