Avoid ICE of attempt to add with overflow in emitter

compiler/rustc_errors/src/lib.rs

@@ -331,7 +331,7 @@ impl CodeSuggestion {
  });
  buf.push_str(&part.snippet);
  let cur_hi = sm.lookup_char_pos(part.span.hi());
- if cur_hi.line == cur_lo.line {
+ if cur_hi.line == cur_lo.line && !part.snippet.is_empty() {
  // Account for the difference between the width of the current code and the
  // snippet being suggested, so that the *later* suggestions are correctly
  // aligned on the screen.

tests/ui/suggestions/issue-109396.rs

@@ -0,0 +1,12 @@
+fn main() {
+ {
+ let mut mutex = std::mem::zeroed(
+ //~^ ERROR this function takes 0 arguments but 4 arguments were supplied
+ file.as_raw_fd(),
+ //~^ ERROR expected value, found macro `file`
+ 0,
+ 0,
+ 0,
+ );
+ }
+}

tests/ui/suggestions/issue-109396.stderr

@@ -0,0 +1,34 @@
+error[E0423]: expected value, found macro `file`
+ --> $DIR/issue-109396.rs:5:13
+ |
+LL | file.as_raw_fd(),
+ | ^^^^ not a value
+
+error[E0061]: this function takes 0 arguments but 4 arguments were supplied
+ --> $DIR/issue-109396.rs:3:25
+ |
+LL | let mut mutex = std::mem::zeroed(
+ | ^^^^^^^^^^^^^^^^
+LL |
+LL | file.as_raw_fd(),
+ | ---------------- unexpected argument
+LL |
+LL | 0,
+ | - unexpected argument of type `{integer}`
+LL | 0,
+ | - unexpected argument of type `{integer}`
+LL | 0,
+ | - unexpected argument of type `{integer}`
+ |
+note: function defined here
+ --> $SRC_DIR/core/src/mem/mod.rs:LL:COL
+help: remove the extra arguments
+ |
+LL - file.as_raw_fd(),
+LL + ,
+ |
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0061, E0423.
+For more information about an error, try `rustc --explain E0061`.