From e70bde54dc143747d716946d674f6bcad99eaa1c Mon Sep 17 00:00:00 2001
From: Delyan Angelov <delian66@gmail.com>
Date: Sat, 12 Jun 2021 15:01:52 +0300
Subject: [PATCH] ast: improve Expr.str() for `sizeof(Type)` and
 `__offsetof(StructName, fieldname)`, for more informative asserts/dumps

---
 vlib/v/ast/str.v                                 |  9 ++++++---
 vlib/v/ast/table.v                               | 10 ++++++++++
 vlib/v/tests/failing_tests_test.v                | 13 ++++++++++++-
 .../tests/testdata/sizeof_used_in_assert_test.v  | 16 ++++++++++++++++
 4 files changed, 44 insertions(+), 4 deletions(-)
 create mode 100644 vlib/v/tests/testdata/sizeof_used_in_assert_test.v

diff --git a/vlib/v/ast/str.v b/vlib/v/ast/str.v
index 537fb8d7ee..7ecebf5654 100644
--- a/vlib/v/ast/str.v
+++ b/vlib/v/ast/str.v
@@ -248,7 +248,7 @@ pub fn (x Expr) str() string {
 			}
 		}
 		AsCast {
-			return '$x.expr.str() as Type($x.typ)'
+			return '$x.expr.str() as ${global_table.type_to_str(x.typ)}'
 		}
 		AtExpr {
 			return '$x.val'
@@ -299,6 +299,9 @@ pub fn (x Expr) str() string {
 		FloatLiteral, IntegerLiteral {
 			return x.val
 		}
+		GoExpr {
+			return 'go $x.call_expr'
+		}
 		Ident {
 			return x.name
 		}
@@ -354,12 +357,12 @@ pub fn (x Expr) str() string {
 		}
 		SizeOf {
 			if x.is_type {
-				return 'sizeof(Type($x.typ))'
+				return 'sizeof(${global_table.type_to_str(x.typ)})'
 			}
 			return 'sizeof($x.expr)'
 		}
 		OffsetOf {
-			return '__offsetof($x.struct_type, $x.field)'
+			return '__offsetof(${global_table.type_to_str(x.struct_type)}, $x.field)'
 		}
 		StringInterLiteral {
 			mut res := strings.new_builder(50)
diff --git a/vlib/v/ast/table.v b/vlib/v/ast/table.v
index 3220949ce0..53fe9660dc 100644
--- a/vlib/v/ast/table.v
+++ b/vlib/v/ast/table.v
@@ -159,9 +159,19 @@ pub fn new_table() &Table {
 	}
 	t.register_builtin_type_symbols()
 	t.is_fmt = true
+	set_global_table(t)
 	return t
 }
 
+const global_table = &Table(0)
+
+pub fn set_global_table(t &Table) {
+	unsafe {
+		mut pg := &ast.global_table
+		*pg = t
+	}
+}
+
 // used to compare fn's & for naming anon fn's
 pub fn (t &Table) fn_type_signature(f &Fn) string {
 	mut sig := ''
diff --git a/vlib/v/tests/failing_tests_test.v b/vlib/v/tests/failing_tests_test.v
index de764e1f2c..7615f9d881 100644
--- a/vlib/v/tests/failing_tests_test.v
+++ b/vlib/v/tests/failing_tests_test.v
@@ -15,7 +15,18 @@ fn testsuite_begin() {
 fn test_returning_options() {
 	res := vexecute('vlib/v/tests/testdata/tests_returning_options_failing_test.v')
 	assert res.exit_code == 1
-	dump(res)
+	// dump(res)
 	assert res.output.contains('tests_returning_options_failing_test.v:13: fn test_example failed propagation with error: failing test with return, err: oh no')
 	assert res.output.contains('tests_returning_options_failing_test.v:19: fn test_example_2 failed propagation with error: oh no')
 }
+
+fn test_sizeof_in_assert() {
+	res := vexecute('vlib/v/tests/testdata/sizeof_used_in_assert_test.v')
+	assert res.exit_code == 1
+	// dump(res)
+	assert res.output.contains('sizeof_used_in_assert_test.v:11: fn test_assert_offsetof')
+	assert res.output.contains('assert __offsetof(main.Abc, y) == 1')
+	//
+	assert res.output.contains('sizeof_used_in_assert_test.v:15: fn test_assert_sizeof')
+	assert res.output.contains('assert sizeof(main.Abc) == sizeof(main.Xyz)')
+}
diff --git a/vlib/v/tests/testdata/sizeof_used_in_assert_test.v b/vlib/v/tests/testdata/sizeof_used_in_assert_test.v
new file mode 100644
index 0000000000..8e70f79199
--- /dev/null
+++ b/vlib/v/tests/testdata/sizeof_used_in_assert_test.v
@@ -0,0 +1,16 @@
+struct Abc {
+	x [20]int
+	y [30]int
+}
+
+struct Xyz {
+	x int = 5
+}
+
+fn test_assert_offsetof() {
+	assert __offsetof(Abc, y) == 1
+}
+
+fn test_assert_sizeof() {
+	assert sizeof(Abc) == sizeof(Xyz)
+}