GROOVY-10254

Author: eric-milles

base-test/org.eclipse.jdt.groovy.core.tests.compiler/src/org/eclipse/jdt/groovy/core/tests/xform/TypeCheckedTests.java

@@ -3635,4 +3635,20 @@ public void testTypeChecked10239a() {
 
         runConformTest(sources, "2");
     }
+
+    @Test
+    public void testTypeChecked10254() {
+        //@formatter:off
+        String[] sources = {
+            "Main.groovy",
+            "@groovy.transform.TypeChecked\n" +
+            "java.util.function.Supplier<Integer> test() {\n" +
+            "  { -> 42 }\n" + // should coerce without "as Supplier<Integer>"
+            "}\n" +
+            "print(test().get())\n",
+        };
+        //@formatter:on
+
+        runConformTest(sources, "42");
+    }
 }

base/org.codehaus.groovy25/src/org/codehaus/groovy/transform/stc/StaticTypeCheckingSupport.java

@@ -802,6 +802,11 @@ public static boolean checkCompatibleAssignmentTypes(ClassNode left, ClassNode r
         if (leftRedirect.equals(GROOVY_OBJECT_TYPE) && isBeingCompiled(right)) {
             return true;
         }
+        // GRECLIPSE add -- GROOVY-10254
+        if (right.isDerivedFrom(CLOSURE_TYPE) && isSAMType(left)) {
+            return true;
+        }
+        // GRECLIPSE end
 
         if (left.isGenericsPlaceHolder()) {
             // GROOVY-7307

base/org.codehaus.groovy30/src/org/codehaus/groovy/transform/stc/StaticTypeCheckingSupport.java

@@ -753,6 +753,11 @@ public static boolean checkCompatibleAssignmentTypes(final ClassNode left, final
         if (GROOVY_OBJECT_TYPE.equals(leftRedirect) && isBeingCompiled(right)) {
             return true;
         }
+        // GRECLIPSE add -- GROOVY-10254
+        if (right.isDerivedFrom(CLOSURE_TYPE) && isSAMType(left)) {
+            return true;
+        }
+        // GRECLIPSE end
 
         if (left.isGenericsPlaceHolder()) {
             // GROOVY-7307

base/org.codehaus.groovy40/src/org/codehaus/groovy/transform/stc/StaticTypeCheckingSupport.java

@@ -745,6 +745,10 @@ public static boolean checkCompatibleAssignmentTypes(final ClassNode left, final
         if (isGroovyObjectType(leftRedirect) && isBeingCompiled(right)) {
             return true;
         }
+        // GRECLIPSE add -- GROOVY-10254
+        if (right.isDerivedFrom(CLOSURE_TYPE) && isSAMType(left)) {
+            return true;
+        }
 
         /* GRECLIPSE edit -- GROOVY-7307, GROOVY-7316, GROOVY-10256
         return right.isGenericsPlaceHolder();