parser: advanced division by zero check (#5629)

vlib/v/checker/checker.v

@@ -547,14 +547,6 @@ pub fn (mut c Checker) infix_expr(mut infix_expr ast.InfixExpr) table.Type {
 						}
 					}
 				}
-				if infix_expr.op in [.div, .mod] {
-					if (infix_expr.right is ast.IntegerLiteral &&
-						infix_expr.right.str() == '0') ||
-						(infix_expr.right is ast.FloatLiteral && infix_expr.right.str().f64() == 0.0) {
-						oper := if infix_expr.op == .div { 'division' } else { 'modulo' }
-						c.error('$oper by zero', right_pos)
-					}
-				}
 				return_type = promoted_type
 			}
 		}

vlib/v/parser/pratt.v

@@ -239,6 +239,28 @@ fn (mut p Parser) infix_expr(left ast.Expr) ast.Expr {
 		p.expecting_type = true
 	}
 	right = p.expr(precedence)
+
+	if op in [.div, .mod] {
+		oper := if op == .div { 'division' } else { 'modulo' }
+		match right {
+			ast.FloatLiteral {
+				if it.val.f64() == 0.0 {
+					p.error_with_pos('$oper by zero', right.pos)
+				}
+			}
+			ast.Ident {
+				if p.is_var_zero(right.name) {
+					p.error_with_pos('$oper by zero', right.pos)
+				}
+			}
+			ast.IntegerLiteral {
+				if it.val.int() == 0 {
+					p.error_with_pos('$oper by zero', right.pos)
+				}
+			}
+			else {}
+		}
+	}
 	return ast.InfixExpr{
 		left: left
 		right: right
@@ -247,6 +269,26 @@ fn (mut p Parser) infix_expr(left ast.Expr) ast.Expr {
 	}
 }
 
+fn (mut p Parser) is_var_zero(name string) bool {
+	var := p.scope.find_var(name) or {
+		return false
+	}
+	match var.expr {
+		ast.FloatLiteral {
+			if it.val.f64() == 0.0 {
+				return true
+			}
+		}
+		ast.IntegerLiteral {
+			if it.val.int() == 0 {
+				return true
+			}
+		}
+		else {}
+	}
+	return false
+}
+
 fn (mut p Parser) prefix_expr() ast.PrefixExpr {
 	pos := p.tok.position()
 	op := p.tok.kind

vlib/v/parser/tests/division_by_zero_0b0_err.out

@@ -0,0 +1,5 @@
+vlib/v/parser/tests/division_by_zero_0b0_err.v:2:12: error: division by zero
+    1 | fn main() {
+    2 |     println(1/0b0)
+      |               ~~~
+    3 | }

vlib/v/parser/tests/division_by_zero_0b0_err.vv

@@ -0,0 +1,3 @@
+fn main() {
+	println(1/0b0)
+}

vlib/v/parser/tests/division_by_zero_0x0_err.out

@@ -0,0 +1,5 @@
+vlib/v/parser/tests/division_by_zero_0x0_err.v:2:12: error: division by zero
+    1 | fn main() {
+    2 |     println(1/0x0)
+      |               ~~~
+    3 | }

vlib/v/parser/tests/division_by_zero_0x0_err.vv

@@ -0,0 +1,3 @@
+fn main() {
+	println(1/0x0)
+}

vlib/v/parser/tests/division_by_zero_0x0_var_err.out

@@ -0,0 +1,6 @@
+vlib/v/parser/tests/division_by_zero_0x0_var_err.v:3:12: error: division by zero
+    1 | fn main() {
+    2 |     a := 0x0
+    3 |     println(1/a)
+      |               ^
+    4 | }

vlib/v/parser/tests/division_by_zero_0x0_var_err.vv

@@ -0,0 +1,4 @@
+fn main() {
+	a := 0x0
+	println(1/a)
+}

vlib/v/parser/tests/division_by_zero_float_err.out

@@ -1,4 +1,4 @@
-vlib/v/checker/tests/division_by_zero_float_err.v:2:14: error: division by zero
+vlib/v/parser/tests/division_by_zero_float_err.v:2:14: error: division by zero
     1 | fn main() {
     2 |     println(1.0/0.0)
       |                 ~~~

vlib/v/parser/tests/division_by_zero_float_var_err.out

@@ -0,0 +1,6 @@
+vlib/v/parser/tests/division_by_zero_float_var_err.v:3:14: error: division by zero
+    1 | fn main() {
+    2 |     a := 0.0
+    3 |     println(1.0/a)
+      |                 ^
+    4 | }

vlib/v/parser/tests/division_by_zero_float_var_err.vv

@@ -0,0 +1,4 @@
+fn main() {
+	a := 0.0
+	println(1.0/a)
+}

vlib/v/parser/tests/division_by_zero_int_err.out

@@ -1,4 +1,4 @@
-vlib/v/checker/tests/division_by_zero_int_err.v:2:12: error: division by zero
+vlib/v/parser/tests/division_by_zero_int_err.v:2:12: error: division by zero
     1 | fn main() {
     2 |     println(1/0)
       |               ^

vlib/v/parser/tests/division_by_zero_int_var_err.out

@@ -0,0 +1,6 @@
+vlib/v/parser/tests/division_by_zero_int_var_err.v:3:12: error: division by zero
+    1 | fn main() {
+    2 |     a := 0
+    3 |     println(1/a)
+      |               ^
+    4 | }

vlib/v/parser/tests/division_by_zero_int_var_err.vv

@@ -0,0 +1,4 @@
+fn main() {
+	a := 0
+	println(1/a)
+}