Fix wrong span for hightlight for duplicated diff lines

Author: chenyukang

compiler/rustc_errors/src/emitter.rs

@@ -2412,7 +2412,7 @@ impl HumanEmitter {
                             // too bad to begin with, so we side-step that issue here.
                             for (i, line) in snippet.lines().enumerate() {
                                 let line = normalize_whitespace(line);
-                                let row = row_num - 2 - (newlines - i - 1);
+                                let row = (row_num - 2 - (newlines - i - 1)).max(2);
                                 // On the first line, we highlight between the start of the part
                                 // span, and the end of that line.
                                 // On the last line, we highlight between the start of the line, and

tests/ui/argument-suggestions/wrong-highlight-span-extra-arguments-147070.rs

@@ -0,0 +1,26 @@
+struct Thingie;
+
+impl Thingie {
+    pub(crate) fn new(
+        _a: String,
+        _b: String,
+        _c: String,
+        _d: String,
+        _e: String,
+        _f: String,
+    ) -> Self {
+        unimplemented!()
+    }
+}
+
+fn main() {
+    let foo = Thingie::new( //~ ERROR: this function takes 6 arguments but 7 arguments were supplied
+        String::from(""),
+        String::from(""),
+        String::from(""),
+        String::from(""),
+        String::from(""),
+        String::from(""),
+        String::from(""),
+    );
+}

tests/ui/argument-suggestions/wrong-highlight-span-extra-arguments-147070.stderr

@@ -0,0 +1,22 @@
+error[E0061]: this function takes 6 arguments but 7 arguments were supplied
+  --> $DIR/wrong-highlight-span-extra-arguments-147070.rs:17:15
+   |
+LL |     let foo = Thingie::new(
+   |               ^^^^^^^^^^^^
+...
+LL |         String::from(""),
+   |         ---------------- unexpected argument #7 of type `String`
+   |
+note: associated function defined here
+  --> $DIR/wrong-highlight-span-extra-arguments-147070.rs:4:19
+   |
+LL |     pub(crate) fn new(
+   |                   ^^^
+help: remove the extra argument
+   |
+LL -         String::from(""),
+   |
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0061`.