Restarting completion when new suggestions may appear

idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/CompletionSession.kt

@@ -21,6 +21,7 @@ import com.intellij.codeInsight.completion.impl.CamelHumpMatcher
 import com.intellij.openapi.project.Project
 import com.intellij.openapi.vfs.VirtualFile
 import com.intellij.patterns.ElementPattern
+import com.intellij.patterns.PatternCondition
 import com.intellij.patterns.StandardPatterns
 import com.intellij.psi.PsiCompiledElement
 import com.intellij.psi.PsiElement
@@ -28,6 +29,7 @@ import com.intellij.psi.impl.source.tree.LeafPsiElement
 import com.intellij.psi.search.DelegatingGlobalSearchScope
 import com.intellij.psi.search.GlobalSearchScope
 import com.intellij.psi.util.PsiTreeUtil
+import com.intellij.util.ProcessingContext
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.idea.caches.resolve.ResolutionFacade
 import org.jetbrains.kotlin.idea.caches.resolve.getResolutionFacade
@@ -350,6 +352,15 @@ class BasicCompletionSession(configuration: CompletionSessionConfiguration,
     override fun doComplete() {
         assert(parameters.getCompletionType() == CompletionType.BASIC)
 
+        // if we are typing parameter name, restart completion each time we type an upper case letter because new suggestions will appear (previous words can be used as user prefix)
+        if (parameterNameAndTypeCompletion != null) {
+            val prefixPattern = StandardPatterns.string().with(object : PatternCondition<String>("Prefix ends with uppercase letter") {
+                override fun accepts(prefix: String, context: ProcessingContext?) = prefix.isNotEmpty() && prefix.last().isUpperCase()
+            })
+            (CompletionService.getCompletionService().getCurrentCompletion() as CompletionProgressIndicator)
+                    .addWatchedPrefix(parameters.getOffset(), prefixPattern)
+        }
+
         if (completionKind == CompletionKind.PARAMETER_NAME || completionKind == CompletionKind.ANNOTATION_TYPES_OR_PARAMETER_NAME) {
             collector.suppressItemSelectionByCharsOnTyping = true
         }