ADDITIONAL SYSTEM INFORMATION :
Java: openjdk 21.0.1 2023-10-17 LTS OpenJDK Runtime Environment Temurin-21.0.1+12 (build 21.0.1+12-LTS) OpenJDK 64-Bit Server VM Temurin-21.0.1+12 (build 21.0.1+12-LTS, mixed mode, sharing)

OS: Windows 11 on x86-64

A DESCRIPTION OF THE PROBLEM :
If a compact constructor is added to a record, that record's reflective Constructor object loses the generic type info on its Parameter objects.

See also: https://github.com/adoptium/adoptium-support/issues/1025

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the attached JUnit5 test case.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
All tests pass.
ACTUAL -
The "compact" test fails. The other tests pass.

---------- BEGIN SOURCE ----------
import java.lang.reflect.Type;
import java.util.List;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.assertEquals;

class RecordParameterTest {
public static List<String> fieldWithExpectedType;
public static Type expected;

@BeforeAll
static void determineExpectedType() throws NoSuchFieldException {
expected = RecordParameterTest.class.getField("fieldWithExpectedType").getGenericType();
}

record ImplicitConstructor(List<String> arg){}

record CompactConstructor(List<String> arg) {
CompactConstructor { }
}

record CanonicalConstructor(List<String> arg) {
CanonicalConstructor(List<String> arg) {
this.arg = arg;
}
}

@Test
void implicit() {
assertEquals(expected, firstConstructorParameterType(ImplicitConstructor.class));
}

@Test
void compact() {
assertEquals(expected, firstConstructorParameterType(CompactConstructor.class));
}

@Test
void canonical() {
assertEquals(expected, firstConstructorParameterType(CanonicalConstructor.class));
}

static Type firstConstructorParameterType(Class<?> c) {
return c.getDeclaredConstructors()[0].getParameters()[0].getParameterizedType();
}
}
---------- END SOURCE ----------

FREQUENCY : always