Fix expression conversion

src/main/java/ch/njol/skript/lang/SkriptParser.java

@@ -371,8 +371,13 @@ private <T> Expression<? extends T> parseSingleExpr(boolean allowUnparsedLiteral
 					for (Class<? extends T> type : types) {
 						// Check return type against everything that expression accepts
 						if (parsedExpression.canReturn(type)) {
-							log.printLog();
-							return (Expression<? extends T>) parsedExpression;
+							Expression<? extends T> convertedExpression = parsedExpression.getConvertedExpression(type);
+							if (convertedExpression != null) {
+								log.printLog();
+								return convertedExpression;
+							}
+							log.printError(parsedExpression.toString(null, false) + " " + Language.get("is") + " " + notOfType(type), ErrorQuality.NOT_AN_EXPRESSION);
+							return null;
 						}
 					}
 
@@ -556,8 +561,13 @@ private Expression<?> parseSingleExpr(boolean allowUnparsedLiteral, @Nullable Lo
 								return null;
 							}
 
-							log.printLog();
-							return parsedExpression;
+							Expression<?> convertedExpression = parsedExpression.getConvertedExpression(type);
+							if (convertedExpression != null) {
+								log.printLog();
+								return convertedExpression;
+							}
+							log.printError(parsedExpression.toString(null, false) + " " + Language.get("is") + " " + notOfType(type), ErrorQuality.NOT_AN_EXPRESSION);
+							return null;
 						}
 					}
 

src/test/skript/tests/regressions/7164-expressions sometimes dont convert

@@ -0,0 +1,13 @@
+test "expressions sometimes dont convert":
+	assert formatted ({_foo} + {_bar}) is not set with "formatting nothing shouldn't throw an error"
+
+	set {_foo} to "test"
+	assert formatted ({_foo} + {_bar}) is not set with "formatting string + none shouldn't throw an error"
+
+	set {_foo} to 1
+	set {_bar} to 2
+	assert formatted ({_foo} + {_bar}) is not set with "formatting number + number shouldn't throw an error"
+
+	set {_foo} to "foo"
+	set {_bar} to "bar"
+	assert formatted ({_foo} + {_bar}) is "foobar" with "formatting strings doesn't work"