diff --git a/Cargo.lock b/Cargo.lock
index e7e8a98f1..58d434700 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -284,7 +284,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "synstructure 0.12.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -732,7 +732,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.15 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -786,7 +786,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.15 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -840,7 +840,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "syn"
-version = "1.0.14"
+version = "1.0.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -855,7 +855,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -958,7 +958,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.15 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1336,7 +1336,7 @@ dependencies = [
 "checksum smallvec 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "5c2fb2ec9bcd216a5b0d0ccf31ab17b5ed1d627960edff65bbe95d3ce221cefc"
 "checksum ssh2 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)" = "26c31781ff1198791fb772771bca3ec962d7243cb8cad79818b2b38be8253e3c"
 "checksum strsim 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "8ea5119cdb4c55b55d432abb513a0429384878c15dde60cc77b1c99de1a95a6a"
-"checksum syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)" = "af6f3550d8dff9ef7dc34d384ac6f107e5d31c8f57d9f28e0081503f547ac8f5"
+"checksum syn 1.0.15 (registry+https://github.com/rust-lang/crates.io-index)" = "7a0294dc449adc58bb6592fff1a23d3e5e6e235afc6a0ffca2657d19e7bbffe5"
 "checksum synstructure 0.12.3 (registry+https://github.com/rust-lang/crates.io-index)" = "67656ea1dc1b41b1451851562ea232ec2e5a80242139f7e679ceccfb5d61f545"
 "checksum syntex 0.42.2 (registry+https://github.com/rust-lang/crates.io-index)" = "0a30b08a6b383a22e5f6edc127d169670d48f905bb00ca79a00ea3e442ebe317"
 "checksum syntex_errors 0.42.0 (registry+https://github.com/rust-lang/crates.io-index)" = "04c48f32867b6114449155b2a82114b86d4b09e1bddb21c47ff104ab9172b646"