Delete line if suggestion would replace it with an empty line

[clubby789]

Fixes #120296

[rustbot]

r? @petrochenkov

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[estebank]

Although this is a way to address this specific issue, it might be a better idea to modify rustc_errors::json::DiagnosticSpan::from_span_full to have this logic of checking "does this span end on the last char of a line, followed by \n? if extend the span by one byte". Doing it there doesn't change how the diff is shown in diagnostics, but aids rustfix not have to care about this and doesn't require us to address these kind of spans in every suggestion we produce.

[clubby789]

Doing that globally seems to break a lot of .fixed tests:

diff --git a/tests/ui/binop/false-binop-caused-by-missing-semi.fixed b/tests/ui/binop/false-binop-caused-by-missing-semi.fixed
index b47372c9064..441fad80c8f 100644
--- a/tests/ui/binop/false-binop-caused-by-missing-semi.fixed
+++ b/tests/ui/binop/false-binop-caused-by-missing-semi.fixed
@@ -3,8 +3,7 @@ fn foo() {}
 fn main() {
     let mut y = 42;
     let x = &mut y;
-    foo();
-    *x = 0;  //~ ERROR invalid left-hand side of assignment
+    foo();    *x = 0;  //~ ERROR invalid left-hand side of assignment
     let _ = x;
     println!("{y}");
 }
diff --git a/tests/ui/block-result/consider-removing-last-semi.fixed b/tests/ui/block-result/consider-removing-last-semi.fixed
index 36a769fe529..931a5440b79 100644
--- a/tests/ui/block-result/consider-removing-last-semi.fixed
+++ b/tests/ui/block-result/consider-removing-last-semi.fixed
@@ -2,19 +2,16 @@
 
 pub fn f() -> String {  //~ ERROR mismatched types
     0u8;
-    "bla".to_string()
-}
+    "bla".to_string()}
 
 pub fn g() -> String {  //~ ERROR mismatched types
     "this won't work".to_string();
-    "removeme".to_string()
-}
+    "removeme".to_string()}
 
 pub fn macro_tests() -> u32 {  //~ ERROR mismatched types
     macro_rules! mac {
         () => (1);
     }
-    mac!()
-}
+    mac!()}```

[estebank]

@clubby789 what happens if you only do the span extension if the replacement is ""? An alternative heuristic could be to see if the start column is 0 as well...

[clubby789]

Catches a lot more cases 👀 Good idea!

[clubby789]

Actually this could do with some improvement
@rustbot author

[rustbot]

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

[bors]

☔ The latest upstream changes (presumably #121810) made this pull request unmergeable. Please resolve the merge conflicts.

[estebank]

please rebase and I'll approve

[clubby789]

@rustbot ready

[estebank]

@bors r+

[bors]

📌 Commit 367126d has been approved by estebank

It is now in the queue for this repository.