diff --git a/Cargo.lock b/Cargo.lock
index b9dafd8e..8881d5be 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -39,9 +39,9 @@ name = "async-trait"
 version = "0.1.38"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.23 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.39 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.42 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -79,7 +79,7 @@ dependencies = [
  "lazycell 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "peeking_take_while 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro2 1.0.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.23 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 1.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-hash 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -533,9 +533,9 @@ version = "0.3.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro-hack 0.5.18 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro2 1.0.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.23 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.39 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.42 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1085,9 +1085,9 @@ name = "pg-extern-attr"
 version = "0.2.2"
 dependencies = [
  "pg-extend 0.2.1",
- "proc-macro2 1.0.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.23 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.39 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.42 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1119,9 +1119,9 @@ name = "pin-project-internal"
 version = "0.4.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.23 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.39 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.42 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1196,7 +1196,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.19"
+version = "1.0.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "unicode-xid 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1212,7 +1212,7 @@ name = "quote"
 version = "1.0.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.23 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1364,9 +1364,9 @@ name = "serde_derive"
 version = "1.0.115"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.23 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.39 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.42 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1481,10 +1481,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "syn"
-version = "1.0.39"
+version = "1.0.42"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.23 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-xid 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -1868,7 +1868,7 @@ dependencies = [
 "checksum ppv-lite86 0.2.9 (registry+https://github.com/rust-lang/crates.io-index)" = "c36fa947111f5c62a733b652544dd0016a43ce89619538a8ef92724a6f501a20"
 "checksum proc-macro-hack 0.5.18 (registry+https://github.com/rust-lang/crates.io-index)" = "99c605b9a0adc77b7211c6b1f722dcb613d68d66859a44f3d485a6da332b0598"
 "checksum proc-macro-nested 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "eba180dafb9038b050a4c280019bbedf9f2467b61e5d892dcad585bb57aadc5a"
-"checksum proc-macro2 1.0.19 (registry+https://github.com/rust-lang/crates.io-index)" = "04f5f085b5d71e2188cb8271e5da0161ad52c3f227a661a3c135fdf28e258b12"
+"checksum proc-macro2 1.0.23 (registry+https://github.com/rust-lang/crates.io-index)" = "51ef7cd2518ead700af67bf9d1a658d90b6037d77110fd9c0445429d0ba1c6c9"
 "checksum quick-error 1.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "a1d01941d82fa2ab50be1e79e6714289dd7cde78eba4c074bc5a4374f650dfe0"
 "checksum quote 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)" = "aa563d17ecb180e500da1cfd2b028310ac758de548efdd203e18f283af693f37"
 "checksum rand 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)" = "6a6b1679d49b24bbfe0c803429aa1874472f50d9b363131f0e89fc356b544d03"
@@ -1905,7 +1905,7 @@ dependencies = [
 "checksum strip-ansi-escapes 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "9d63676e2abafa709460982ddc02a3bb586b6d15a49b75c212e06edd3933acee"
 "checksum strsim 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "8ea5119cdb4c55b55d432abb513a0429384878c15dde60cc77b1c99de1a95a6a"
 "checksum subtle 2.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "502d53007c02d7605a05df1c1a73ee436952781653da5d0bf57ad608f66932c1"
-"checksum syn 1.0.39 (registry+https://github.com/rust-lang/crates.io-index)" = "891d8d6567fe7c7f8835a3a98af4208f3846fba258c1bc3c31d6e506239f11f9"
+"checksum syn 1.0.42 (registry+https://github.com/rust-lang/crates.io-index)" = "9c51d92969d209b54a98397e1b91c8ae82d8c87a7bb87df0b29aa2ad81454228"
 "checksum tar 0.4.29 (registry+https://github.com/rust-lang/crates.io-index)" = "c8a4c1d0bee3230179544336c15eefb563cf0302955d962e456542323e8c2e8a"
 "checksum tempfile 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6e24d9338a0a5be79593e2fa15a648add6138caa803e2d5bc782c371732ca9"
 "checksum termcolor 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "bb6bfa289a4d7c5766392812c0a1f4c1ba45afa1ad47803c11e1f407d846d75f"
diff --git a/pg-extern-attr/Cargo.toml b/pg-extern-attr/Cargo.toml
index 7af571bd..ea113e26 100644
--- a/pg-extern-attr/Cargo.toml
+++ b/pg-extern-attr/Cargo.toml
@@ -18,7 +18,7 @@ license = "MIT/Apache-2.0"
 proc-macro = true
 
 [dependencies]
-syn = { version = "1.0.33", features = ["extra-traits", "full", "fold", "parsing"] }
+syn = { version = "1.0.42", features = ["extra-traits", "full", "fold", "parsing"] }
 quote = "1.0.7"
 proc-macro2 = "1.0.17"