checker: error if right side of infix is void (fix #23976) (#24001)

Author: Delta456

vlib/v/checker/check_types.v

@@ -710,6 +710,10 @@ fn (mut c Checker) promote(left_type ast.Type, right_type ast.Type) ast.Type {
 	} else if left_type.has_flag(.option) != right_type.has_flag(.option) {
 		// incompatible
 		return ast.void_type
+	} else if (left_type == ast.void_type && right_type != ast.void_type)
+		|| (right_type == ast.void_type && left_type != ast.void_type) {
+		// incompatible as well
+		return ast.void_type
 	} else {
 		return left_type // default to left if not automatic promotion possible
 	}

vlib/v/checker/tests/infix_err.out

@@ -45,45 +45,45 @@ vlib/v/checker/tests/infix_err.vv:13:7: error: `+` cannot be used with `?int`
    12 | 
    13 | _ = 4 + g()
       |       ^
-   14 | _ = int(0) + g() // FIXME: not detected
+   14 | _ = int(0) + g()
    15 | _ = g() + int(3)
 vlib/v/checker/tests/infix_err.vv:13:9: error: unwrapped Option cannot be used in an infix expression
    11 | _ = f() + f()
    12 | 
    13 | _ = 4 + g()
       |         ~~~
-   14 | _ = int(0) + g() // FIXME: not detected
+   14 | _ = int(0) + g()
    15 | _ = g() + int(3)
 vlib/v/checker/tests/infix_err.vv:14:14: error: unwrapped Option cannot be used in an infix expression
    12 | 
    13 | _ = 4 + g()
-   14 | _ = int(0) + g() // FIXME: not detected
+   14 | _ = int(0) + g()
       |              ~~~
    15 | _ = g() + int(3)
    16 | _ = g() + 3
 vlib/v/checker/tests/infix_err.vv:15:9: error: `+` cannot be used with `?int`
    13 | _ = 4 + g()
-   14 | _ = int(0) + g() // FIXME: not detected
+   14 | _ = int(0) + g()
    15 | _ = g() + int(3)
       |         ^
    16 | _ = g() + 3
    17 |
 vlib/v/checker/tests/infix_err.vv:15:5: error: unwrapped Option cannot be used in an infix expression
    13 | _ = 4 + g()
-   14 | _ = int(0) + g() // FIXME: not detected
+   14 | _ = int(0) + g()
    15 | _ = g() + int(3)
       |     ~~~
    16 | _ = g() + 3
    17 |
 vlib/v/checker/tests/infix_err.vv:16:9: error: `+` cannot be used with `?int`
-   14 | _ = int(0) + g() // FIXME: not detected
+   14 | _ = int(0) + g()
    15 | _ = g() + int(3)
    16 | _ = g() + 3
       |         ^
    17 | 
    18 | // binary operands
 vlib/v/checker/tests/infix_err.vv:16:5: error: unwrapped Option cannot be used in an infix expression
-   14 | _ = int(0) + g() // FIXME: not detected
+   14 | _ = int(0) + g()
    15 | _ = g() + int(3)
    16 | _ = g() + 3
       |     ~~~
@@ -123,8 +123,15 @@ vlib/v/checker/tests/infix_err.vv:23:22: error: ambiguous boolean expression. us
    23 | _ = 1 == 1 && 2 == 2 || 3 == 3
       |                      ~~
    24 | _ = 1 == 1 && 2 == 2 || 3 == 3 && 4 == 4
+   25 | _ = 1 + println('')
 vlib/v/checker/tests/infix_err.vv:24:22: error: ambiguous boolean expression. use `()` to ensure correct order of operations
    22 | // boolean expressions
    23 | _ = 1 == 1 && 2 == 2 || 3 == 3
    24 | _ = 1 == 1 && 2 == 2 || 3 == 3 && 4 == 4
       |                      ~~
+   25 | _ = 1 + println('')
+vlib/v/checker/tests/infix_err.vv:25:5: error: mismatched types `int literal` and `void`
+   23 | _ = 1 == 1 && 2 == 2 || 3 == 3
+   24 | _ = 1 == 1 && 2 == 2 || 3 == 3 && 4 == 4
+   25 | _ = 1 + println('')
+      |     ~~~~~~~~~~~~~~~

vlib/v/checker/tests/infix_err.vv

@@ -11,7 +11,7 @@ _ = f() + ''
 _ = f() + f()
 
 _ = 4 + g()
-_ = int(0) + g() // FIXME: not detected
+_ = int(0) + g()
 _ = g() + int(3)
 _ = g() + 3
 
@@ -22,3 +22,4 @@ _ = true || 2
 // boolean expressions
 _ = 1 == 1 && 2 == 2 || 3 == 3
 _ = 1 == 1 && 2 == 2 || 3 == 3 && 4 == 4
+_ = 1 + println('')

vlib/v/checker/tests/misspelled_mod_const_should_have_suggestion.out

@@ -4,6 +4,11 @@ Did you mean `time.second`?
     2 | 
     3 | time.sleep(1 * time.secondz)
       |                     ~~~~~~~
+vlib/v/checker/tests/misspelled_mod_const_should_have_suggestion.vv:3:12: error: mismatched types `int literal` and `void`
+    1 | import time
+    2 | 
+    3 | time.sleep(1 * time.secondz)
+      |            ~~~~~~~~~~~~~~~~
 vlib/v/checker/tests/misspelled_mod_const_should_have_suggestion.vv:3:12: error: `1 * time.secondz` (no value) used as value in argument 1 to `time.sleep`
     1 | import time
     2 |