fix: #6558 don't try to repair invalid self-imports.

Attempts break idempotence.

Author: MarcusGrass

src/imports.rs

@@ -557,20 +557,9 @@ impl UseTree {
                 self.path = vec![];
                 return self;
             }
-            UseSegmentKind::Slf(None) if self.path.is_empty() && self.visibility.is_some() => {
-                self.path = vec![];
-                return self;
-            }
             _ => (),
         }
 
-        // Normalise foo::self -> foo.
-        if let UseSegmentKind::Slf(None) = last.kind {
-            if !self.path.is_empty() {
-                return self;
-            }
-        }
-
         // Normalise foo::self as bar -> foo as bar.
         if let UseSegmentKind::Slf(_) = last.kind {
             if let Some(UseSegment {

tests/source/imports/imports.rs

@@ -23,8 +23,10 @@ pub use rustc_ast::ast::{Expr_, Expr, ExprAssign, ExprCall, ExprMethodCall, Expr
 
 use rustc_ast::some::{};
 
+// compilation error that will (and should) be ignored by rustfmt #6558
 use self;
 use std::io::{self};
+// compilation error that will (and should) be ignored by rustfmt #6558
 use std::io::self;
 
 mod Foo {

tests/source/imports/imports_granularity_default-with-dups.rs

@@ -1,6 +1,7 @@
 use crate::lexer;
 use crate::lexer::tokens::TokenData;
 use crate::lexer::{tokens::TokenData};
+// compilation error that will (and should) be ignored by rustfmt #6558
 use crate::lexer::self;
 use crate::lexer::{self};
 use crate::lexer::{self, tokens::TokenData};

tests/source/issue_6558.rs

@@ -0,0 +1,5 @@
+// Removing `self` breaks idempotence, leaving it causes a compilation error
+// which the user should be made aware of #6558
+use self;
+use self::self;
+use self::self::self;

tests/target/imports/imports.rs

@@ -27,8 +27,11 @@ use rustc_ast::{self};
 use Foo::{Bar, Baz};
 use {Bar /* comment */, /* Pre-comment! */ Foo};
 
-use std::io;
+// compilation error that will (and should) be ignored by rustfmt #6558
+use self;
 use std::io::{self};
+// compilation error that will (and should) be ignored by rustfmt #6558
+use std::io::self;
 
 mod Foo {
     pub use rustc_ast::ast::{

tests/target/imports/imports_granularity_default-with-dups.rs

@@ -1,6 +1,7 @@
 use crate::lexer;
-use crate::lexer;
 use crate::lexer::tokens::TokenData;
 use crate::lexer::tokens::TokenData;
+// compilation error that will (and should) be ignored by rustfmt #6558
+use crate::lexer::self;
 use crate::lexer::{self};
 use crate::lexer::{self, tokens::TokenData};

tests/target/issue_6558.rs

@@ -0,0 +1,5 @@
+// Removing `self` breaks idempotence, leaving it causes a compilation error
+// which the user should be made aware of #6558
+use self;
+use self::self;
+use self::self::self;