Auto merge of rust-lang#12374 - Alexendoo:duplicate-diagnostics, r=Manishearth

Show duplicate diagnostics in UI tests by default

Duplicated diagnostics can indicate where redundant work is being done, this PR doesn't fix any of that but does indicate in which tests they're occurring for future investigation or to catch issues in future lints

changelog: none

Author: bors

tests/compile-test.rs

@@ -138,6 +138,7 @@ fn base_config(test_dir: &str) -> (Config, Args) {
             "-Aunused",
             "-Ainternal_features",
             "-Zui-testing",
+            "-Zdeduplicate-diagnostics=no",
             "-Dwarnings",
             &format!("-Ldependency={}", deps_path.display()),
         ]

tests/ui-internal/custom_ice_message.stderr

@@ -8,7 +8,7 @@ note: we would appreciate a bug report: https://github.com/rust-lang/rust-clippy
 
 note: rustc <version> running on <target>
 
-note: compiler flags: -Z ui-testing
+note: compiler flags: -Z ui-testing -Z deduplicate-diagnostics=no
 
 note: Clippy version: foo
 

tests/ui/assign_ops2.rs

@@ -1,4 +1,6 @@
 //@no-rustfix: overlapping suggestions
+//@compile-flags: -Zdeduplicate-diagnostics=yes
+
 #![allow(clippy::uninlined_format_args)]
 
 #[allow(unused_assignments)]

tests/ui/assign_ops2.stderr

@@ -1,5 +1,5 @@
 error: variable appears on both sides of an assignment operation
-  --> tests/ui/assign_ops2.rs:8:5
+  --> tests/ui/assign_ops2.rs:10:5
    |
 LL |     a += a + 1;
    |     ^^^^^^^^^^
@@ -16,7 +16,7 @@ LL |     a = a + a + 1;
    |     ~~~~~~~~~~~~~
 
 error: variable appears on both sides of an assignment operation
-  --> tests/ui/assign_ops2.rs:11:5
+  --> tests/ui/assign_ops2.rs:13:5
    |
 LL |     a += 1 + a;
    |     ^^^^^^^^^^
@@ -31,7 +31,7 @@ LL |     a = a + 1 + a;
    |     ~~~~~~~~~~~~~
 
 error: variable appears on both sides of an assignment operation
-  --> tests/ui/assign_ops2.rs:13:5
+  --> tests/ui/assign_ops2.rs:15:5
    |
 LL |     a -= a - 1;
    |     ^^^^^^^^^^
@@ -46,7 +46,7 @@ LL |     a = a - (a - 1);
    |     ~~~~~~~~~~~~~~~
 
 error: variable appears on both sides of an assignment operation
-  --> tests/ui/assign_ops2.rs:15:5
+  --> tests/ui/assign_ops2.rs:17:5
    |
 LL |     a *= a * 99;
    |     ^^^^^^^^^^^
@@ -61,7 +61,7 @@ LL |     a = a * a * 99;
    |     ~~~~~~~~~~~~~~
 
 error: variable appears on both sides of an assignment operation
-  --> tests/ui/assign_ops2.rs:17:5
+  --> tests/ui/assign_ops2.rs:19:5
    |
 LL |     a *= 42 * a;
    |     ^^^^^^^^^^^
@@ -76,7 +76,7 @@ LL |     a = a * 42 * a;
    |     ~~~~~~~~~~~~~~
 
 error: variable appears on both sides of an assignment operation
-  --> tests/ui/assign_ops2.rs:19:5
+  --> tests/ui/assign_ops2.rs:21:5
    |
 LL |     a /= a / 2;
    |     ^^^^^^^^^^
@@ -91,7 +91,7 @@ LL |     a = a / (a / 2);
    |     ~~~~~~~~~~~~~~~
 
 error: variable appears on both sides of an assignment operation
-  --> tests/ui/assign_ops2.rs:21:5
+  --> tests/ui/assign_ops2.rs:23:5
    |
 LL |     a %= a % 5;
    |     ^^^^^^^^^^
@@ -106,7 +106,7 @@ LL |     a = a % (a % 5);
    |     ~~~~~~~~~~~~~~~
 
 error: variable appears on both sides of an assignment operation
-  --> tests/ui/assign_ops2.rs:23:5
+  --> tests/ui/assign_ops2.rs:25:5
    |
 LL |     a &= a & 1;
    |     ^^^^^^^^^^
@@ -121,7 +121,7 @@ LL |     a = a & a & 1;
    |     ~~~~~~~~~~~~~
 
 error: variable appears on both sides of an assignment operation
-  --> tests/ui/assign_ops2.rs:25:5
+  --> tests/ui/assign_ops2.rs:27:5
    |
 LL |     a *= a * a;
    |     ^^^^^^^^^^
@@ -136,7 +136,7 @@ LL |     a = a * a * a;
    |     ~~~~~~~~~~~~~
 
 error: manual implementation of an assign operation
-  --> tests/ui/assign_ops2.rs:63:5
+  --> tests/ui/assign_ops2.rs:65:5
    |
 LL |     buf = buf + cows.clone();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `buf += cows.clone()`

tests/ui/else_if_without_else.rs

@@ -1,3 +1,5 @@
+//@compile-flags: -Zdeduplicate-diagnostics=yes
+
 #![warn(clippy::all)]
 #![warn(clippy::else_if_without_else)]
 

tests/ui/else_if_without_else.stderr

@@ -1,5 +1,5 @@
 error: `if` expression with an `else if`, but without a final `else`
-  --> tests/ui/else_if_without_else.rs:45:12
+  --> tests/ui/else_if_without_else.rs:47:12
    |
 LL |       } else if bla2() {
    |  ____________^
@@ -13,7 +13,7 @@ LL | |     }
    = help: to override `-D warnings` add `#[allow(clippy::else_if_without_else)]`
 
 error: `if` expression with an `else if`, but without a final `else`
-  --> tests/ui/else_if_without_else.rs:54:12
+  --> tests/ui/else_if_without_else.rs:56:12
    |
 LL |       } else if bla3() {
    |  ____________^

tests/ui/identity_op.fixed

@@ -1,3 +1,5 @@
+//@compile-flags: -Zdeduplicate-diagnostics=yes
+
 #![warn(clippy::identity_op)]
 #![allow(unused)]
 #![allow(
@@ -134,7 +136,7 @@ fn main() {
     //~^ ERROR: this operation has no effect
     f(if b { 1 } else { 2 } + 3);
     //~^ ERROR: this operation has no effect
-    
+
     const _: i32 = { 2 * 4 } + 3;
     //~^ ERROR: this operation has no effect
     const _: i32 = { 1 + 2 * 3 } + 3;

tests/ui/identity_op.rs

@@ -1,3 +1,5 @@
+//@compile-flags: -Zdeduplicate-diagnostics=yes
+
 #![warn(clippy::identity_op)]
 #![allow(unused)]
 #![allow(
@@ -134,7 +136,7 @@ fn main() {
     //~^ ERROR: this operation has no effect
     f(0 + if b { 1 } else { 2 } + 3);
     //~^ ERROR: this operation has no effect
-    
+
     const _: i32 = { 2 * 4 } + 0 + 3;
     //~^ ERROR: this operation has no effect
     const _: i32 = 0 + { 1 + 2 * 3 } + 3;