From 900ec70711efd1298d4c77d7cab7438085eabd72 Mon Sep 17 00:00:00 2001
From: Pierre Curto <pierre.curto@gmail.com>
Date: Wed, 24 Jan 2024 17:36:39 +0100
Subject: [PATCH] checker: add cast overflow checks (#20641)

---
 vlib/math/big/array_ops_test.v                |  8 ++---
 vlib/strconv/f32_str.c.v                      |  2 --
 vlib/v/checker/checker.v                      | 28 +++++++++++++++
 .../tests/cast_integer_with_overflow_err.out  | 34 +++++++++++++++++++
 .../tests/cast_integer_with_overflow_err.vv   | 10 ++++++
 5 files changed, 76 insertions(+), 6 deletions(-)
 create mode 100644 vlib/v/checker/tests/cast_integer_with_overflow_err.out
 create mode 100644 vlib/v/checker/tests/cast_integer_with_overflow_err.vv

diff --git a/vlib/math/big/array_ops_test.v b/vlib/math/big/array_ops_test.v
index 813fe31e9..40d0bc5cf 100644
--- a/vlib/math/big/array_ops_test.v
+++ b/vlib/math/big/array_ops_test.v
@@ -198,13 +198,13 @@ fn test_left_and_right_shift() {
 	shift_digits_left(r, 1, mut r)
 	assert r == b
 
-	mut c := [u32(0xffffffff)]
+	mut c := [u32(0xffff_ffff)]
 	shift_digits_left(c, 16, mut c)
-	assert c == [u32(0xfffff0000), 0xffff]
+	assert c == [u32(0xffff_0000), 0xffff]
 	shift_digits_right(c, 8, mut c)
-	assert c == [u32(0xfffffff00), 0xff]
+	assert c == [u32(0xffff_ff00), 0xff]
 	shift_digits_right(c, 16, mut c)
-	assert c == [u32(0x00ffffff)]
+	assert c == [u32(0x00ff_ffff)]
 	shift_digits_right(c, 16, mut c)
 	assert c == [u32(0xff)]
 	shift_digits_right(c, 16, mut c)
diff --git a/vlib/strconv/f32_str.c.v b/vlib/strconv/f32_str.c.v
index 72c69778b..e9dfde378 100644
--- a/vlib/strconv/f32_str.c.v
+++ b/vlib/strconv/f32_str.c.v
@@ -32,8 +32,6 @@ const ten_pow_table_32 = [
 	u32(10000000),
 	u32(100000000),
 	u32(1000000000),
-	u32(10000000000),
-	u32(100000000000),
 ]!
 
 //=============================================================================
diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index ca567a255..f8d641493 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -3,6 +3,7 @@
 module checker
 
 import os
+import strconv
 import v.ast
 import v.vmod
 import v.token
@@ -3292,6 +3293,33 @@ fn (mut c Checker) cast_expr(mut node ast.CastExpr) ast.Type {
 			}
 			c.error(error_msg, node.pos)
 		}
+	} else if to_type.is_int() && mut node.expr is ast.IntegerLiteral {
+		tt := c.table.type_to_str(to_type)
+		tsize, _ := c.table.type_size(to_type.idx())
+		bit_size := tsize * 8
+		value_string := match node.expr.val[0] {
+			`-`, `+` {
+				node.expr.val[1..]
+			}
+			else {
+				node.expr.val
+			}
+		}
+		_, e := strconv.common_parse_uint2(value_string, 0, bit_size)
+		match e {
+			0 {}
+			-3 {
+				c.error('value `${node.expr.val}` overflows `${tt}`', node.pos)
+			}
+			else {
+				c.error('cannot cast value `${node.expr.val}` to `${tt}`', node.pos)
+			}
+		}
+	} else if to_type.is_float() && mut node.expr is ast.FloatLiteral {
+		tt := c.table.type_to_str(to_type)
+		strconv.atof64(node.expr.val) or {
+			c.error('cannot cast value `${node.expr.val}` to `${tt}`', node.pos)
+		}
 	}
 	if from_sym.language == .v && !from_type.is_ptr()
 		&& final_from_sym.kind in [.sum_type, .interface_]
diff --git a/vlib/v/checker/tests/cast_integer_with_overflow_err.out b/vlib/v/checker/tests/cast_integer_with_overflow_err.out
new file mode 100644
index 000000000..482a31124
--- /dev/null
+++ b/vlib/v/checker/tests/cast_integer_with_overflow_err.out
@@ -0,0 +1,34 @@
+vlib/v/checker/tests/cast_integer_with_overflow_err.vv:2:7: error: value `300` overflows `u8`
+    1 | fn main() {
+    2 |     a := u8(300)
+      |          ~~~~~~~
+    3 |     _ = a
+    4 |     b := u16(300_000)
+vlib/v/checker/tests/cast_integer_with_overflow_err.vv:4:7: error: value `300000` overflows `u16`
+    2 |     a := u8(300)
+    3 |     _ = a
+    4 |     b := u16(300_000)
+      |          ~~~~~~~~~~~~
+    5 |     _ = b
+    6 |     c := u32(300_000_000_000)
+vlib/v/checker/tests/cast_integer_with_overflow_err.vv:6:7: error: value `300000000000` overflows `u32`
+    4 |     b := u16(300_000)
+    5 |     _ = b
+    6 |     c := u32(300_000_000_000)
+      |          ~~~~~~~~~~~~~~~~~~~~
+    7 |     _ = c
+    8 |     d := u64(300_000_000_000_000_000_000)
+vlib/v/checker/tests/cast_integer_with_overflow_err.vv:8:17: error: integer literal 300000000000000000000 overflows int
+    6 |     c := u32(300_000_000_000)
+    7 |     _ = c
+    8 |     d := u64(300_000_000_000_000_000_000)
+      |                    ~~~~~~~~~~~~~~~~~~~~~
+    9 |     _ = d
+   10 | }
+vlib/v/checker/tests/cast_integer_with_overflow_err.vv:8:7: error: value `300000000000000000000` overflows `u64`
+    6 |     c := u32(300_000_000_000)
+    7 |     _ = c
+    8 |     d := u64(300_000_000_000_000_000_000)
+      |          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+    9 |     _ = d
+   10 | }
diff --git a/vlib/v/checker/tests/cast_integer_with_overflow_err.vv b/vlib/v/checker/tests/cast_integer_with_overflow_err.vv
new file mode 100644
index 000000000..cc56ea5a8
--- /dev/null
+++ b/vlib/v/checker/tests/cast_integer_with_overflow_err.vv
@@ -0,0 +1,10 @@
+fn main() {
+	a := u8(300)
+	_ = a
+	b := u16(300_000)
+	_ = b
+	c := u32(300_000_000_000)
+	_ = c
+	d := u64(300_000_000_000_000_000_000)
+	_ = d
+}
-- 
2.39.5