parser: fix optional with multiple statements (#14592)

vlib/v/fmt/tests/optional_with_multi_stmts_keep.vv

@@ -0,0 +1,12 @@
+fn main() {
+	x := fmt_test() or {
+		println(err.msg())
+		-100
+	}
+	println(x)
+	assert x == -100
+}
+
+fn fmt_test() ?int {
+	return error('foo')
+}

vlib/v/parser/expr.v

@@ -443,16 +443,8 @@ pub fn (mut p Parser) expr_with_left(left ast.Expr, precedence int, is_stmt_iden
 				pos: pos
 				is_stmt: true
 			}
-		} else if p.tok.kind.is_infix() {
-			if p.tok.kind.is_prefix() && p.tok.line_nr != p.prev_tok.line_nr {
-				// return early for deref assign `*x = 2` goes to prefix expr
-				if p.tok.kind == .mul && p.peek_token(2).kind == .assign {
-					return node
-				}
-				// added 10/2020: LATER this will be parsed as PrefixExpr instead
-				p.warn_with_pos('move infix `$p.tok.kind` operator before new line (if infix intended) or use brackets for a prefix expression',
-					p.tok.pos())
-			}
+		} else if p.tok.kind.is_infix() && !(p.tok.kind in [.minus, .amp, .mul]
+			&& p.tok.line_nr != p.prev_tok.line_nr) {
 			// continue on infix expr
 			node = p.infix_expr(node)
 			// return early `if bar is SumType as b {`

vlib/v/parser/tests/prefix_first.out

@@ -1,28 +0,0 @@
-vlib/v/parser/tests/prefix_first.vv:15:3: warning: move infix `-` operator before new line (if infix intended) or use brackets for a prefix expression
-   13 |     _ = if true {
-   14 |         v = 1
-   15 |         -1
-      |         ^
-   16 |     } else {1}
-   17 |     _ = p
-vlib/v/parser/tests/prefix_first.vv:27:3: warning: move infix `&` operator before new line (if infix intended) or use brackets for a prefix expression
-   25 |     _ = opt() or {
-   26 |         _ = 1
-   27 |         &v
-      |         ^
-   28 |     }
-   29 | }
-vlib/v/parser/tests/prefix_first.vv:13:6: error: `if` expression requires an expression as the last statement of every branch
-   11 |
-   12 |     // later this should compile correctly
-   13 |     _ = if true {
-      |         ~~~~~~~
-   14 |         v = 1
-   15 |         -1
-vlib/v/parser/tests/prefix_first.vv:26:5: error: last statement in the `or {}` block should be an expression of type `&int` or exit parent scope
-   24 |     v := 3
-   25 |     _ = opt() or {
-   26 |         _ = 1
-      |           ^
-   27 |         &v
-   28 |     }

vlib/v/parser/tests/prefix_first.vv

@@ -1,29 +0,0 @@
-// a prefix op can be parsed as an infix op if there's an expression on the line before
-// https://github.com/vlang/v/pull/6491
-fn test_prefix() {
-	mut v := 1
-	mut p := &v
-	// OK, special workaround
-	unsafe {
-		v = 1
-		*p = 2
-	}
-
-	// later this should compile correctly
-	_ = if true {
-		v = 1
-		-1
-	} else {1}
-	_ = p
-}
-
-fn opt() ?&int {return none}
-
-fn test_prefix_or() {
-	// later this should compile correctly
-	v := 3
-	_ = opt() or {
-		_ = 1
-		&v
-	}
-}

vlib/v/tests/or_expr_with_multi_stmts_test.v

@@ -0,0 +1,12 @@
+fn test_or_expr_with_multi_stmts() {
+	x := fmt_test() or {
+		println(err.msg())
+		-100
+	}
+	println(x)
+	assert x == -100
+}
+
+fn fmt_test() ?int {
+	return error('foo')
+}