coverage: Test for column numbers involving non-ASCII characters

tests/coverage/unicode.cov-map

@@ -0,0 +1,53 @@
+Function name: unicode::main
+Raw bytes (67): 0x[01, 01, 09, 01, 05, 03, 05, 1e, 0d, 22, 09, 03, 05, 11, 1b, 1e, 0d, 22, 09, 03, 05, 09, 01, 0e, 01, 00, 0b, 05, 01, 09, 00, 0b, 03, 00, 0f, 00, 18, 05, 00, 19, 00, 24, 22, 02, 08, 00, 13, 09, 00, 17, 00, 22, 11, 00, 23, 02, 06, 1b, 02, 06, 00, 07, 17, 02, 05, 01, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 9
+- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
+- expression 1 operands: lhs = Expression(0, Add), rhs = Counter(1)
+- expression 2 operands: lhs = Expression(7, Sub), rhs = Counter(3)
+- expression 3 operands: lhs = Expression(8, Sub), rhs = Counter(2)
+- expression 4 operands: lhs = Expression(0, Add), rhs = Counter(1)
+- expression 5 operands: lhs = Counter(4), rhs = Expression(6, Add)
+- expression 6 operands: lhs = Expression(7, Sub), rhs = Counter(3)
+- expression 7 operands: lhs = Expression(8, Sub), rhs = Counter(2)
+- expression 8 operands: lhs = Expression(0, Add), rhs = Counter(1)
+Number of file 0 mappings: 9
+- Code(Counter(0)) at (prev + 14, 1) to (start + 0, 11)
+- Code(Counter(1)) at (prev + 1, 9) to (start + 0, 11)
+- Code(Expression(0, Add)) at (prev + 0, 15) to (start + 0, 24)
+    = (c0 + c1)
+- Code(Counter(1)) at (prev + 0, 25) to (start + 0, 36)
+- Code(Expression(8, Sub)) at (prev + 2, 8) to (start + 0, 19)
+    = ((c0 + c1) - c1)
+- Code(Counter(2)) at (prev + 0, 23) to (start + 0, 34)
+- Code(Counter(4)) at (prev + 0, 35) to (start + 2, 6)
+- Code(Expression(6, Add)) at (prev + 2, 6) to (start + 0, 7)
+    = ((((c0 + c1) - c1) - c2) + c3)
+- Code(Expression(5, Add)) at (prev + 2, 5) to (start + 1, 2)
+    = (c4 + ((((c0 + c1) - c1) - c2) + c3))
+
+Function name: unicode::サビ
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 1e, 12, 00, 14]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 30, 18) to (start + 0, 20)
+
+Function name: unicode::他 (unused)
+Raw bytes (9): 0x[01, 01, 00, 01, 00, 1e, 15, 00, 1f]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Zero) at (prev + 30, 21) to (start + 0, 31)
+
+Function name: unicode::申し訳ございません
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 18, 01, 02, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 24, 1) to (start + 2, 2)
+

tests/coverage/unicode.rs

@@ -0,0 +1,36 @@
+// edition: 2021
+// ignore-mode-coverage-run - `llvm-cov` fails due to incorrectly-split UTF-8
+// llvm-cov-flags: --use-color
+
+// Check that column numbers are denoted in bytes, so that they don't cause
+// `llvm-cov` to fail or emit malformed output.
+//
+// Note that when `llvm-cov` prints ^ arrows on a subsequent line, it simply
+// inserts one space character for each "column", with no understanding of
+// Unicode or character widths. So those arrows will tend to be misaligned
+// for non-ASCII source code, regardless of whether column numbers are code
+// points or bytes.
+
+fn main() {
+    for _İ in 'А'..='Я' { /* Я */ }
+
+    if 申し訳ございません() && 申し訳ございません() {
+        println!("true");
+    }
+
+    サビ();
+}
+
+fn 申し訳ございません() -> bool {
+    std::hint::black_box(false)
+}
+
+macro_rules! macro_that_defines_a_function {
+    (fn $名:ident () $体:tt) => {
+        fn $名 () $体 fn 他 () {}
+    }
+}
+
+macro_that_defines_a_function! {
+    fn サビ() {}
+}