diff --git a/tests/compiletest.rs b/tests/compiletest.rs
index c554d5a..2a481ad 100644
--- a/tests/compiletest.rs
+++ b/tests/compiletest.rs
@@ -5,7 +5,14 @@
     compiletest::run_tests(&compiletest::Config {
         mode: compiletest::common::Mode::Ui,
         src_base: std::path::PathBuf::from("tests/ui"),
-        target_rustcflags: Some(String::from("-L tests/deps/target/debug/deps")),
+        target_rustcflags: Some(String::from(
+            "\
+             --edition=2018 \
+             -L tests/deps/target/debug/deps \
+             -Z unstable-options \
+             --extern serde_json \
+             ",
+        )),
         ..Default::default()
     });
 }
diff --git a/tests/ui/missing_colon.rs b/tests/ui/missing_colon.rs
index 98d4f2c..d93b7b9 100644
--- a/tests/ui/missing_colon.rs
+++ b/tests/ui/missing_colon.rs
@@ -1,5 +1,4 @@
-#[macro_use]
-extern crate serde_json;
+use serde_json::json;
 
 fn main() {
     json!({ "a" });
diff --git a/tests/ui/missing_colon.stderr b/tests/ui/missing_colon.stderr
index b854d44..eec0ebd 100644
--- a/tests/ui/missing_colon.stderr
+++ b/tests/ui/missing_colon.stderr
@@ -1,7 +1,7 @@
 error: unexpected end of macro invocation
- --> $DIR/missing_colon.rs:5:5
+ --> $DIR/missing_colon.rs:4:5
   |
-5 |     json!({ "a" });
+4 |     json!({ "a" });
   |     ^^^^^^^^^^^^^^^ missing tokens in macro arguments
   |
   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
diff --git a/tests/ui/missing_value.rs b/tests/ui/missing_value.rs
index d72a49d..0ba14e2 100644
--- a/tests/ui/missing_value.rs
+++ b/tests/ui/missing_value.rs
@@ -1,5 +1,4 @@
-#[macro_use]
-extern crate serde_json;
+use serde_json::json;
 
 fn main() {
     json!({ "a" : });
diff --git a/tests/ui/missing_value.stderr b/tests/ui/missing_value.stderr
index 6d088ed..fc5a46d 100644
--- a/tests/ui/missing_value.stderr
+++ b/tests/ui/missing_value.stderr
@@ -1,7 +1,7 @@
 error: unexpected end of macro invocation
- --> $DIR/missing_value.rs:5:5
+ --> $DIR/missing_value.rs:4:5
   |
-5 |     json!({ "a" : });
+4 |     json!({ "a" : });
   |     ^^^^^^^^^^^^^^^^^ missing tokens in macro arguments
   |
   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
diff --git a/tests/ui/not_found.rs b/tests/ui/not_found.rs
index 08b802f..2df6870 100644
--- a/tests/ui/not_found.rs
+++ b/tests/ui/not_found.rs
@@ -1,5 +1,4 @@
-#[macro_use]
-extern crate serde_json;
+use serde_json::json;
 
 fn main() {
     json!({ "a" : x });
diff --git a/tests/ui/not_found.stderr b/tests/ui/not_found.stderr
index b544b37..6b39db1 100644
--- a/tests/ui/not_found.stderr
+++ b/tests/ui/not_found.stderr
@@ -1,7 +1,7 @@
 error[E0425]: cannot find value `x` in this scope
- --> $DIR/not_found.rs:5:19
+ --> $DIR/not_found.rs:4:19
   |
-5 |     json!({ "a" : x });
+4 |     json!({ "a" : x });
   |                   ^ not found in this scope
 
 error: aborting due to previous error
diff --git a/tests/ui/parse_expr.rs b/tests/ui/parse_expr.rs
index bcc58ae..e7f1805 100644
--- a/tests/ui/parse_expr.rs
+++ b/tests/ui/parse_expr.rs
@@ -1,5 +1,4 @@
-#[macro_use]
-extern crate serde_json;
+use serde_json::json;
 
 fn main() {
     json!({ "a" : ~ });
diff --git a/tests/ui/parse_expr.stderr b/tests/ui/parse_expr.stderr
index 76bbcaa..c182361 100644
--- a/tests/ui/parse_expr.stderr
+++ b/tests/ui/parse_expr.stderr
@@ -1,7 +1,7 @@
 error: unexpected end of macro invocation
- --> $DIR/parse_expr.rs:5:5
+ --> $DIR/parse_expr.rs:4:5
   |
-5 |     json!({ "a" : ~ });
+4 |     json!({ "a" : ~ });
   |     ^^^^^^^^^^^^^^^^^^^ missing tokens in macro arguments
   |
   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
diff --git a/tests/ui/parse_key.rs b/tests/ui/parse_key.rs
index e7f4e27..858bd71 100644
--- a/tests/ui/parse_key.rs
+++ b/tests/ui/parse_key.rs
@@ -1,5 +1,4 @@
-#[macro_use]
-extern crate serde_json;
+use serde_json::json;
 
 fn main() {
     json!({ "".s : true });
diff --git a/tests/ui/parse_key.stderr b/tests/ui/parse_key.stderr
index c1485a0..c91afcd 100644
--- a/tests/ui/parse_key.stderr
+++ b/tests/ui/parse_key.stderr
@@ -1,7 +1,7 @@
 error[E0609]: no field `s` on type `&'static str`
- --> $DIR/parse_key.rs:5:16
+ --> $DIR/parse_key.rs:4:16
   |
-5 |     json!({ "".s : true });
+4 |     json!({ "".s : true });
   |                ^
 
 error: aborting due to previous error
diff --git a/tests/ui/unexpected_after_array_element.rs b/tests/ui/unexpected_after_array_element.rs
index f8f3e91..226c58c 100644
--- a/tests/ui/unexpected_after_array_element.rs
+++ b/tests/ui/unexpected_after_array_element.rs
@@ -1,5 +1,4 @@
-#[macro_use]
-extern crate serde_json;
+use serde_json::json;
 
 fn main() {
     json!([ true => ]);
diff --git a/tests/ui/unexpected_after_array_element.stderr b/tests/ui/unexpected_after_array_element.stderr
index 5b45a0a..835229b 100644
--- a/tests/ui/unexpected_after_array_element.stderr
+++ b/tests/ui/unexpected_after_array_element.stderr
@@ -1,7 +1,7 @@
 error: no rules expected the token `=>`
- --> $DIR/unexpected_after_array_element.rs:5:18
+ --> $DIR/unexpected_after_array_element.rs:4:18
   |
-5 |     json!([ true => ]);
+4 |     json!([ true => ]);
   |                  ^^ no rules expected this token in macro call
 
 error: aborting due to previous error
diff --git a/tests/ui/unexpected_after_map_entry.rs b/tests/ui/unexpected_after_map_entry.rs
index 4018541..0dfb731 100644
--- a/tests/ui/unexpected_after_map_entry.rs
+++ b/tests/ui/unexpected_after_map_entry.rs
@@ -1,5 +1,4 @@
-#[macro_use]
-extern crate serde_json;
+use serde_json::json;
 
 fn main() {
     json!({ "k": true => });
diff --git a/tests/ui/unexpected_after_map_entry.stderr b/tests/ui/unexpected_after_map_entry.stderr
index df58a06..02484c8 100644
--- a/tests/ui/unexpected_after_map_entry.stderr
+++ b/tests/ui/unexpected_after_map_entry.stderr
@@ -1,7 +1,7 @@
 error: no rules expected the token `=>`
- --> $DIR/unexpected_after_map_entry.rs:5:23
+ --> $DIR/unexpected_after_map_entry.rs:4:23
   |
-5 |     json!({ "k": true => });
+4 |     json!({ "k": true => });
   |                       ^^ no rules expected this token in macro call
 
 error: aborting due to previous error
diff --git a/tests/ui/unexpected_colon.rs b/tests/ui/unexpected_colon.rs
index e9a307e..e767ea6 100644
--- a/tests/ui/unexpected_colon.rs
+++ b/tests/ui/unexpected_colon.rs
@@ -1,5 +1,4 @@
-#[macro_use]
-extern crate serde_json;
+use serde_json::json;
 
 fn main() {
     json!({ : true });
diff --git a/tests/ui/unexpected_colon.stderr b/tests/ui/unexpected_colon.stderr
index b379d4e..495bbd9 100644
--- a/tests/ui/unexpected_colon.stderr
+++ b/tests/ui/unexpected_colon.stderr
@@ -1,7 +1,7 @@
 error: no rules expected the token `:`
- --> $DIR/unexpected_colon.rs:5:13
+ --> $DIR/unexpected_colon.rs:4:13
   |
-5 |     json!({ : true });
+4 |     json!({ : true });
   |             ^ no rules expected this token in macro call
 
 error: aborting due to previous error
diff --git a/tests/ui/unexpected_comma.rs b/tests/ui/unexpected_comma.rs
index 66d106d..338874e 100644
--- a/tests/ui/unexpected_comma.rs
+++ b/tests/ui/unexpected_comma.rs
@@ -1,5 +1,4 @@
-#[macro_use]
-extern crate serde_json;
+use serde_json::json;
 
 fn main() {
     json!({ "a" , "b": true });
diff --git a/tests/ui/unexpected_comma.stderr b/tests/ui/unexpected_comma.stderr
index 274cb19..c6d2b66 100644
--- a/tests/ui/unexpected_comma.stderr
+++ b/tests/ui/unexpected_comma.stderr
@@ -1,7 +1,7 @@
 error: no rules expected the token `,`
- --> $DIR/unexpected_comma.rs:5:17
+ --> $DIR/unexpected_comma.rs:4:17
   |
-5 |     json!({ "a" , "b": true });
+4 |     json!({ "a" , "b": true });
   |                 ^ no rules expected this token in macro call
 
 error: aborting due to previous error