improved type inference in plugin

lynglib/src/commonTest/kotlin/MiniAstTest.kt

@@ -458,4 +458,19 @@ class MiniAstTest {
         val className = DocLookupUtils.simpleClassNameOf(type)
         assertEquals("List", className)
     }
+
+    @Test
+    fun miniAst_captures_fun_with_type_and_default() = runTest {
+        val code = """
+            fun foo(a: Int, b: String = "ok"): Bool { true }
+        """.trimIndent()
+        val (_, sink) = compileWithMini(code)
+        val mini = sink.build()
+        assertNotNull(mini)
+        val fn = mini.declarations.filterIsInstance<MiniFunDecl>().firstOrNull { it.name == "foo" }
+        assertNotNull(fn)
+        assertEquals(2, fn.params.size)
+        assertEquals("a", fn.params[0].name)
+        assertEquals("b", fn.params[1].name)
+    }
 }

lynglib/src/commonTest/kotlin/net/sergeych/lyng/miniast/ParamTypeInferenceTest.kt

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2026 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package net.sergeych.lyng.miniast
+
+import kotlinx.coroutines.test.runTest
+import net.sergeych.lyng.Compiler
+import net.sergeych.lyng.binding.Binder
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class ParamTypeInferenceTest {
+
+    @Test
+    fun testParameterTypeInference() = runTest {
+        val code = """
+            class A {
+                fun foo(p: String) {
+                    p.
+                }
+            }
+            
+            fun bar(q: Int) {
+                q.
+            }
+        """.trimIndent()
+
+        val sink = MiniAstBuilder()
+        Compiler.compileWithMini(code.trimIndent(), sink)
+        val mini = sink.build()!!
+        val binding = Binder.bind(code, mini)
+
+        val dotPosQ = code.indexOf("q.") + 1
+        val receiverClassQ = DocLookupUtils.guessReceiverClassViaMini(mini, code, dotPosQ, listOf("lyng.stdlib"), binding)
+        assertEquals("Int", receiverClassQ, "Should infer type of parameter q in top-level function")
+
+        val dotPosP = code.indexOf("p.") + 1
+        val receiverClassP = DocLookupUtils.guessReceiverClassViaMini(mini, code, dotPosP, listOf("lyng.stdlib"), binding)
+        assertEquals("String", receiverClassP, "Should infer type of parameter p in member function")
+    }
+}