diff --git a/Cargo.lock b/Cargo.lock
index 2b84b01277b3..9f5606dd4f42 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1923,7 +1923,7 @@ dependencies = [
 [[package]]
 name = "ethers"
 version = "1.0.2"
-source = "git+https://github.com/gakonst/ethers-rs#806af08f99cac0c7e13f13cd527fc87310dae7c4"
+source = "git+https://github.com/gakonst/ethers-rs#1b08a94a858186f825b77517f14bc865cd63a597"
 dependencies = [
  "ethers-addressbook",
  "ethers-contract",
@@ -1938,7 +1938,7 @@ dependencies = [
 [[package]]
 name = "ethers-addressbook"
 version = "1.0.2"
-source = "git+https://github.com/gakonst/ethers-rs#806af08f99cac0c7e13f13cd527fc87310dae7c4"
+source = "git+https://github.com/gakonst/ethers-rs#1b08a94a858186f825b77517f14bc865cd63a597"
 dependencies = [
  "ethers-core",
  "once_cell",
@@ -1949,7 +1949,7 @@ dependencies = [
 [[package]]
 name = "ethers-contract"
 version = "1.0.2"
-source = "git+https://github.com/gakonst/ethers-rs#806af08f99cac0c7e13f13cd527fc87310dae7c4"
+source = "git+https://github.com/gakonst/ethers-rs#1b08a94a858186f825b77517f14bc865cd63a597"
 dependencies = [
  "ethers-contract-abigen",
  "ethers-contract-derive",
@@ -1967,7 +1967,7 @@ dependencies = [
 [[package]]
 name = "ethers-contract-abigen"
 version = "1.0.2"
-source = "git+https://github.com/gakonst/ethers-rs#806af08f99cac0c7e13f13cd527fc87310dae7c4"
+source = "git+https://github.com/gakonst/ethers-rs#1b08a94a858186f825b77517f14bc865cd63a597"
 dependencies = [
  "Inflector",
  "cfg-if 1.0.0",
@@ -1994,7 +1994,7 @@ dependencies = [
 [[package]]
 name = "ethers-contract-derive"
 version = "1.0.2"
-source = "git+https://github.com/gakonst/ethers-rs#806af08f99cac0c7e13f13cd527fc87310dae7c4"
+source = "git+https://github.com/gakonst/ethers-rs#1b08a94a858186f825b77517f14bc865cd63a597"
 dependencies = [
  "ethers-contract-abigen",
  "ethers-core",
@@ -2008,7 +2008,7 @@ dependencies = [
 [[package]]
 name = "ethers-core"
 version = "1.0.2"
-source = "git+https://github.com/gakonst/ethers-rs#806af08f99cac0c7e13f13cd527fc87310dae7c4"
+source = "git+https://github.com/gakonst/ethers-rs#1b08a94a858186f825b77517f14bc865cd63a597"
 dependencies = [
  "arrayvec 0.7.2",
  "bytes",
@@ -2041,7 +2041,7 @@ dependencies = [
 [[package]]
 name = "ethers-etherscan"
 version = "1.0.2"
-source = "git+https://github.com/gakonst/ethers-rs#806af08f99cac0c7e13f13cd527fc87310dae7c4"
+source = "git+https://github.com/gakonst/ethers-rs#1b08a94a858186f825b77517f14bc865cd63a597"
 dependencies = [
  "ethers-core",
  "ethers-solc",
@@ -2058,7 +2058,7 @@ dependencies = [
 [[package]]
 name = "ethers-middleware"
 version = "1.0.2"
-source = "git+https://github.com/gakonst/ethers-rs#806af08f99cac0c7e13f13cd527fc87310dae7c4"
+source = "git+https://github.com/gakonst/ethers-rs#1b08a94a858186f825b77517f14bc865cd63a597"
 dependencies = [
  "async-trait",
  "auto_impl 0.5.0",
@@ -2083,7 +2083,7 @@ dependencies = [
 [[package]]
 name = "ethers-providers"
 version = "1.0.2"
-source = "git+https://github.com/gakonst/ethers-rs#806af08f99cac0c7e13f13cd527fc87310dae7c4"
+source = "git+https://github.com/gakonst/ethers-rs#1b08a94a858186f825b77517f14bc865cd63a597"
 dependencies = [
  "async-trait",
  "auto_impl 1.0.1",
@@ -2122,7 +2122,7 @@ dependencies = [
 [[package]]
 name = "ethers-signers"
 version = "1.0.2"
-source = "git+https://github.com/gakonst/ethers-rs#806af08f99cac0c7e13f13cd527fc87310dae7c4"
+source = "git+https://github.com/gakonst/ethers-rs#1b08a94a858186f825b77517f14bc865cd63a597"
 dependencies = [
  "async-trait",
  "coins-bip32",
@@ -2149,7 +2149,7 @@ dependencies = [
 [[package]]
 name = "ethers-solc"
 version = "1.0.2"
-source = "git+https://github.com/gakonst/ethers-rs#806af08f99cac0c7e13f13cd527fc87310dae7c4"
+source = "git+https://github.com/gakonst/ethers-rs#1b08a94a858186f825b77517f14bc865cd63a597"
 dependencies = [
  "cfg-if 1.0.0",
  "dunce",
@@ -2677,9 +2677,9 @@ dependencies = [
 
 [[package]]
 name = "fs_extra"
-version = "1.2.0"
+version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2022715d62ab30faffd124d40b76f4134a550a87792276512b18d63272333394"
+checksum = "42703706b716c37f96a77aea830392ad231f44c9e9a67872fa5548707e11b11c"
 
 [[package]]
 name = "fsevent-sys"
@@ -4978,9 +4978,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.50"
+version = "1.0.51"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6ef7d57beacfaf2d8aee5937dab7b7f28de3cb8b1828479bb5de2a7106f2bae2"
+checksum = "5d727cae5b39d21da60fa540906919ad737832fe0b1c165da3a34d6548c849d6"
 dependencies = [
  "unicode-ident",
 ]
@@ -6106,9 +6106,9 @@ dependencies = [
 
 [[package]]
 name = "solang-parser"
-version = "0.2.1"
+version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6e9653f278d9531b60f042c29732bb835d519943f4167b1e5684c7e820dd9fec"
+checksum = "58feb14d4002859db0b744b0915840bae403b8a5675efded3e8adddb6beb85b2"
 dependencies = [
  "itertools",
  "lalrpop",
diff --git a/Cargo.toml b/Cargo.toml
index 9056d46daca6..03726b0854ab 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -70,4 +70,4 @@ codegen-units = 1
 # ethers-solc = { path = "../ethers-rs/ethers-solc" }
 
 # [patch.crates-io]
-# revm = { path = "../revm/crates/revm" }
+# revm = { path = "../revm/crates/revm" }
\ No newline at end of file
diff --git a/anvil/tests/it/ganache.rs b/anvil/tests/it/ganache.rs
index ec682825ef5a..fae4ba3469b9 100644
--- a/anvil/tests/it/ganache.rs
+++ b/anvil/tests/it/ganache.rs
@@ -3,7 +3,7 @@
 use crate::init_tracing;
 use ethers::{
     abi::Address,
-    contract::{Contract, ContractFactory},
+    contract::{Contract, ContractFactory, ContractInstance},
     core::k256::SecretKey,
     prelude::{abigen, Middleware, Signer, SignerMiddleware, TransactionRequest, Ws},
     providers::{Http, Provider},
@@ -159,7 +159,7 @@ contract Contract {
         Provider::<Http>::try_from("http://127.0.0.1:8545").unwrap(),
         ganache_wallet2(),
     );
-    let contract = Contract::new(contract.address(), abi.unwrap(), provider);
+    let contract = ContractInstance::new(contract.address(), abi.unwrap(), provider);
     let resp = contract.method::<_, U256>("getSecret", ()).unwrap().legacy().call().await;
     resp.unwrap_err();
 
diff --git a/anvil/tests/it/revert.rs b/anvil/tests/it/revert.rs
index 57ac91384803..f334392087cb 100644
--- a/anvil/tests/it/revert.rs
+++ b/anvil/tests/it/revert.rs
@@ -1,6 +1,6 @@
 use anvil::{spawn, NodeConfig};
 use ethers::{
-    contract::{Contract, ContractFactory},
+    contract::{ContractFactory, ContractInstance},
     middleware::SignerMiddleware,
     types::U256,
     utils::WEI_IN_ETHER,
@@ -82,7 +82,7 @@ contract Contract {
     let factory = ContractFactory::new(abi.clone().unwrap(), bytecode.unwrap(), client);
     let contract = factory.deploy(()).unwrap().send().await.unwrap();
 
-    let contract = Contract::new(
+    let contract = ContractInstance::new(
         contract.address(),
         abi.unwrap(),
         SignerMiddleware::new(handle.http_provider(), wallets[1].clone()),
@@ -139,7 +139,7 @@ async fn test_solc_revert_example() {
     let factory = ContractFactory::new(abi.clone().unwrap(), bytecode.unwrap(), client);
     let contract = factory.deploy(()).unwrap().send().await.unwrap();
 
-    let contract = Contract::new(
+    let contract = ContractInstance::new(
         contract.address(),
         abi.unwrap(),
         SignerMiddleware::new(handle.http_provider(), wallets[1].clone()),
@@ -193,7 +193,7 @@ contract Contract {
     let factory = ContractFactory::new(abi.clone().unwrap(), bytecode.unwrap(), client);
     let contract = factory.deploy(()).unwrap().send().await.unwrap();
 
-    let contract = Contract::new(
+    let contract = ContractInstance::new(
         contract.address(),
         abi.unwrap(),
         SignerMiddleware::new(handle.http_provider(), wallets[1].clone()),
diff --git a/anvil/tests/it/traces.rs b/anvil/tests/it/traces.rs
index 22a5b8ecf6f1..53c86b926c01 100644
--- a/anvil/tests/it/traces.rs
+++ b/anvil/tests/it/traces.rs
@@ -1,7 +1,7 @@
 use crate::fork::fork_config;
 use anvil::{spawn, NodeConfig};
 use ethers::{
-    contract::Contract,
+    contract::ContractInstance,
     prelude::{
         Action, ContractFactory, GethTrace, GethTraceFrame, Middleware, Signer, SignerMiddleware,
         TransactionRequest,
@@ -80,7 +80,7 @@ contract Contract {
     let factory = ContractFactory::new(abi.clone().unwrap(), bytecode.unwrap(), client);
     let contract = factory.deploy(()).unwrap().send().await.unwrap();
 
-    let contract = Contract::new(
+    let contract = ContractInstance::new(
         contract.address(),
         abi.unwrap(),
         SignerMiddleware::new(handle.http_provider(), wallets[1].clone()),
@@ -127,7 +127,7 @@ contract Contract {
     let factory = ContractFactory::new(abi.clone().unwrap(), bytecode.unwrap(), client);
     let contract = factory.deploy(()).unwrap().send().await.unwrap();
 
-    let contract = Contract::new(
+    let contract = ContractInstance::new(
         contract.address(),
         abi.unwrap(),
         SignerMiddleware::new(handle.http_provider(), wallets[1].clone()),
@@ -144,7 +144,7 @@ contract Contract {
             GethTraceFrame::Default(traces) => {
                 assert!(!traces.failed);
             }
-            GethTraceFrame::CallTracer(_) => {
+            _ => {
                 unreachable!()
             }
         },
diff --git a/chisel/Cargo.toml b/chisel/Cargo.toml
index b5a209334ebc..c949ca385de6 100644
--- a/chisel/Cargo.toml
+++ b/chisel/Cargo.toml
@@ -40,7 +40,7 @@ reqwest = { version = "0.11", default-features = false, features = ["rustls"] }
 # misc
 clap = { version = "4.0", features = ["derive", "env", "wrap_help"] }
 rustyline = "10.0.0"
-solang-parser = "=0.2.1"
+solang-parser = "=0.2.2"
 yansi = "0.5.1"
 strum = { version = "0.24.1", features = ["derive"] }
 serde = "1.0.145"
diff --git a/chisel/src/executor.rs b/chisel/src/executor.rs
index d92d098dae0d..770be8b528be 100644
--- a/chisel/src/executor.rs
+++ b/chisel/src/executor.rs
@@ -597,7 +597,7 @@ impl Type {
             pt::Type::Uint(size) => Self::Builtin(ParamType::Uint(*size as usize)),
             pt::Type::Bytes(size) => Self::Builtin(ParamType::FixedBytes(*size as usize)),
             pt::Type::DynamicBytes => Self::Builtin(ParamType::Bytes),
-            pt::Type::Mapping(_, _, right) => Self::from_expression(right)?,
+            pt::Type::Mapping { value, .. } => Self::from_expression(value)?,
             pt::Type::Function { params, returns, .. } => {
                 let params = map_parameters(params);
                 let returns = returns
diff --git a/chisel/src/session_source.rs b/chisel/src/session_source.rs
index 58bf9e6a4aa1..963f706d4068 100644
--- a/chisel/src/session_source.rs
+++ b/chisel/src/session_source.rs
@@ -245,8 +245,8 @@ impl SessionSource {
     /// source.
     pub fn compiler_input(&self) -> CompilerInput {
         let mut sources = Sources::new();
-        sources.insert(PathBuf::from("forge-std/Vm.sol"), Source { content: VM_SOURCE.to_owned() });
-        sources.insert(self.file_name.clone(), Source { content: self.to_repl_source() });
+        sources.insert(PathBuf::from("forge-std/Vm.sol"), Source::new(VM_SOURCE.to_owned()));
+        sources.insert(self.file_name.clone(), Source::new(self.to_repl_source()));
         CompilerInput::with_sources(sources).pop().unwrap()
     }
 
diff --git a/cli/Cargo.toml b/cli/Cargo.toml
index c2dfde2fcfce..77e34802bc01 100644
--- a/cli/Cargo.toml
+++ b/cli/Cargo.toml
@@ -23,7 +23,7 @@ ui = { path = "../ui" }
 
 # eth
 ethers = { git = "https://github.com/gakonst/ethers-rs", default-features = false, features = ["rustls"] }
-solang-parser = "=0.2.1"
+solang-parser = "=0.2.2"
 
 # cli
 clap = { version = "4.0", features = ["derive", "env", "unicode", "wrap_help"] }
diff --git a/cli/src/cmd/forge/script/build.rs b/cli/src/cmd/forge/script/build.rs
index 881292e378d6..f844508a0711 100644
--- a/cli/src/cmd/forge/script/build.rs
+++ b/cli/src/cmd/forge/script/build.rs
@@ -285,7 +285,7 @@ pub fn filter_sources_and_artifacts(
             }
 
             if !is_standalone {
-                target_tree.get(&resolved).map(|source| (id, source.content.clone()))
+                target_tree.get(&resolved).map(|source| (id, source.content.as_str().to_string()))
             } else {
                 Some((
                     id,
diff --git a/cli/src/cmd/forge/verify/etherscan/flatten.rs b/cli/src/cmd/forge/verify/etherscan/flatten.rs
index c962fa4041fd..0fafc99b1673 100644
--- a/cli/src/cmd/forge/verify/etherscan/flatten.rs
+++ b/cli/src/cmd/forge/verify/etherscan/flatten.rs
@@ -74,7 +74,7 @@ impl EtherscanFlattenedSource {
 
         let input = CompilerInput {
             language: "Solidity".to_string(),
-            sources: BTreeMap::from([("contract.sol".into(), Source { content: content.into() })]),
+            sources: BTreeMap::from([("contract.sol".into(), Source::new(content))]),
             settings: Default::default(),
         };
 
diff --git a/config/src/lib.rs b/config/src/lib.rs
index 08656a567b77..d657475b2666 100644
--- a/config/src/lib.rs
+++ b/config/src/lib.rs
@@ -3846,7 +3846,8 @@ mod tests {
                         ModelCheckerTarget::Assert,
                         ModelCheckerTarget::OutOfBounds
                     ]),
-                    timeout: Some(10000)
+                    timeout: Some(10000),
+                    invariants: None,
                 })
             );
 
@@ -3902,7 +3903,8 @@ mod tests {
                         ModelCheckerTarget::Assert,
                         ModelCheckerTarget::OutOfBounds
                     ]),
-                    timeout: Some(10000)
+                    timeout: Some(10000),
+                    invariants: None,
                 })
             );
 
diff --git a/doc/Cargo.toml b/doc/Cargo.toml
index b446fe342ad9..ab948bb34306 100644
--- a/doc/Cargo.toml
+++ b/doc/Cargo.toml
@@ -37,7 +37,7 @@ tokio = { version = "1", features = ["macros", "rt-multi-thread"] }
 futures-util = "0.3.4"
 
 # misc
-solang-parser = "=0.2.1"
+solang-parser = "=0.2.2"
 eyre = "0.6"
 thiserror = "1.0.30"
 rayon = "1.5.1"
diff --git a/doc/src/writer/as_string.rs b/doc/src/writer/as_string.rs
index 5c217f436399..c8e94a7becf9 100644
--- a/doc/src/writer/as_string.rs
+++ b/doc/src/writer/as_string.rs
@@ -25,8 +25,18 @@ impl AsString for Expression {
                 Type::DynamicBytes => "bytes".to_owned(),
                 Type::Int(n) => format!("int{n}"),
                 Type::Uint(n) => format!("uint{n}"),
-                Type::Mapping(_, from, to) => {
-                    format!("mapping({} => {})", from.as_string(), to.as_string())
+                Type::Mapping { key, key_name, value, value_name, .. } => {
+                    let mut key = key.as_string();
+                    if let Some(name) = key_name {
+                        key.push(' ');
+                        key.push_str(&name.to_string());
+                    }
+                    let mut value = value.as_string();
+                    if let Some(name) = value_name {
+                        value.push(' ');
+                        value.push_str(&name.to_string());
+                    }
+                    format!("mapping({key} => {value})")
                 }
                 Type::Function { params, attributes, returns } => {
                     let params = params.as_string();
diff --git a/fmt/Cargo.toml b/fmt/Cargo.toml
index a5bb38723dd0..82737e352261 100644
--- a/fmt/Cargo.toml
+++ b/fmt/Cargo.toml
@@ -16,7 +16,7 @@ foundry-config = { path = "../config" }
 ethers-core = { git = "https://github.com/gakonst/ethers-rs", default-features = false }
 
 # parser
-solang-parser = "=0.2.1"
+solang-parser = "=0.2.2"
 
 # misc
 semver = "1.0.4"
diff --git a/fmt/src/chunk.rs b/fmt/src/chunk.rs
index 05c20d0ccaf2..badce88db567 100644
--- a/fmt/src/chunk.rs
+++ b/fmt/src/chunk.rs
@@ -27,6 +27,7 @@ impl From<&str> for Chunk {
 pub struct SurroundingChunk {
     pub before: Option<usize>,
     pub next: Option<usize>,
+    pub spaced: Option<bool>,
     pub content: String,
 }
 
@@ -36,14 +37,24 @@ impl SurroundingChunk {
         before: Option<usize>,
         next: Option<usize>,
     ) -> Self {
-        SurroundingChunk { before, next, content: format!("{content}") }
+        SurroundingChunk { before, next, content: format!("{content}"), spaced: None }
+    }
+
+    pub fn spaced(mut self) -> Self {
+        self.spaced = Some(true);
+        self
+    }
+
+    pub fn non_spaced(mut self) -> Self {
+        self.spaced = Some(false);
+        self
     }
 
     pub fn loc_before(&self) -> usize {
         self.before.unwrap_or_default()
     }
 
-    pub fn loc_next(&self) -> usize {
-        self.next.unwrap_or_default()
+    pub fn loc_next(&self) -> Option<usize> {
+        self.next
     }
 }
diff --git a/fmt/src/formatter.rs b/fmt/src/formatter.rs
index 5c6f8718a7ae..6c3e9a8db767 100644
--- a/fmt/src/formatter.rs
+++ b/fmt/src/formatter.rs
@@ -887,11 +887,15 @@ impl<'a, W: Write> Formatter<'a, W> {
         last: SurroundingChunk,
         mut fun: impl FnMut(&mut Self, bool) -> Result<()>,
     ) -> Result<()> {
-        write_chunk!(self, first.loc_before(), first.loc_next(), "{}", first.content)?;
+        let first_chunk =
+            self.chunk_at(first.loc_before(), first.loc_next(), first.spaced, first.content);
+        self.write_chunk(&first_chunk)?;
 
         let multiline = !self.try_on_single_line(|fmt| {
             fun(fmt, false)?;
-            write_chunk!(fmt, last.loc_before(), last.loc_next(), "{}", last.content)?;
+            let last_chunk =
+                fmt.chunk_at(last.loc_before(), last.loc_next(), last.spaced, &last.content);
+            fmt.write_chunk(&last_chunk)?;
             Ok(())
         })?;
 
@@ -904,7 +908,9 @@ impl<'a, W: Write> Formatter<'a, W> {
             if !last.content.trim_start().is_empty() {
                 self.write_whitespace_separator(true)?;
             }
-            write_chunk!(self, last.loc_before(), last.loc_next(), "{}", last.content)?;
+            let last_chunk =
+                self.chunk_at(last.loc_before(), last.loc_next(), last.spaced, &last.content);
+            self.write_chunk(&last_chunk)?;
         }
 
         Ok(())
@@ -1931,16 +1937,48 @@ impl<'a, W: Write> Visitor for Formatter<'a, W> {
                         _ => write_chunk!(self, loc.start(), "{int}{n}")?,
                     }
                 }
-                Type::Mapping(loc, from, to) => {
-                    write_chunk!(self, loc.start(), "mapping(")?;
+                Type::Mapping { loc, key, key_name, value, value_name } => {
                     let arrow_loc = self.find_next_str_in_src(loc.start(), "=>");
-                    let key_chunk = self.visit_to_chunk(from.loc().start(), arrow_loc, from)?;
-                    self.write_chunk(&key_chunk)?;
-                    write!(self.buf(), " => ")?;
-                    let close_paren_loc = self.find_next_in_src(to.loc().end(), ')');
-                    let value_chunk = self.visit_to_chunk(to.loc().start(), close_paren_loc, to)?;
-                    self.write_chunk(&value_chunk)?;
-                    write!(self.buf(), ")")?;
+                    let close_paren_loc =
+                        self.find_next_in_src(value.loc().end(), ')').unwrap_or(loc.end());
+                    let first = SurroundingChunk::new(
+                        "mapping(",
+                        Some(loc.start()),
+                        Some(key.loc().start()),
+                    );
+                    let last = SurroundingChunk::new(")", Some(close_paren_loc), Some(loc.end()))
+                        .non_spaced();
+                    self.surrounded(first, last, |fmt, multiline| {
+                        fmt.grouped(|fmt| {
+                            key.visit(fmt)?;
+
+                            if let Some(name) = key_name {
+                                let end_loc = arrow_loc.unwrap_or(value.loc().start());
+                                write_chunk!(fmt, name.loc.start(), end_loc, " {}", name)?;
+                            } else if let Some(arrow_loc) = arrow_loc {
+                                fmt.write_postfix_comments_before(arrow_loc)?;
+                            }
+
+                            let mut write_arrow_and_value = |fmt: &mut Self| {
+                                write!(fmt.buf(), "=> ")?;
+                                value.visit(fmt)?;
+                                if let Some(name) = value_name {
+                                    write_chunk!(fmt, name.loc.start(), " {}", name)?;
+                                }
+                                Ok(())
+                            };
+
+                            let rest_str = fmt.simulate_to_string(&mut write_arrow_and_value)?;
+                            let multiline = multiline && !fmt.will_it_fit(rest_str);
+                            fmt.write_whitespace_separator(multiline)?;
+
+                            write_arrow_and_value(fmt)?;
+
+                            fmt.write_postfix_comments_before(close_paren_loc)?;
+                            fmt.write_prefix_comments_before(close_paren_loc)
+                        })?;
+                        Ok(())
+                    })?;
                 }
                 Type::Function { .. } => self.visit_source(*loc)?,
             },
@@ -3626,4 +3664,5 @@ mod tests {
     test_directory! { TrailingComma }
     test_directory! { PragmaDirective }
     test_directory! { Annotation }
+    test_directory! { MappingType }
 }
diff --git a/fmt/src/solang_ext/ast_eq.rs b/fmt/src/solang_ext/ast_eq.rs
index 6a17aab169ca..d94fc7abb5cc 100644
--- a/fmt/src/solang_ext/ast_eq.rs
+++ b/fmt/src/solang_ext/ast_eq.rs
@@ -483,8 +483,8 @@ derive_ast_eq! { enum Type {
     Int(int),
     Uint(int),
     Bytes(int),
-    Mapping(loc, expr1, expr2),
     _
+    Mapping{ loc, key, key_name, value, value_name },
     Function { params, attributes, returns },
 }}
 derive_ast_eq! { enum Expression {
diff --git a/fmt/testdata/MappingType/fmt.sol b/fmt/testdata/MappingType/fmt.sol
new file mode 100644
index 000000000000..7f6297cff945
--- /dev/null
+++ b/fmt/testdata/MappingType/fmt.sol
@@ -0,0 +1,35 @@
+// config: line_length = 40
+contract X {
+    type Y is bytes32;
+}
+
+type SomeVeryLongTypeName is uint256;
+
+contract Mapping {
+    mapping(uint256 => X.Y) mapping1;
+    mapping(
+        uint256 key => uint256 value
+    ) mapping2;
+    mapping(
+        uint256 veryLongKeyName
+            => uint256 veryLongValueName
+    ) mapping3;
+    mapping(
+        string anotherVeryLongKeyName
+            => uint256 anotherVeryLongValueName
+    ) mapping4;
+    mapping(
+        SomeVeryLongTypeName anotherVeryLongKeyName
+            => uint256 anotherVeryLongValueName
+    ) mapping5;
+
+    mapping(
+        // comment1
+        uint256 key => uint256 value
+        // comment2
+    ) mapping6;
+    mapping( /* comment3 */
+        uint256 /* comment4 */ key /* comment5 */
+            => /* comment6 */ uint256 /* comment7 */ value /* comment8 */ /* comment9 */
+    ) /* comment10 */ mapping7;
+}
diff --git a/fmt/testdata/MappingType/original.sol b/fmt/testdata/MappingType/original.sol
new file mode 100644
index 000000000000..58ebb134d668
--- /dev/null
+++ b/fmt/testdata/MappingType/original.sol
@@ -0,0 +1,23 @@
+contract X {
+    type Y is bytes32;
+}
+
+type SomeVeryLongTypeName is uint256;
+
+contract Mapping {
+    mapping(uint256 => X.Y) mapping1;
+    mapping(uint256 key => uint256 value) mapping2;
+    mapping(uint256 veryLongKeyName => uint256 veryLongValueName) mapping3;
+    mapping(string anotherVeryLongKeyName => uint256 anotherVeryLongValueName) mapping4;
+    mapping(SomeVeryLongTypeName anotherVeryLongKeyName => uint256 anotherVeryLongValueName) mapping5;
+
+    mapping(
+            
+            // comment1
+    uint256 key => uint256 value
+// comment2
+    ) mapping6;
+    mapping( /* comment3 */
+        uint256 /* comment4 */ key /* comment5 */ => /* comment6 */ uint256 /* comment7 */ value /* comment8 */ /* comment9 */
+    )  /* comment10 */ mapping7;
+}
\ No newline at end of file