fix(js_analyze): update noPrecisionLoss to correctly handle large hex literals

Author: JeremyMoeglich

crates/biome_js_analyze/src/lint/correctness/no_precision_loss.rs

@@ -1,6 +1,3 @@
-use std::num::IntErrorKind;
-use std::ops::RangeInclusive;
-
 use biome_analyze::context::RuleContext;
 use biome_analyze::{Ast, Rule, RuleDiagnostic, RuleSource, declare_lint_rule};
 use biome_console::markup;
@@ -120,21 +117,64 @@ fn is_precision_lost_in_base_10(num: &str) -> Option<bool> {
 }
 
 fn is_precision_lost_in_base_other(num: &str, radix: u8) -> bool {
-    let parsed = match i64::from_str_radix(num, radix as u32) {
-        Ok(x) => x,
-        Err(e) => {
-            return matches!(
-                e.kind(),
-                IntErrorKind::PosOverflow | IntErrorKind::NegOverflow
-            );
+    let mut msb: Option<u64> = None;
+    let mut lsb: Option<u64> = None;
+    let mut current_bit_index: u64 = 0;
+
+    // Iterate over digits in reverse order (least significant first)
+    for c in num.chars().rev() {
+        if c == '_' {
+            continue;
         }
-    };
+        let digit = match c.to_digit(radix as u32) {
+            Some(d) => d,
+            None => return false, // Should not happen for valid literals
+        };
+
+        // Check bits of the digit
+        let bits_per_digit = match radix {
+            16 => 4,
+            8 => 3,
+            2 => 1,
+            _ => unreachable!("radix must be 2, 8, or 16"),
+        };
+
+        for i in 0..bits_per_digit {
+            if (digit >> i) & 1 == 1 {
+                let bit_pos = current_bit_index + i;
+                if lsb.is_none() {
+                    lsb = Some(bit_pos);
+                }
+                msb = Some(bit_pos);
+            }
+        }
+        current_bit_index += bits_per_digit;
+    }
 
-    const MAX_SAFE_INTEGER: i64 = 2_i64.pow(53) - 1;
-    const MIN_SAFE_INTEGER: i64 = -MAX_SAFE_INTEGER;
-    const SAFE_RANGE: RangeInclusive<i64> = MIN_SAFE_INTEGER..=MAX_SAFE_INTEGER;
+    if let (Some(msb), Some(lsb)) = (msb, lsb) {
+        // Check for overflow (exponent > 1023)
+        // In IEEE 754 double precision:
+        // - The exponent bias is 1023.
+        // - The maximum valid exponent is 1023 (representing 2^1023).
+        // - 2^1024 overflows to Infinity.
+        // Thus, if the most significant bit is at index 1024 or greater, the number overflows.
+        if msb >= 1024 {
+            return true;
+        }
+
+        // Check for precision loss
+        // In IEEE 754 double precision:
+        // - The significand (mantissa) has 53 bits of precision (52 stored bits + 1 implicit leading bit).
+        // - If the distance between the most significant bit (MSB) and the least significant bit (LSB)
+        //   exceeds 53 bits, the number cannot be exactly represented, as the lower bits would be truncated.
+        // Span = MSB - LSB + 1
+        let span = msb - lsb + 1;
 
-    !SAFE_RANGE.contains(&parsed)
+        span > 53
+    } else {
+        // Value is 0
+        false
+    }
 }
 
 fn remove_leading_zeros(num: &str) -> &str {

crates/biome_js_analyze/tests/specs/correctness/noPrecisionLoss/invalid.js

@@ -33,4 +33,10 @@ var x = 0B10000000000_0000000000000000000000000000_000000000000001
 var x = 0o4_00000000000000_001
 var x = 0O4_0000000000000000_1
 var x = 0x2_0000000000001
-var x = 0X200000_0000000_1
+var x = 0X200000_0000000_1
+// From repro_issue.js
+var x = 0x20000000000001; // 2^53 + 1 (Invalid, precision loss)
+var x = 9007199254740993; // 2^53 + 1 (Invalid, precision loss)
+var x = 0x10000000000000000000000001; // 2^100 + 1 (Invalid, precision loss)
+// 2^1024 (Overflow, Invalid)
+var x = 0x10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000;

crates/biome_js_analyze/tests/specs/correctness/noPrecisionLoss/invalid.js.snap

@@ -1,7 +1,6 @@
 ---
 source: crates/biome_js_analyze/tests/spec_tests.rs
 expression: invalid.js
-snapshot_kind: text
 ---
 # Input
 ```js
@@ -41,6 +40,13 @@ var x = 0o4_00000000000000_001
 var x = 0O4_0000000000000000_1
 var x = 0x2_0000000000001
 var x = 0X200000_0000000_1
+// From repro_issue.js
+var x = 0x20000000000001; // 2^53 + 1 (Invalid, precision loss)
+var x = 9007199254740993; // 2^53 + 1 (Invalid, precision loss)
+var x = 0x10000000000000000000000001; // 2^100 + 1 (Invalid, precision loss)
+// 2^1024 (Overflow, Invalid)
+var x = 0x10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000;
+
 ```
 
 # Diagnostics
@@ -614,6 +620,7 @@ invalid.js:35:9 lint/correctness/noPrecisionLoss ━━━━━━━━━━
   > 35 │ var x = 0x2_0000000000001
        │         ^^^^^^^^^^^^^^^^^
     36 │ var x = 0X200000_0000000_1
+    37 │ // From repro_issue.js
   
   i The value at runtime will be 9007199254740992
   
@@ -629,8 +636,77 @@ invalid.js:36:9 lint/correctness/noPrecisionLoss ━━━━━━━━━━
     35 │ var x = 0x2_0000000000001
   > 36 │ var x = 0X200000_0000000_1
        │         ^^^^^^^^^^^^^^^^^^
+    37 │ // From repro_issue.js
+    38 │ var x = 0x20000000000001; // 2^53 + 1 (Invalid, precision loss)
+  
+  i The value at runtime will be 9007199254740992
+  
+
+```
+
+```
+invalid.js:38:9 lint/correctness/noPrecisionLoss ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  × This number literal will lose precision at runtime.
+  
+    36 │ var x = 0X200000_0000000_1
+    37 │ // From repro_issue.js
+  > 38 │ var x = 0x20000000000001; // 2^53 + 1 (Invalid, precision loss)
+       │         ^^^^^^^^^^^^^^^^
+    39 │ var x = 9007199254740993; // 2^53 + 1 (Invalid, precision loss)
+    40 │ var x = 0x10000000000000000000000001; // 2^100 + 1 (Invalid, precision loss)
   
   i The value at runtime will be 9007199254740992
   
 
 ```
+
+```
+invalid.js:39:9 lint/correctness/noPrecisionLoss ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  × This number literal will lose precision at runtime.
+  
+    37 │ // From repro_issue.js
+    38 │ var x = 0x20000000000001; // 2^53 + 1 (Invalid, precision loss)
+  > 39 │ var x = 9007199254740993; // 2^53 + 1 (Invalid, precision loss)
+       │         ^^^^^^^^^^^^^^^^
+    40 │ var x = 0x10000000000000000000000001; // 2^100 + 1 (Invalid, precision loss)
+    41 │ // 2^1024 (Overflow, Invalid)
+  
+  i The value at runtime will be 9007199254740992
+  
+
+```
+
+```
+invalid.js:40:9 lint/correctness/noPrecisionLoss ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  × This number literal will lose precision at runtime.
+  
+    38 │ var x = 0x20000000000001; // 2^53 + 1 (Invalid, precision loss)
+    39 │ var x = 9007199254740993; // 2^53 + 1 (Invalid, precision loss)
+  > 40 │ var x = 0x10000000000000000000000001; // 2^100 + 1 (Invalid, precision loss)
+       │         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    41 │ // 2^1024 (Overflow, Invalid)
+    42 │ var x = 0x10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000;
+  
+  i The value at runtime will be 1267650600228229400000000000000
+  
+
+```
+
+```
+invalid.js:42:9 lint/correctness/noPrecisionLoss ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  × This number literal will lose precision at runtime.
+  
+    40 │ var x = 0x10000000000000000000000001; // 2^100 + 1 (Invalid, precision loss)
+    41 │ // 2^1024 (Overflow, Invalid)
+  > 42 │ var x = 0x10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000;
+       │         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    43 │ 
+  
+  i The value at runtime will be inf
+  
+
+```

crates/biome_js_analyze/tests/specs/correctness/noPrecisionLoss/valid.js

@@ -76,4 +76,10 @@ var x = 0X1_FFF_FFFF_FFF_FFF
 123_00000000000000000000_00.0_0;
 
 var MAX = 1.7976931348623157e+308;
-var MIN = 5e-324;
+var MIN = 5e-324;
+// From repro_issue.js
+var x = 0x20000000000000; // 2^53 (Valid)
+var x = 9007199254740992; // 2^53 (Valid)
+var x = 0x10000000000000000000000000; // 2^100 (Valid)
+// 2^1023 (Max exponent, Valid)
+var x = 0x8000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000;

crates/biome_js_analyze/tests/specs/correctness/noPrecisionLoss/valid.js.snap

@@ -83,4 +83,11 @@ var x = 0X1_FFF_FFFF_FFF_FFF
 
 var MAX = 1.7976931348623157e+308;
 var MIN = 5e-324;
+// From repro_issue.js
+var x = 0x20000000000000; // 2^53 (Valid)
+var x = 9007199254740992; // 2^53 (Valid)
+var x = 0x10000000000000000000000000; // 2^100 (Valid)
+// 2^1023 (Max exponent, Valid)
+var x = 0x8000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000;
+
 ```