diff --git a/src/main/java/org/codehaus/groovy/transform/stc/StaticTypeCheckingSupport.java b/src/main/java/org/codehaus/groovy/transform/stc/StaticTypeCheckingSupport.java
index c5d5e0755b1..ea94d53145c 100644
--- a/src/main/java/org/codehaus/groovy/transform/stc/StaticTypeCheckingSupport.java
+++ b/src/main/java/org/codehaus/groovy/transform/stc/StaticTypeCheckingSupport.java
@@ -175,8 +175,8 @@ public abstract class StaticTypeCheckingSupport {
             Short_TYPE,   1,
             int_TYPE,     2,
             Integer_TYPE, 2,
-            Long_TYPE,    3,
             long_TYPE,    3,
+            Long_TYPE,    3,
             float_TYPE,   4,
             Float_TYPE,   4,
             double_TYPE,  5,
@@ -453,8 +453,11 @@ public static boolean isAssignableTo(ClassNode type, ClassNode toBeAssignedTo) {
         if (type == toBeAssignedTo || type == UNKNOWN_PARAMETER_TYPE) return true;
         if (isPrimitiveType(type)) type = getWrapper(type);
         if (isPrimitiveType(toBeAssignedTo)) toBeAssignedTo = getWrapper(toBeAssignedTo);
-        if (NUMBER_TYPES.containsKey(type.redirect()) && NUMBER_TYPES.containsKey(toBeAssignedTo.redirect())) {
-            return NUMBER_TYPES.get(type.redirect()) <= NUMBER_TYPES.get(toBeAssignedTo.redirect());
+        Integer source= NUMBER_TYPES.get(type), target= NUMBER_TYPES.get(toBeAssignedTo);
+        if (source != null && target != null) { return (source.compareTo(target) <= 0); }
+        // GROOVY-8325, GROOVY-8488: float or double can be assigned a BigDecimal literal
+        if (BigDecimal_TYPE.equals(type) && (Double_TYPE.equals(toBeAssignedTo) || Float_TYPE.equals(toBeAssignedTo))) {
+            return true;
         }
         if (type.isArray() && toBeAssignedTo.isArray()) {
             ClassNode sourceComponent = type.getComponentType(), targetComponent = toBeAssignedTo.getComponentType();
diff --git a/src/test/groovy/transform/stc/MethodCallsSTCTest.groovy b/src/test/groovy/transform/stc/MethodCallsSTCTest.groovy
index 8887b4d2062..607c6e97586 100644
--- a/src/test/groovy/transform/stc/MethodCallsSTCTest.groovy
+++ b/src/test/groovy/transform/stc/MethodCallsSTCTest.groovy
@@ -944,6 +944,42 @@ class MethodCallsSTCTest extends StaticTypeCheckingTestCase {
         }
     }
 
+    // GROOVY-8488
+    void testBigDecimalLiteralArgument() {
+        assertScript '''
+            def m1(double d) { Double.valueOf(d) }
+            def m2(float f) { Float.valueOf(f) }
+            assert m1(1.0) == 1.0d
+            assert m2(1.0) == 1.0f
+        '''
+
+        shouldFailWithMessages '''
+            class C {
+                def m1(long l) { Long.valueOf(l) }
+                def m2(int i) { new Integer(i) }
+                void test() {
+                    m1(1.0)
+                    m2(1.0)
+                }
+            }
+        ''',
+        'Cannot find matching method C#m1(java.math.BigDecimal)',
+        'Cannot find matching method C#m2(java.math.BigDecimal)'
+
+        shouldFailWithMessages '''
+            class C {
+                def m1(long l) { Long.valueOf(l) }
+                def m2(int i) { new Integer(i) }
+                void test() {
+                    m1(1g)
+                    m2(1g)
+                }
+            }
+        ''',
+        'Cannot find matching method C#m1(java.math.BigInteger)',
+        'Cannot find matching method C#m2(java.math.BigInteger)'
+    }
+
     void testBoxingShouldCostMore() {
         assertScript '''
             int foo(int x) { 1 }