2 files changed, 40 insertions, 4 deletions
diff --git a/generic/tclEncoding.c b/generic/tclEncoding.c
index a326856..0d03e2a 100644
--- a/generic/tclEncoding.c
+++ b/generic/tclEncoding.c
@@ -2413,7 +2413,7 @@ UtfToUtfProc(
 		/* A surrogate character is detected, handle especially */
 		Tcl_UniChar low = *chPtr;
 		size_t len = (src <= srcEnd-3) ? Tcl_UtfToUniChar(src, &low) : 0;
-		if (((low | 0x3FF) != 0xDFFF) || !(*chPtr & 0x800)) {
+		if (((low | 0x3FF) != 0xDFFF) || (*chPtr & 0x400)) {
 			*dst++ = (char) (((*chPtr >> 12) | 0xE0) & 0xEF);
 			*dst++ = (char) (((*chPtr >> 6) | 0x80) & 0xBF);
 			*dst++ = (char) ((*chPtr | 0x80) & 0xBF);
diff --git a/tests/encoding.test b/tests/encoding.test
index 9c77f3e..1eb6ec5 100644
--- a/tests/encoding.test
+++ b/tests/encoding.test
@@ -321,11 +321,11 @@ test encoding-15.3 {UtfToUtfProc null character input} teststringbytes {
     binary scan [teststringbytes $y] H* z
     set z
 } c080
-test encoding-15.4 {UtfToUtfProc emoji character input} {
+test encoding-15.4 {UtfToUtfProc emoji character input} -constraints knownBug -body {
     set x \xED\xA0\xBD\xED\xB8\x82
     set y [encoding convertfrom utf-8 \xED\xA0\xBD\xED\xB8\x82]
     list [string length $x] $y
-} "6 \U1F602"
+} -result "6 \U1F602"
 test encoding-15.5 {UtfToUtfProc emoji character input} {
     set x \xF0\x9F\x98\x82
     set y [encoding convertfrom utf-8 \xF0\x9F\x98\x82]
@@ -355,7 +355,43 @@ test encoding-15.9 {UtfToUtfProc emoji character output} {
     binary scan $y H* z
     list [string length $x] [string length $y] $z
 } {3 7 edb882eda0bd58}
-test encoding-15.10 {UtfToUtfProc emoji character output} {
+test encoding-15.10 {UtfToUtfProc high surrogate character output} {
+    set x \uDE02\xE9
+    set y [encoding convertto utf-8 \uDE02\xE9]
+    binary scan $y H* z
+    list [string length $x] [string length $y] $z
+} {2 5 edb882c3a9}
+test encoding-15.11 {UtfToUtfProc low surrogate character output} {
+    set x \uDA02\xE9
+    set y [encoding convertto utf-8 \uDA02\xE9]
+    binary scan $y H* z
+    list [string length $x] [string length $y] $z
+} {2 5 eda882c3a9}
+test encoding-15.12 {UtfToUtfProc high surrogate character output} {
+    set x \uDE02Y
+    set y [encoding convertto utf-8 \uDE02Y]
+    binary scan $y H* z
+    list [string length $x] [string length $y] $z
+} {2 4 edb88259}
+test encoding-15.13 {UtfToUtfProc low surrogate character output} {
+    set x \uDA02Y
+    set y [encoding convertto utf-8 \uDA02Y]
+    binary scan $y H* z
+    list [string length $x] [string length $y] $z
+} {2 4 eda88259}
+test encoding-15.14 {UtfToUtfProc high surrogate character output} {
+    set x \uDE02
+    set y [encoding convertto utf-8 \uDE02]
+    binary scan $y H* z
+    list [string length $x] [string length $y] $z
+} {1 3 edb882}
+test encoding-15.15 {UtfToUtfProc low surrogate character output} {
+    set x \uDA02
+    set y [encoding convertto utf-8 \uDA02]
+    binary scan $y H* z
+    list [string length $x] [string length $y] $z
+} {1 3 eda882}
+test encoding-15.16 {UtfToUtfProc emoji character output} {
     set x \U1F602
     set y [encoding convertto utf-8 \U1F602]
     binary scan $y H* z