fix: default to all targets when using --edition and --edition-idioms in cargo fix (#15192)

### What does this PR try to resolve?

Close https://github.com/rust-lang/cargo/issues/13527

As we discussed, `cargo fix` should use the default target selection
with `cargo check`.

In this PR, I modified `cargo fix` to no longer use all targets by
default. For `cargo fix --edition` and `cargo fix --edition-idioms`, it
will retain the old behavior and select all targets.

### How should we test and review this PR?

Unit tests

### Additional information

src/bin/cargo/commands/fix.rs

@@ -81,8 +81,11 @@ pub fn exec(gctx: &mut GlobalContext, args: &ArgMatches) -> CliResult {
 
     let mut opts = args.compile_options(gctx, mode, Some(&ws), ProfileChecking::LegacyTestOnly)?;
 
-    if !opts.filter.is_specific() {
+    let edition = args.flag("edition") || args.flag("edition-idioms");
-        // cargo fix with no target selection implies `--all-targets`.
+    if !opts.filter.is_specific() && edition {
+        // When `cargo fix` is run without specifying targets but with `--edition` or `--edition-idioms`,
+        // it should default to fixing all targets.
+        // See: https://github.com/rust-lang/cargo/issues/13527
         opts.filter = ops::CompileFilter::new_all_targets();
     }
 

tests/testsuite/fix.rs

@@ -197,6 +197,103 @@ fn prepare_for_2018() {
         .contains("let x = crate::foo::FOO;"));
 }
 
+#[cargo_test]
+fn fix_tests_with_edition() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.1.0"
+                edition = "2018"
+            "#,
+        )
+        .file(
+            "src/lib.rs",
+            r#"
+                #![allow(ellipsis_inclusive_range_patterns)]
+                pub fn foo() {}
+
+                #[cfg(test)]
+                mod tests {
+                    #[test]
+                    fn it_works() {
+                        f();
+                    }
+                    fn f() -> bool {
+                        let x = 123;
+                        match x {
+                            0...100 => true,
+                            _ => false,
+                        }
+                    }
+                }
+            "#,
+        )
+        .build();
+
+    p.cargo("fix --edition --allow-no-vcs")
+        .with_stderr_data(str![[r#"
+[MIGRATING] Cargo.toml from 2018 edition to 2021
+[CHECKING] foo v0.1.0 ([ROOT]/foo)
+[MIGRATING] src/lib.rs from 2018 edition to 2021
+[FIXED] src/lib.rs (1 fix)
+[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
+
+"#]])
+        .with_stdout_data("")
+        .run();
+    // Check that the test is fixed.
+    assert!(p.read_file("src/lib.rs").contains(r#"0..=100 => true,"#));
+}
+
+#[cargo_test]
+fn fix_tests_with_edition_idioms() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = 'foo'
+                version = '0.1.0'
+                edition = '2018'
+            "#,
+        )
+        .file(
+            "src/lib.rs",
+            r#"
+                pub fn foo() {}
+
+                #[cfg(test)]
+                mod tests {
+                    #[test]
+                    fn it_works() {
+                        f();
+                    }
+
+                    use std::any::Any;
+                    pub fn f() {
+                        let _x: Box<Any> = Box::new(3);
+                    }
+                }
+            "#,
+        )
+        .build();
+
+    p.cargo("fix --edition-idioms --allow-no-vcs")
+        .with_stderr_data(str![[r#"
+[CHECKING] foo v0.1.0 ([ROOT]/foo)
+[FIXED] src/lib.rs (1 fix)
+[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
+
+"#]])
+        .with_stdout_data("")
+        .run();
+    // Check that the test is fixed.
+    assert!(p.read_file("src/lib.rs").contains("Box<dyn Any>"));
+}
+
 #[cargo_test]
 fn local_paths() {
     let p = project()
@@ -708,7 +805,7 @@ fn does_not_warn_about_dirty_ignored_files() {
 }
 
 #[cargo_test]
-fn fix_all_targets_by_default() {
+fn do_not_fix_tests_by_default() {
     let p = project()
         .file("src/lib.rs", "pub fn foo() { let mut x = 3; let _ = x; }")
         .file("tests/foo.rs", "pub fn foo() { let mut x = 3; let _ = x; }")
@@ -717,7 +814,7 @@ fn fix_all_targets_by_default() {
         .env("__CARGO_FIX_YOLO", "1")
         .run();
     assert!(!p.read_file("src/lib.rs").contains("let mut x"));
-    assert!(!p.read_file("tests/foo.rs").contains("let mut x"));
+    assert!(p.read_file("tests/foo.rs").contains("let mut x"));
 }
 
 #[cargo_test]
@@ -1330,7 +1427,6 @@ fn fix_to_broken_code() {
     p.cargo("fix --allow-no-vcs --broken-code")
         .cwd("bar")
         .env("RUSTC", p.root().join("foo/target/debug/foo"))
-        .with_status(101)
         .with_stderr_data(str![[r#"
 ...
 [WARNING] failed to automatically apply fixes suggested by rustc to crate `bar`