3 files changed, 43 insertions, 0 deletions
diff --git a/tests/iii/operator-result-errors/case.json b/tests/iii/operator-result-errors/case.json
new file mode 100644
index 0000000..67abec2
--- /dev/null
+++ b/tests/iii/operator-result-errors/case.json
@@ -0,0 +1,20 @@
+{
+  "errors": [
+    {
+      "reason": "Cannot implicitly convert STRING to BOOLEAN",
+      "line": 8
+    },
+    {
+      "reason": "Cannot implicitly convert STRING to BOOLEAN",
+      "line": 12
+    },
+    {
+      "reason": "Cannot implicitly convert STRING to BOOLEAN",
+      "line": 17
+    },
+    {
+      "reason": "CASE comparison must return BOOLEAN",
+      "line": 19
+    }
+  ]
+}
diff --git a/tests/iii/operator-result-errors/notes.md b/tests/iii/operator-result-errors/notes.md
new file mode 100644
index 0000000..bb407a2
--- /dev/null
+++ b/tests/iii/operator-result-errors/notes.md
@@ -0,0 +1,3 @@
+# operator-result-errors
+
+The equality operator returns STRING. Reject that result as an IF condition, BOOLEAN return value, BOOLEAN argument and CASE comparison.
diff --git a/tests/iii/operator-result-errors/program.cps b/tests/iii/operator-result-errors/program.cps
new file mode 100644
index 0000000..8cf9ede
--- /dev/null
+++ b/tests/iii/operator-result-errors/program.cps
@@ -0,0 +1,20 @@
+CLASS Box
+Value : INTEGER
+OVERLOAD FUNCTION OPERATOR=(rhs : Box) RETURNS STRING
+RETURN "text"
+ENDFUNCTION
+ENDCLASS
+DECLARE item : Box
+IF item = item THEN
+OUTPUT "wrong"
+ENDIF
+FUNCTION Bad(value : Box) RETURNS BOOLEAN
+RETURN value = value
+ENDFUNCTION
+FUNCTION NeedBool(flag : BOOLEAN) RETURNS INTEGER
+RETURN 0
+ENDFUNCTION
+OUTPUT NeedBool(item = item)
+CASE OF item
+item : OUTPUT "wrong"
+ENDCASE