diff --git a/idea/testData/multiModuleHighlighting/multiplatform/additionalMembersInPlatformInterface/common/common.kt b/idea/testData/multiModuleHighlighting/multiplatform/additionalMembersInPlatformInterface/common/common.kt
new file mode 100644
index 00000000000..5025978d657
--- /dev/null
+++ b/idea/testData/multiModuleHighlighting/multiplatform/additionalMembersInPlatformInterface/common/common.kt
@@ -0,0 +1,5 @@
+// KT-23745
+expect interface A
+expect interface B
+
+interface Both : A, B
\ No newline at end of file
diff --git a/idea/testData/multiModuleHighlighting/multiplatform/additionalMembersInPlatformInterface/js/js.kt b/idea/testData/multiModuleHighlighting/multiplatform/additionalMembersInPlatformInterface/js/js.kt
new file mode 100644
index 00000000000..9f0a157a71a
--- /dev/null
+++ b/idea/testData/multiModuleHighlighting/multiplatform/additionalMembersInPlatformInterface/js/js.kt
@@ -0,0 +1,10 @@
+actual interface A
+actual interface B {
+    fun z()
+    fun x()
+}
+
+<error descr="[ABSTRACT_MEMBER_NOT_IMPLEMENTED] Class 'Impl' is not abstract and does not implement abstract member public abstract fun x(): Unit defined in Both">class Impl</error> : Both {
+    override fun z() {
+    }
+}
\ No newline at end of file
diff --git a/idea/testData/multiModuleHighlighting/multiplatform/platformTypeAliasInterchangebleWithAliasedClass/a_common/Decimal.kt b/idea/testData/multiModuleHighlighting/multiplatform/platformTypeAliasInterchangebleWithAliasedClass/a_common/Decimal.kt
new file mode 100644
index 00000000000..91295e47137
--- /dev/null
+++ b/idea/testData/multiModuleHighlighting/multiplatform/platformTypeAliasInterchangebleWithAliasedClass/a_common/Decimal.kt
@@ -0,0 +1,4 @@
+// KT-23124
+package com.example
+
+expect class Decimal
\ No newline at end of file
diff --git a/idea/testData/multiModuleHighlighting/multiplatform/platformTypeAliasInterchangebleWithAliasedClass/a_common/Foo.kt b/idea/testData/multiModuleHighlighting/multiplatform/platformTypeAliasInterchangebleWithAliasedClass/a_common/Foo.kt
new file mode 100644
index 00000000000..a0338848f3d
--- /dev/null
+++ b/idea/testData/multiModuleHighlighting/multiplatform/platformTypeAliasInterchangebleWithAliasedClass/a_common/Foo.kt
@@ -0,0 +1,7 @@
+package com.example.bar
+
+import com.example.Decimal
+
+class Foo(
+    val bar: Decimal
+)
\ No newline at end of file
diff --git a/idea/testData/multiModuleHighlighting/multiplatform/platformTypeAliasInterchangebleWithAliasedClass/a_js/DecimalJs.kt b/idea/testData/multiModuleHighlighting/multiplatform/platformTypeAliasInterchangebleWithAliasedClass/a_js/DecimalJs.kt
new file mode 100644
index 00000000000..10c4d19576d
--- /dev/null
+++ b/idea/testData/multiModuleHighlighting/multiplatform/platformTypeAliasInterchangebleWithAliasedClass/a_js/DecimalJs.kt
@@ -0,0 +1,3 @@
+package com.example
+
+actual typealias Decimal = Double
\ No newline at end of file
diff --git a/idea/testData/multiModuleHighlighting/multiplatform/platformTypeAliasInterchangebleWithAliasedClass/a_js/ExampleJs.kt b/idea/testData/multiModuleHighlighting/multiplatform/platformTypeAliasInterchangebleWithAliasedClass/a_js/ExampleJs.kt
new file mode 100644
index 00000000000..4fbf32e4064
--- /dev/null
+++ b/idea/testData/multiModuleHighlighting/multiplatform/platformTypeAliasInterchangebleWithAliasedClass/a_js/ExampleJs.kt
@@ -0,0 +1,5 @@
+package com.example
+
+import com.example.bar.Foo
+
+val a = Foo(0.toDouble())
\ No newline at end of file
diff --git a/idea/testData/multiModuleHighlighting/multiplatform/platformTypeAliasInterchangebleWithAliasedClass/a_jvm_dep(fulljdk)/DecimalJvm.kt b/idea/testData/multiModuleHighlighting/multiplatform/platformTypeAliasInterchangebleWithAliasedClass/a_jvm_dep(fulljdk)/DecimalJvm.kt
new file mode 100644
index 00000000000..af0149627c1
--- /dev/null
+++ b/idea/testData/multiModuleHighlighting/multiplatform/platformTypeAliasInterchangebleWithAliasedClass/a_jvm_dep(fulljdk)/DecimalJvm.kt
@@ -0,0 +1,5 @@
+package com.example
+
+import java.math.BigDecimal
+
+actual typealias Decimal = BigDecimal
\ No newline at end of file
diff --git a/idea/testData/multiModuleHighlighting/multiplatform/platformTypeAliasInterchangebleWithAliasedClass/a_jvm_dep(fulljdk)/ExampleJvm.kt b/idea/testData/multiModuleHighlighting/multiplatform/platformTypeAliasInterchangebleWithAliasedClass/a_jvm_dep(fulljdk)/ExampleJvm.kt
new file mode 100644
index 00000000000..7c042584c93
--- /dev/null
+++ b/idea/testData/multiModuleHighlighting/multiplatform/platformTypeAliasInterchangebleWithAliasedClass/a_jvm_dep(fulljdk)/ExampleJvm.kt
@@ -0,0 +1,6 @@
+package com.example
+
+import com.example.bar.Foo
+import java.math.BigDecimal
+
+val a = Foo(BigDecimal(1))
\ No newline at end of file
diff --git a/idea/testData/multiModuleHighlighting/multiplatform/typeAliasedParameter/common/common.kt b/idea/testData/multiModuleHighlighting/multiplatform/typeAliasedParameter/common/common.kt
new file mode 100644
index 00000000000..b22e64dab6a
--- /dev/null
+++ b/idea/testData/multiModuleHighlighting/multiplatform/typeAliasedParameter/common/common.kt
@@ -0,0 +1,10 @@
+// KT-23760
+package foo
+
+expect interface Upper
+
+expect interface BaseI {
+    fun f(p: Upper)
+}
+
+interface I : BaseI
\ No newline at end of file
diff --git a/idea/testData/multiModuleHighlighting/multiplatform/typeAliasedParameter/jvm/jvm.kt b/idea/testData/multiModuleHighlighting/multiplatform/typeAliasedParameter/jvm/jvm.kt
new file mode 100644
index 00000000000..0c8b606294a
--- /dev/null
+++ b/idea/testData/multiModuleHighlighting/multiplatform/typeAliasedParameter/jvm/jvm.kt
@@ -0,0 +1,13 @@
+package foo
+
+interface X
+actual typealias Upper = X
+
+actual interface BaseI {
+    actual fun f(p: Upper)
+}
+
+internal class Impl : I {
+    override fun f(p: Upper) {
+    }
+}
\ No newline at end of file
diff --git a/idea/testData/multiModuleHighlighting/multiplatform/useAppendable/a_common_dep(stdlib)/common.kt b/idea/testData/multiModuleHighlighting/multiplatform/useAppendable/a_common_dep(stdlib)/common.kt
new file mode 100644
index 00000000000..3cb554cbbec
--- /dev/null
+++ b/idea/testData/multiModuleHighlighting/multiplatform/useAppendable/a_common_dep(stdlib)/common.kt
@@ -0,0 +1,4 @@
+// KT-20824
+package foo
+
+fun <O : Appendable> O.appendMe(): O = this // kotlin.text.Appendable
diff --git a/idea/testData/multiModuleHighlighting/multiplatform/useAppendable/a_jvm_dep(stdlib)_dep(fulljdk)/jvm.kt b/idea/testData/multiModuleHighlighting/multiplatform/useAppendable/a_jvm_dep(stdlib)_dep(fulljdk)/jvm.kt
new file mode 100644
index 00000000000..1cbd6b49619
--- /dev/null
+++ b/idea/testData/multiModuleHighlighting/multiplatform/useAppendable/a_jvm_dep(stdlib)_dep(fulljdk)/jvm.kt
@@ -0,0 +1,7 @@
+package foo
+
+fun tryIt() {
+    buildString {  // kotlin.text.StringBuilder = java.lang.StringBuilder
+        appendMe()
+    }
+}
\ No newline at end of file
diff --git a/idea/testData/multiModuleHighlighting/multiplatform/usePlatformSpecificMember/common/common.kt b/idea/testData/multiModuleHighlighting/multiplatform/usePlatformSpecificMember/common/common.kt
new file mode 100644
index 00000000000..b5aadb8ceec
--- /dev/null
+++ b/idea/testData/multiModuleHighlighting/multiplatform/usePlatformSpecificMember/common/common.kt
@@ -0,0 +1,7 @@
+// KT-20605
+package foo
+
+expect class C {
+}
+
+fun getC(): C? = null
\ No newline at end of file
diff --git a/idea/testData/multiModuleHighlighting/multiplatform/usePlatformSpecificMember/jvm/jvm.kt b/idea/testData/multiModuleHighlighting/multiplatform/usePlatformSpecificMember/jvm/jvm.kt
new file mode 100644
index 00000000000..61d844374a1
--- /dev/null
+++ b/idea/testData/multiModuleHighlighting/multiplatform/usePlatformSpecificMember/jvm/jvm.kt
@@ -0,0 +1,15 @@
+package foo
+
+actual class C {
+    fun zzz() {
+    }
+}
+
+fun works() {
+    C().zzz()
+}
+
+fun doesnNot() {
+    getC()?.zzz()
+    getC()?.zzz()
+}
\ No newline at end of file
diff --git a/idea/tests/org/jetbrains/kotlin/idea/caches/resolve/MultiModuleHighlightingTestGenerated.java b/idea/tests/org/jetbrains/kotlin/idea/caches/resolve/MultiModuleHighlightingTestGenerated.java
index 376f0f7078f..a8bf51984e6 100644
--- a/idea/tests/org/jetbrains/kotlin/idea/caches/resolve/MultiModuleHighlightingTestGenerated.java
+++ b/idea/tests/org/jetbrains/kotlin/idea/caches/resolve/MultiModuleHighlightingTestGenerated.java
@@ -25,6 +25,11 @@ public class MultiModuleHighlightingTestGenerated extends AbstractMultiModuleHig
         KotlinTestUtils.runTest(this::doTest, TargetBackend.ANY, testDataFilePath);
     }
 
+    @TestMetadata("additionalMembersInPlatformInterface")
+    public void testAdditionalMembersInPlatformInterface() throws Exception {
+        runTest("idea/testData/multiModuleHighlighting/multiplatform/additionalMembersInPlatformInterface/");
+    }
+
     public void testAllFilesPresentInMultiplatform() throws Exception {
         KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/multiModuleHighlighting/multiplatform"), Pattern.compile("^([^\\.]+)$"), TargetBackend.ANY, false);
     }
@@ -84,6 +89,11 @@ public class MultiModuleHighlightingTestGenerated extends AbstractMultiModuleHig
         runTest("idea/testData/multiModuleHighlighting/multiplatform/nestedClassWithoutImpl/");
     }
 
+    @TestMetadata("platformTypeAliasInterchangebleWithAliasedClass")
+    public void testPlatformTypeAliasInterchangebleWithAliasedClass() throws Exception {
+        runTest("idea/testData/multiModuleHighlighting/multiplatform/platformTypeAliasInterchangebleWithAliasedClass/");
+    }
+
     @TestMetadata("suppressHeaderWithoutImpl")
     public void testSuppressHeaderWithoutImpl() throws Exception {
         runTest("idea/testData/multiModuleHighlighting/multiplatform/suppressHeaderWithoutImpl/");
@@ -104,11 +114,26 @@ public class MultiModuleHighlightingTestGenerated extends AbstractMultiModuleHig
         runTest("idea/testData/multiModuleHighlighting/multiplatform/triangleWithDependency/");
     }
 
+    @TestMetadata("typeAliasedParameter")
+    public void testTypeAliasedParameter() throws Exception {
+        runTest("idea/testData/multiModuleHighlighting/multiplatform/typeAliasedParameter/");
+    }
+
+    @TestMetadata("useAppendable")
+    public void testUseAppendable() throws Exception {
+        runTest("idea/testData/multiModuleHighlighting/multiplatform/useAppendable/");
+    }
+
     @TestMetadata("useCorrectBuiltInsForCommonModule")
     public void testUseCorrectBuiltInsForCommonModule() throws Exception {
         runTest("idea/testData/multiModuleHighlighting/multiplatform/useCorrectBuiltInsForCommonModule/");
     }
 
+    @TestMetadata("usePlatformSpecificMember")
+    public void testUsePlatformSpecificMember() throws Exception {
+        runTest("idea/testData/multiModuleHighlighting/multiplatform/usePlatformSpecificMember/");
+    }
+
     @TestMetadata("withOverrides")
     public void testWithOverrides() throws Exception {
         runTest("idea/testData/multiModuleHighlighting/multiplatform/withOverrides/");