Introduce ResolvableType.forParameter() factory method

Prior to this commit, one could invoke
ResolvableType.forMethodParameter(MethodParameter.forParameter(parameter))
to create a ResolvableType for a Parameter; however, that's slightly
cumbersome.

To address that, this commit introduces ResolvableType.forParameter(),
analogous to existing convenience factory methods in ResolvableType.

Closes gh-36545

Author: sbrannen

spring-core/src/main/java/org/springframework/core/MethodParameter.java

@@ -822,6 +822,7 @@ else if (executable instanceof Constructor<?> constructor) {
 	 * @since 5.0
 	 */
 	public static MethodParameter forParameter(Parameter parameter) {
+		Assert.notNull(parameter, "Parameter must not be null");
 		return forExecutable(parameter.getDeclaringExecutable(), findParameterIndex(parameter));
 	}
 

spring-core/src/main/java/org/springframework/core/ResolvableType.java

@@ -22,6 +22,7 @@
 import java.lang.reflect.Field;
 import java.lang.reflect.GenericArrayType;
 import java.lang.reflect.Method;
+import java.lang.reflect.Parameter;
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
 import java.lang.reflect.TypeVariable;
@@ -1280,6 +1281,18 @@ public static ResolvableType forField(Field field, int nestingLevel, @Nullable C
 		return forType(null, new FieldTypeProvider(field), owner.asVariableResolver()).getNested(nestingLevel);
 	}
 
+	/**
+	 * Return a {@code ResolvableType} for the specified {@link Parameter}.
+	 * <p>This is a convenience factory method for scenarios where a {@code Parameter}
+	 * descriptor is already available.
+	 * @param parameter the source parameter
+	 * @return a {@code ResolvableType} for the specified parameter
+	 * @since 7.1
+	 */
+	public static ResolvableType forParameter(Parameter parameter) {
+		return forMethodParameter(MethodParameter.forParameter(parameter));
+	}
+
 	/**
 	 * Return a {@code ResolvableType} for the specified {@link Constructor} parameter.
 	 * @param constructor the source constructor (must not be {@code null})

spring-core/src/test/java/org/springframework/core/ResolvableTypeTests.java

@@ -25,6 +25,7 @@
 import java.lang.reflect.Field;
 import java.lang.reflect.GenericArrayType;
 import java.lang.reflect.Method;
+import java.lang.reflect.Parameter;
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
 import java.lang.reflect.TypeVariable;
@@ -207,6 +208,29 @@ void forFieldMustNotBeNull() {
 				.withMessage("Field must not be null");
 	}
 
+	@Test
+	void forParameterForMethod() throws Exception {
+		Method method = Methods.class.getMethod("charSequenceParameter", List.class);
+		Parameter parameter = method.getParameters()[0];
+		ResolvableType type = ResolvableType.forParameter(parameter);
+		assertThat(type.getType()).isEqualTo(method.getGenericParameterTypes()[0]);
+	}
+
+	@Test
+	void forParameterForConstructor() throws Exception {
+		Constructor<Constructors> constructor = Constructors.class.getConstructor(List.class);
+		Parameter parameter = constructor.getParameters()[0];
+		ResolvableType type = ResolvableType.forParameter(parameter);
+		assertThat(type.getType()).isEqualTo(constructor.getGenericParameterTypes()[0]);
+	}
+
+	@Test
+	void forParameterMustNotBeNull() {
+		assertThatIllegalArgumentException()
+				.isThrownBy(() -> ResolvableType.forParameter(null))
+				.withMessage("Parameter must not be null");
+	}
+
 	@Test
 	void forConstructorParameter() throws Exception {
 		Constructor<Constructors> constructor = Constructors.class.getConstructor(List.class);