Add support for Solidity 0.8.31 (#1479)

Add support for Solidity 0.8.31

- Added new Yul builtin `clz`


https://www.soliditylang.org/blog/2025/12/03/solidity-0.8.31-release-announcement

Author: teofr

.changeset/wise-garlics-peel.md

@@ -0,0 +1,5 @@
+---
+"@nomicfoundation/slang": patch
+---
+
+Add support for Solidity `0.8.31`

crates/solidity-v2/inputs/language/src/definition.rs

@@ -27,7 +27,7 @@ language_v2_macros::compile!(Language(
         "0.8.2", "0.8.3", "0.8.4", "0.8.5", "0.8.6", "0.8.7", "0.8.8", "0.8.9", "0.8.10", "0.8.11",
         "0.8.12", "0.8.13", "0.8.14", "0.8.15", "0.8.16", "0.8.17", "0.8.18", "0.8.19", "0.8.20",
         "0.8.21", "0.8.22", "0.8.23", "0.8.24", "0.8.25", "0.8.26", "0.8.27", "0.8.28", "0.8.29",
-        "0.8.30"
+        "0.8.30", "0.8.31"
     ],
     sections = [
         Section(
@@ -6917,6 +6917,12 @@ language_v2_macros::compile!(Language(
                     name = "mcopy",
                     parameters = ["uint256 t", "uint256 f", "uint256 s"],
                     enabled = From("0.8.24")
+                ),
+                BuiltInFunction(
+                    name = "clz",
+                    parameters = ["uint256 x"],
+                    return_type = "uint256",
+                    enabled = From("0.8.31")
                 )
             ]
         )

crates/solidity-v2/outputs/cargo/common/src/versions/language_versions.generated.rs

@@ -27,7 +27,7 @@ language_macros::compile!(Language(
         "0.8.2", "0.8.3", "0.8.4", "0.8.5", "0.8.6", "0.8.7", "0.8.8", "0.8.9", "0.8.10", "0.8.11",
         "0.8.12", "0.8.13", "0.8.14", "0.8.15", "0.8.16", "0.8.17", "0.8.18", "0.8.19", "0.8.20",
         "0.8.21", "0.8.22", "0.8.23", "0.8.24", "0.8.25", "0.8.26", "0.8.27", "0.8.28", "0.8.29",
-        "0.8.30"
+        "0.8.30", "0.8.31"
     ],
     sections = [
         Section(
@@ -7193,6 +7193,12 @@ language_macros::compile!(Language(
                     name = "mcopy",
                     parameters = ["uint256 t", "uint256 f", "uint256 s"],
                     enabled = From("0.8.24")
+                ),
+                BuiltInFunction(
+                    name = "clz",
+                    parameters = ["uint256 x"],
+                    return_type = "uint256",
+                    enabled = From("0.8.31")
                 )
             ]
         )

crates/solidity/inputs/language/src/definition.rs

@@ -6,8 +6,8 @@ use crate::cst::NodeId;
 use crate::utils::versions::{
     VERSION_0_4_12, VERSION_0_4_17, VERSION_0_4_21, VERSION_0_4_22, VERSION_0_5_0, VERSION_0_5_3,
     VERSION_0_6_0, VERSION_0_6_2, VERSION_0_6_7, VERSION_0_6_8, VERSION_0_7_0, VERSION_0_8_0,
-    VERSION_0_8_11, VERSION_0_8_15, VERSION_0_8_18, VERSION_0_8_2, VERSION_0_8_24, VERSION_0_8_4,
-    VERSION_0_8_7, VERSION_0_8_8,
+    VERSION_0_8_11, VERSION_0_8_15, VERSION_0_8_18, VERSION_0_8_2, VERSION_0_8_24, VERSION_0_8_31,
+    VERSION_0_8_4, VERSION_0_8_7, VERSION_0_8_8,
 };
 
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
@@ -108,6 +108,7 @@ pub enum BuiltIn {
     YulCall,
     YulCallvalue,
     YulChainid,
+    YulClz,
     YulCodecopy,
     YulCodesize,
     YulCoinbase,
@@ -238,6 +239,8 @@ impl<'a> BuiltInsResolver<'a> {
 
     #[allow(clippy::too_many_lines)]
     pub(crate) fn lookup_yul_global(&self, symbol: &str) -> Option<BuiltIn> {
+        // TODO(validation): Yul built-in function names should be considered reserved words.
+        // They're currently parsed as Identifiers to facilitate their manipulation.
         match symbol {
             "add" => Some(BuiltIn::YulAdd),
             "addmod" => Some(BuiltIn::YulAddmod),
@@ -259,6 +262,7 @@ impl<'a> BuiltInsResolver<'a> {
             "call" => Some(BuiltIn::YulCall),
             "callvalue" => Some(BuiltIn::YulCallvalue),
             "chainid" => Some(BuiltIn::YulChainid),
+            "clz" if self.language_version >= VERSION_0_8_31 => Some(BuiltIn::YulClz),
             "codecopy" => Some(BuiltIn::YulCodecopy),
             "codesize" => Some(BuiltIn::YulCodesize),
             "coinbase" => Some(BuiltIn::YulCoinbase),

crates/solidity/outputs/cargo/crate/src/backend/built_ins.rs

@@ -32,6 +32,8 @@ impl Visitor for Pass {
             input_ir::visitor::accept_inheritance_type(inheritance_type, self);
         }
         if let Some(ref storage_layout) = node.storage_layout {
+            // TODO(validation): check that the expression is not binding constant variables up until 0.8.31
+            // https://www.soliditylang.org/blog/2025/12/03/solidity-0.8.31-release-announcement
             input_ir::visitor::accept_expression(storage_layout, self);
         }