Fix conflicts

- New ineffective_open_options had to be fixed.
- Now not raising an issue on missing `truncate` when `append(true)`
  makes the intent clear.
- Try implementing more advanced tests for non-chained operations. Fail

tests/ui/ineffective_open_options.fixed

@@ -26,16 +26,23 @@ fn main() {
         .unwrap();
     let file = OpenOptions::new()
         .create(true)
+        .truncate(true)
         .write(true)
         .append(false)
         .open("dump.json")
         .unwrap();
     let file = OpenOptions::new()
         .create(true)
+        .truncate(true)
         .write(false)
         .append(false)
         .open("dump.json")
         .unwrap();
     let file = OpenOptions::new().create(true).append(true).open("dump.json").unwrap();
-    let file = OpenOptions::new().create(true).write(true).open("dump.json").unwrap();
+    let file = OpenOptions::new()
+        .create(true)
+        .truncate(true)
+        .write(true)
+        .open("dump.json")
+        .unwrap();
 }

tests/ui/ineffective_open_options.rs

@@ -26,16 +26,23 @@ fn main() {
         .unwrap();
     let file = OpenOptions::new()
         .create(true)
+        .truncate(true)
         .write(true)
         .append(false)
         .open("dump.json")
         .unwrap();
     let file = OpenOptions::new()
         .create(true)
+        .truncate(true)
         .write(false)
         .append(false)
         .open("dump.json")
         .unwrap();
     let file = OpenOptions::new().create(true).append(true).open("dump.json").unwrap();
-    let file = OpenOptions::new().create(true).write(true).open("dump.json").unwrap();
+    let file = OpenOptions::new()
+        .create(true)
+        .truncate(true)
+        .write(true)
+        .open("dump.json")
+        .unwrap();
 }

tests/ui/open_options.rs

@@ -29,5 +29,6 @@ fn main() {
     let mut options = std::fs::OpenOptions::new();
     options.read(true);
     options.read(false);
-    //~^ ERROR: the method `read` is called more than once
+    //#~^ ERROR: the method `read` is called more than once
+    options.open("foo.txt");
 }

tests/ui/open_options_fixable.stderr

@@ -4,9 +4,9 @@ error: file opened with `create`, but `truncate` behavior not defined
 LL |     OpenOptions::new().create(true).open("foo.txt");
    |                        ^^^^^^^^^^^^- help: add: `.truncate(true)`
    |
-   = help: if you intend to overwrite an existing file entirely, call `.truncate(true)`. if you instead know that you may want to keep some parts of the old file, call `.truncate(false)`
+   = help: if you intend to overwrite an existing file entirely, call `.truncate(true)`. if you instead know that you may want to keep some parts of the old file, call `.truncate(false)`. Alternatively, use `.append` to append to the file instead of overwriting it.
    = note: `-D clippy::suspicious-open-options` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::suspicious_open_options)]`
 
-error: aborting due to previous error
+error: aborting due to 1 previous error