Auto merge of #60168 - varkor:tidy-leading-newline, r=alexcrichton

Add a tidy check for leading newlines

This is fairly uncommon, but it can slip through when refactoring (as evidenced by the files with leading newlines here).

12 files changed, 14 insertions, 16 deletions

diff --git a/src/rustc/rustc.rs b/src/rustc/rustc.rs
index 626fceb5814..4a1786f89ed 100644
--- a/src/rustc/rustc.rs
+++ b/src/rustc/rustc.rs
@@ -1,4 +1,3 @@
-
 fn main() {
     // Pull in jemalloc when enabled.
     //
diff --git a/src/test/incremental/change_name_of_static_in_fn.rs b/src/test/incremental/change_name_of_static_in_fn.rs
index 5b27b6808ea..fd16ad2dca4 100644
--- a/src/test/incremental/change_name_of_static_in_fn.rs
+++ b/src/test/incremental/change_name_of_static_in_fn.rs
@@ -1,4 +1,3 @@
-
 // revisions:rpass1 rpass2 rpass3
 
 // See issue #57692.
diff --git a/src/test/run-make-fulldeps/lto-dylib-dep/a_dylib.rs b/src/test/run-make-fulldeps/lto-dylib-dep/a_dylib.rs
index c5a35296f89..e63457e6eb9 100644
--- a/src/test/run-make-fulldeps/lto-dylib-dep/a_dylib.rs
+++ b/src/test/run-make-fulldeps/lto-dylib-dep/a_dylib.rs
@@ -1,4 +1,3 @@
-
 pub fn foo() {
     println!("bar");
 }
diff --git a/src/test/run-make-fulldeps/lto-dylib-dep/main.rs b/src/test/run-make-fulldeps/lto-dylib-dep/main.rs
index af0955e7f35..4fb3c4730b2 100644
--- a/src/test/run-make-fulldeps/lto-dylib-dep/main.rs
+++ b/src/test/run-make-fulldeps/lto-dylib-dep/main.rs
@@ -1,4 +1,3 @@
-
 extern crate a_dylib;
 
 fn main() {
diff --git a/src/test/run-pass/coherence/auxiliary/re_rebalance_coherence_lib.rs b/src/test/run-pass/coherence/auxiliary/re_rebalance_coherence_lib.rs
index c8d027b25c7..41b9d64d5f7 100644
--- a/src/test/run-pass/coherence/auxiliary/re_rebalance_coherence_lib.rs
+++ b/src/test/run-pass/coherence/auxiliary/re_rebalance_coherence_lib.rs
@@ -1,5 +1,4 @@
-
-pub trait Backend{}
+pub trait Backend {}
 pub trait SupportsDefaultKeyword {}
 
 impl SupportsDefaultKeyword for Postgres {}
diff --git a/src/test/ui/coherence/auxiliary/re_rebalance_coherence_lib.rs b/src/test/ui/coherence/auxiliary/re_rebalance_coherence_lib.rs
index c8d027b25c7..41b9d64d5f7 100644
--- a/src/test/ui/coherence/auxiliary/re_rebalance_coherence_lib.rs
+++ b/src/test/ui/coherence/auxiliary/re_rebalance_coherence_lib.rs
@@ -1,5 +1,4 @@
-
-pub trait Backend{}
+pub trait Backend {}
 pub trait SupportsDefaultKeyword {}
 
 impl SupportsDefaultKeyword for Postgres {}
diff --git a/src/test/ui/e0119/conflict-with-std.rs b/src/test/ui/e0119/conflict-with-std.rs
index 6dc81f33dfc..c9db2bab183 100644
--- a/src/test/ui/e0119/conflict-with-std.rs
+++ b/src/test/ui/e0119/conflict-with-std.rs
@@ -1,4 +1,3 @@
-
 use std::marker::PhantomData;
 use std::convert::{TryFrom, AsRef};
 
diff --git a/src/test/ui/e0119/conflict-with-std.stderr b/src/test/ui/e0119/conflict-with-std.stderr
index 8c12b3d0bb9..3e0c71e9074 100644
--- a/src/test/ui/e0119/conflict-with-std.stderr
+++ b/src/test/ui/e0119/conflict-with-std.stderr
@@ -1,5 +1,5 @@
 error[E0119]: conflicting implementations of trait `std::convert::AsRef<Q>` for type `std::boxed::Box<Q>`:
-  --> $DIR/conflict-with-std.rs:6:1
+  --> $DIR/conflict-with-std.rs:5:1
    |
 LL | impl AsRef<Q> for Box<Q> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^
@@ -9,7 +9,7 @@ LL | impl AsRef<Q> for Box<Q> {
              where T: ?Sized;
 
 error[E0119]: conflicting implementations of trait `std::convert::From<S>` for type `S`:
-  --> $DIR/conflict-with-std.rs:13:1
+  --> $DIR/conflict-with-std.rs:12:1
    |
 LL | impl From<S> for S {
    | ^^^^^^^^^^^^^^^^^^
@@ -18,7 +18,7 @@ LL | impl From<S> for S {
            - impl<T> std::convert::From<T> for T;
 
 error[E0119]: conflicting implementations of trait `std::convert::TryFrom<X>` for type `X`:
-  --> $DIR/conflict-with-std.rs:20:1
+  --> $DIR/conflict-with-std.rs:19:1
    |
 LL | impl TryFrom<X> for X {
    | ^^^^^^^^^^^^^^^^^^^^^
diff --git a/src/test/ui/feature-gates/auxiliary/re_rebalance_coherence_lib.rs b/src/test/ui/feature-gates/auxiliary/re_rebalance_coherence_lib.rs
index c8d027b25c7..41b9d64d5f7 100644
--- a/src/test/ui/feature-gates/auxiliary/re_rebalance_coherence_lib.rs
+++ b/src/test/ui/feature-gates/auxiliary/re_rebalance_coherence_lib.rs
@@ -1,5 +1,4 @@
-
-pub trait Backend{}
+pub trait Backend {}
 pub trait SupportsDefaultKeyword {}
 
 impl SupportsDefaultKeyword for Postgres {}
diff --git a/src/test/ui/mod-subitem-as-enum-variant.rs b/src/test/ui/mod-subitem-as-enum-variant.rs
index cd4459ae0ff..9328d1a9045 100644
--- a/src/test/ui/mod-subitem-as-enum-variant.rs
+++ b/src/test/ui/mod-subitem-as-enum-variant.rs
@@ -1,4 +1,3 @@
-
 mod Mod {
     pub struct FakeVariant<T>(pub T);
 }
diff --git a/src/test/ui/mod-subitem-as-enum-variant.stderr b/src/test/ui/mod-subitem-as-enum-variant.stderr
index 72eca588208..d6815c91e5e 100644
--- a/src/test/ui/mod-subitem-as-enum-variant.stderr
+++ b/src/test/ui/mod-subitem-as-enum-variant.stderr
@@ -1,5 +1,5 @@
 error[E0109]: type arguments are not allowed for this type
-  --> $DIR/mod-subitem-as-enum-variant.rs:8:11
+  --> $DIR/mod-subitem-as-enum-variant.rs:7:11
    |
 LL |     Mod::<i32>::FakeVariant(0);
    |           ^^^ type argument not allowed
diff --git a/src/tools/tidy/src/style.rs b/src/tools/tidy/src/style.rs
index a4321cd7571..528a5063ee4 100644
--- a/src/tools/tidy/src/style.rs
+++ b/src/tools/tidy/src/style.rs
@@ -112,6 +112,7 @@ pub fn check(path: &Path, bad: &mut bool) {
         let skip_length = contents.contains("ignore-tidy-linelength");
         let skip_end_whitespace = contents.contains("ignore-tidy-end-whitespace");
         let skip_copyright = contents.contains("ignore-tidy-copyright");
+        let mut leading_new_lines = false;
         let mut trailing_new_lines = 0;
         for (i, line) in contents.split('\n').enumerate() {
             let mut err = |msg: &str| {
@@ -152,11 +153,17 @@ pub fn check(path: &Path, bad: &mut bool) {
                 err(LLVM_UNREACHABLE_INFO);
             }
             if line.is_empty() {
+                if i == 0 {
+                    leading_new_lines = true;
+                }
                 trailing_new_lines += 1;
             } else {
                 trailing_new_lines = 0;
             }
         }
+        if leading_new_lines {
+            tidy_error!(bad, "{}: leading newline", file.display());
+        }
         match trailing_new_lines {
             0 => tidy_error!(bad, "{}: missing trailing newline", file.display()),
             1 | 2 => {}