[parameter hints] treat absence of closing parenthesis as error

platform/platform-impl/src/com/intellij/codeInsight/hints/filtering/MethodMatcher.kt

@@ -56,19 +56,31 @@ object MatcherConstructor {
     val trimmedMatcher = matcher.trim()
     if (trimmedMatcher.isEmpty()) return null
 
-    val index = trimmedMatcher.indexOf('(')
-    if (index < 0) {
+    val openParenthIndex = trimmedMatcher.indexOf('(')
+    if (openParenthIndex < 0) {
       return Couple(trimmedMatcher, "")
     }
-    else if (index == 0) {
-      return Couple("", trimmedMatcher)
+    else if (openParenthIndex == 0) {
+      val paramsMatcher = getParamsMatcher(trimmedMatcher) ?: return null
+      return Couple("", paramsMatcher)
     }
 
-    val methodMatcher = trimmedMatcher.substring(0, index)
-    val paramsMatcher = trimmedMatcher.substring(index)
+    val methodMatcher = trimmedMatcher.substring(0, openParenthIndex)
+    val paramsMatcher = getParamsMatcher(trimmedMatcher) ?: return null
 
     return Couple(methodMatcher.trim(), paramsMatcher.trim())
   }
+  
+  private fun getParamsMatcher(matcher: String): String? {
+    val openBraceIndex = matcher.indexOf("(")
+    val closeBraceIndex = matcher.indexOf(")")
+
+    if (openBraceIndex >= 0 && closeBraceIndex > 0) {
+      return matcher.substring(openBraceIndex, closeBraceIndex + 1).trim()
+    }
+    
+    return null
+  }
 
   private fun createParametersMatcher(paramsMatcher: String): ParamMatcher? {
     if (paramsMatcher.length <= 2) return null

platform/platform-tests/testSrc/com/intellij/codeInsight/hints/filtering/PatternExtractionTest.kt

@@ -31,6 +31,16 @@ class PatternExtractionTest : TestCase() {
     assertThat(nameMatcher).isEqualTo(matcher.first)
     assertThat(paramsMatcher).isEqualTo(matcher.second)
   }
+  
+  fun String.assertError() {
+    val matcher = MatcherConstructor.extract(this)
+    assertThat(matcher).isNull()
+  }
+  
+  fun `test error when no closing brace`() {
+    val text = "Test.foo(paramName"
+    text.assertError()
+  }
 
   fun `test match all methods from package`() {
     val text = "java.lang.*"