From d15d13674cc32e31c126cf21f3b9f87d32775d47 Mon Sep 17 00:00:00 2001
From: Nick Treleaven <n@trelsoft.com>
Date: Fri, 1 Jan 2021 13:38:11 +0000
Subject: [PATCH] parser: parse non-identifier expressions for sizeof too
 (#7781)

---
 vlib/v/parser/pratt.v      |  8 +++++---
 vlib/v/tests/sizeof_test.v | 13 ++++++++++++-
 vlib/v/token/token.v       | 11 +++++++++++
 3 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/vlib/v/parser/pratt.v b/vlib/v/parser/pratt.v
index 84aac03b51..c19ab55133 100644
--- a/vlib/v/parser/pratt.v
+++ b/vlib/v/parser/pratt.v
@@ -142,9 +142,11 @@ pub fn (mut p Parser) expr(precedence int) ast.Expr {
 			pos := p.tok.position()
 			p.next() // sizeof
 			p.check(.lpar)
-			is_known_var := p.mark_var_as_used(p.tok.lit)
-			if is_known_var {
-				expr := p.parse_ident(table.Language.v)
+			if !p.tok.can_start_type(table.builtin_type_names) {
+				if p.tok.kind == .name {
+					p.mark_var_as_used(p.tok.lit)
+				}
+				expr := p.expr(0)
 				node = ast.SizeOf{
 					is_type: false
 					expr: expr
diff --git a/vlib/v/tests/sizeof_test.v b/vlib/v/tests/sizeof_test.v
index bea1d39360..372f13250b 100644
--- a/vlib/v/tests/sizeof_test.v
+++ b/vlib/v/tests/sizeof_test.v
@@ -1,6 +1,17 @@
 import math
 
-fn test_sizeof() {
+struct S1 {
+	i voidptr
+}
+
+fn test_math_sizeof() {
 	r := math.f32_from_bits(sizeof(int))
 	assert r > 5.6e-45 && r < 5.7e-45
 }
+
+fn test_sizeof() {
+	// depends on compiler
+	assert sizeof(`€`) in [u32(2), 4]
+	// depends on -m32/64
+	assert sizeof(S1) in [u32(4), 8]
+}
diff --git a/vlib/v/token/token.v b/vlib/v/token/token.v
index 0646ce1e38..8bf8f4fadc 100644
--- a/vlib/v/token/token.v
+++ b/vlib/v/token/token.v
@@ -431,3 +431,14 @@ pub fn (kind Kind) is_infix() bool {
 	return kind in
 		[.plus, .minus, .mod, .mul, .div, .eq, .ne, .gt, .lt, .key_in, /*  */.key_as, .ge, .le, .logical_or, .xor, .not_in, .key_is, .not_is, /*  */.and, .dot, .pipe, .amp, .left_shift, .right_shift, .arrow]
 }
+
+// Pass table.builtin_type_names
+// Note: can't import table here due to circular module dependency
+pub fn (tok &Token) can_start_type(builtin_type_names []string) bool {
+	match tok.kind {
+		.name { return tok.lit[0].is_capital() || tok.lit in builtin_type_names }
+		.amp, .lsbr, .question { return true }
+		else {}
+	}
+	return false
+}