don't error for types with the same size

vlib/v/ast/types.v

@@ -374,6 +374,23 @@ pub fn (typ Type) is_unsigned() bool {
 	return typ.idx() in ast.unsigned_integer_type_idxs
 }
 
+pub fn (typ Type) flip_signedness() Type {
+	r := match typ {
+		i8_type    {byte_type}
+		i16_type   {u16_type}
+		int_type   {u32_type}
+		isize_type {usize_type}
+		i64_type   {u64_type}
+		byte_type  {i8_type}
+		u16_type   {i16_type}
+		u32_type   {int_type}
+		usize_type {isize_type}
+		u64_type   {i64_type}
+		else       {typ}
+	}
+	return r
+}
+
 [inline]
 pub fn (typ Type) is_int_literal() bool {
 	return int(typ) == ast.int_literal_type_idx

vlib/v/ast/types_test.v

@@ -79,3 +79,9 @@ fn test_derive() {
 	assert t2.has_flag(ast.TypeFlag.generic) == true
 	assert t2.nr_muls() == 10
 }
+
+fn test_flip_signedness() {
+	assert ast.i8_type.flip_signedness() == ast.byte_type
+	assert ast.u16_type.flip_signedness() == ast.i16_type
+	assert ast.isize_type.flip_signedness() == ast.usize_type
+}

vlib/v/checker/checker.v

@@ -636,7 +636,8 @@ pub fn (mut c Checker) infix_expr(mut node ast.InfixExpr) ast.Type {
 						rt := c.table.sym(right_type).name
 						c.error('negative value cannot be compared with `$rt`', node.left.pos)
 					}
-				} else if is_left_type_signed != is_right_type_signed {
+				} else if is_left_type_signed != is_right_type_signed &&
+					left_type.flip_signedness() != right_type {
 					// prevent e.g. `u16(-1) == int(-1)` which is false in C
 					if (is_right_type_signed && left_type in ast.int_promoted_type_idxs)
 						|| (is_left_type_signed && right_type in ast.int_promoted_type_idxs) {

vlib/x/ttf/render_bmp.v

@@ -778,7 +778,7 @@ pub fn (mut bmp BitMap) draw_glyph(index u16) (int, int) {
 			}
 		}
 
-		if count == glyph.contour_ends[c] {
+		if count == int(glyph.contour_ends[c]) {
 			// dprintln("count == glyph.contour_ends[count]")
 			if s == 2 { // final point was off-curve. connect to start