With the improved escape sequence parser, it becomes easy to also improve

diagnostics.  Distinguish "incomplete escape sequence", "invalid special
character", and "unknown special character" from the generic "invalid
escape sequence", also promoting them from WARNING to ERROR because
incomplete escape sequences are severe syntax violations and because
encountering an invalid or unknown special character makes it likely
that part of the document content intended by the authors gets lost.

5 files changed, 40 insertions, 40 deletions

diff --git a/regress/roff/esc/B.out_lint b/regress/roff/esc/B.out_lint
index f52270a4..fbaded65 100644
--- a/regress/roff/esc/B.out_lint
+++ b/regress/roff/esc/B.out_lint
@@ -1 +1 @@
-mandoc: B.in:37:23: WARNING: invalid escape sequence: \B'1+1
+mandoc: B.in:37:23: ERROR: incomplete escape sequence: \B'1+1
diff --git a/regress/roff/esc/ignore.out_lint b/regress/roff/esc/ignore.out_lint
index 16d64a97..ddbc8d6e 100644
--- a/regress/roff/esc/ignore.out_lint
+++ b/regress/roff/esc/ignore.out_lint
@@ -1,14 +1,14 @@
-mandoc: ignore.in:7:36: WARNING: invalid escape sequence: \[%]
-mandoc: ignore.in:8:35: WARNING: invalid escape sequence: \[&]
-mandoc: ignore.in:9:51: WARNING: invalid escape sequence: \[)]
-mandoc: ignore.in:10:37: WARNING: invalid escape sequence: \[,]
-mandoc: ignore.in:11:38: WARNING: invalid escape sequence: \[/]
-mandoc: ignore.in:12:28: WARNING: invalid escape sequence: \[^]
-mandoc: ignore.in:13:17: WARNING: invalid escape sequence: \[a]
-mandoc: ignore.in:14:25: WARNING: invalid escape sequence: \[d]
-mandoc: ignore.in:15:25: WARNING: invalid escape sequence: \[t]
-mandoc: ignore.in:16:33: WARNING: invalid escape sequence: \[u]
-mandoc: ignore.in:17:20: WARNING: invalid escape sequence: \[{]
-mandoc: ignore.in:18:25: WARNING: invalid escape sequence: \[|]
-mandoc: ignore.in:19:20: WARNING: invalid escape sequence: \[}]
-mandoc: ignore.in:23:56: WARNING: invalid escape sequence: \s-
+mandoc: ignore.in:7:36: ERROR: invalid special character: \[%]
+mandoc: ignore.in:8:35: ERROR: invalid special character: \[&]
+mandoc: ignore.in:9:51: ERROR: invalid special character: \[)]
+mandoc: ignore.in:10:37: ERROR: invalid special character: \[,]
+mandoc: ignore.in:11:38: ERROR: invalid special character: \[/]
+mandoc: ignore.in:12:28: ERROR: invalid special character: \[^]
+mandoc: ignore.in:13:17: ERROR: invalid special character: \[a]
+mandoc: ignore.in:14:25: ERROR: invalid special character: \[d]
+mandoc: ignore.in:15:25: ERROR: invalid special character: \[t]
+mandoc: ignore.in:16:33: ERROR: invalid special character: \[u]
+mandoc: ignore.in:17:20: ERROR: invalid special character: \[{]
+mandoc: ignore.in:18:25: ERROR: invalid special character: \[|]
+mandoc: ignore.in:19:20: ERROR: invalid special character: \[}]
+mandoc: ignore.in:23:56: ERROR: incomplete escape sequence: \s-
diff --git a/regress/roff/esc/invalid.out_lint b/regress/roff/esc/invalid.out_lint
index baef3176..ff52893f 100644
--- a/regress/roff/esc/invalid.out_lint
+++ b/regress/roff/esc/invalid.out_lint
@@ -1,43 +1,43 @@
 mandoc: invalid.in:7:8: WARNING: undefined escape, printing literally: \+
-mandoc: invalid.in:7:11: WARNING: invalid escape sequence: \[+]
+mandoc: invalid.in:7:11: ERROR: invalid special character: \[+]
 mandoc: invalid.in:8:13: WARNING: undefined escape, printing literally: \;
-mandoc: invalid.in:8:16: WARNING: invalid escape sequence: \[;]
+mandoc: invalid.in:8:16: ERROR: invalid special character: \[;]
 mandoc: invalid.in:9:13: WARNING: undefined escape, printing literally: \<
-mandoc: invalid.in:9:16: WARNING: invalid escape sequence: \[<]
+mandoc: invalid.in:9:16: ERROR: invalid special character: \[<]
 mandoc: invalid.in:10:12: WARNING: undefined escape, printing literally: \=
-mandoc: invalid.in:10:15: WARNING: invalid escape sequence: \[=]
+mandoc: invalid.in:10:15: ERROR: invalid special character: \[=]
 mandoc: invalid.in:11:16: WARNING: undefined escape, printing literally: \>
-mandoc: invalid.in:11:19: WARNING: invalid escape sequence: \[>]
+mandoc: invalid.in:11:19: ERROR: invalid special character: \[>]
 mandoc: invalid.in:12:6: WARNING: undefined escape, printing literally: \@
-mandoc: invalid.in:12:9: WARNING: invalid escape sequence: \[@]
+mandoc: invalid.in:12:9: ERROR: invalid special character: \[@]
 mandoc: invalid.in:13:18: WARNING: undefined escape, printing literally: \]
-mandoc: invalid.in:14:16: WARNING: invalid escape sequence: \[{]
-mandoc: invalid.in:14:21: WARNING: invalid escape sequence: \[}]
+mandoc: invalid.in:14:16: ERROR: invalid special character: \[{]
+mandoc: invalid.in:14:21: ERROR: invalid special character: \[}]
 mandoc: invalid.in:15:9: WARNING: undefined escape, printing literally: \1
-mandoc: invalid.in:15:12: WARNING: invalid escape sequence: \[1]
+mandoc: invalid.in:15:12: ERROR: invalid special character: \[1]
 mandoc: invalid.in:16:5: WARNING: undefined escape, printing literally: \G
-mandoc: invalid.in:16:8: WARNING: invalid escape sequence: \[G]
+mandoc: invalid.in:16:8: ERROR: invalid special character: \[G]
 mandoc: invalid.in:17:5: WARNING: undefined escape, printing literally: \I
-mandoc: invalid.in:17:8: WARNING: invalid escape sequence: \[I]
+mandoc: invalid.in:17:8: ERROR: invalid special character: \[I]
 mandoc: invalid.in:18:5: WARNING: undefined escape, printing literally: \i
-mandoc: invalid.in:18:8: WARNING: invalid escape sequence: \[i]
+mandoc: invalid.in:18:8: ERROR: invalid special character: \[i]
 mandoc: invalid.in:19:5: WARNING: undefined escape, printing literally: \J
-mandoc: invalid.in:19:8: WARNING: invalid escape sequence: \[J]
+mandoc: invalid.in:19:8: ERROR: invalid special character: \[J]
 mandoc: invalid.in:20:5: WARNING: undefined escape, printing literally: \j
-mandoc: invalid.in:20:8: WARNING: invalid escape sequence: \[j]
+mandoc: invalid.in:20:8: ERROR: invalid special character: \[j]
 mandoc: invalid.in:21:5: WARNING: undefined escape, printing literally: \K
-mandoc: invalid.in:21:8: WARNING: invalid escape sequence: \[K]
+mandoc: invalid.in:21:8: ERROR: invalid special character: \[K]
 mandoc: invalid.in:22:5: WARNING: undefined escape, printing literally: \P
-mandoc: invalid.in:22:8: WARNING: invalid escape sequence: \[P]
+mandoc: invalid.in:22:8: ERROR: invalid special character: \[P]
 mandoc: invalid.in:23:5: WARNING: undefined escape, printing literally: \Q
-mandoc: invalid.in:23:8: WARNING: invalid escape sequence: \[Q]
+mandoc: invalid.in:23:8: ERROR: invalid special character: \[Q]
 mandoc: invalid.in:24:5: WARNING: undefined escape, printing literally: \q
-mandoc: invalid.in:24:8: WARNING: invalid escape sequence: \[q]
+mandoc: invalid.in:24:8: ERROR: invalid special character: \[q]
 mandoc: invalid.in:25:5: WARNING: undefined escape, printing literally: \T
-mandoc: invalid.in:25:8: WARNING: invalid escape sequence: \[T]
+mandoc: invalid.in:25:8: ERROR: invalid special character: \[T]
 mandoc: invalid.in:26:5: WARNING: undefined escape, printing literally: \U
-mandoc: invalid.in:26:8: WARNING: invalid escape sequence: \[U]
+mandoc: invalid.in:26:8: ERROR: invalid special character: \[U]
 mandoc: invalid.in:27:5: WARNING: undefined escape, printing literally: \W
-mandoc: invalid.in:27:8: WARNING: invalid escape sequence: \[W]
+mandoc: invalid.in:27:8: ERROR: invalid special character: \[W]
 mandoc: invalid.in:28:5: WARNING: undefined escape, printing literally: \y
-mandoc: invalid.in:28:8: WARNING: invalid escape sequence: \[y]
+mandoc: invalid.in:28:8: ERROR: invalid special character: \[y]
diff --git a/regress/roff/esc/unsupp.out_lint b/regress/roff/esc/unsupp.out_lint
index fae97c81..db7631c6 100644
--- a/regress/roff/esc/unsupp.out_lint
+++ b/regress/roff/esc/unsupp.out_lint
@@ -1,5 +1,5 @@
 mandoc: unsupp.in:7:20: UNSUPP: unsupported escape sequence: \!
-mandoc: unsupp.in:7:23: WARNING: invalid escape sequence: \[!]
+mandoc: unsupp.in:7:23: ERROR: invalid special character: \[!]
 mandoc: unsupp.in:8:17: UNSUPP: unsupported escape sequence: \?
 mandoc: unsupp.in:8:21: UNSUPP: unsupported escape sequence: \?
-mandoc: unsupp.in:8:24: WARNING: invalid escape sequence: \[?]
+mandoc: unsupp.in:8:24: ERROR: invalid special character: \[?]
diff --git a/regress/roff/esc/w.out_lint b/regress/roff/esc/w.out_lint
index d48495c2..11dfbef5 100644
--- a/regress/roff/esc/w.out_lint
+++ b/regress/roff/esc/w.out_lint
@@ -1 +1 @@
-mandoc: w.in:17:15: WARNING: invalid escape sequence: \w'foo
+mandoc: w.in:17:15: ERROR: incomplete escape sequence: \w'foo