diff --git a/src/org/ice1000/tt/psi/agda/parser.kt b/src/org/ice1000/tt/psi/agda/parser.kt
index 5e7c84f..85f3416 100644
--- a/src/org/ice1000/tt/psi/agda/parser.kt
+++ b/src/org/ice1000/tt/psi/agda/parser.kt
@@ -36,7 +36,8 @@ class AgdaTokenType(debugName: String) : IElementType(debugName, AgdaLanguage.IN
 		@JvmField val IDENTIFIERS = TokenSet.create(AgdaTypes.IDENTIFIER)
 
 		fun fromText(text: String, project: Project) = PsiFileFactory.getInstance(project).createFileFromText(AgdaLanguage.INSTANCE, text)?.firstChild
-		fun createSignature(text: String, project: Project) = fromText(text, project) as? AgdaSignature
+		fun createLayout(text: String, project: Project) = fromText(text, project) as? AgdaLayout
+		fun createSignature(text: String, project: Project) = createLayout(text, project)?.firstChild as? AgdaSignature
 		fun createExp(text: String, project: Project) = createSignature("f : $text", project)?.exp
 		fun createStr(text: String, project: Project) = createExp(text, project) as? AgdaString
 	}
diff --git a/src/org/ice1000/tt/psi/layout.kt b/src/org/ice1000/tt/psi/layout.kt
index f247392..2d7671a 100644
--- a/src/org/ice1000/tt/psi/layout.kt
+++ b/src/org/ice1000/tt/psi/layout.kt
@@ -113,7 +113,7 @@ class LayoutLexer(
 			when (state) {
 				WaitingForLayout -> {
 					if (token.isCode && token.column > indentStack.peek()) {
-						tokens.add(i, virtualToken(layoutStart, tokens[i - 1]))
+						tokens.add(i, virtualToken(layoutStart, tokens[(i - 1).coerceAtLeast(0)]))
 						i++
 						indentStack.push(token.column)
 						if (token.elementType !in layoutCreatingTokens) state = Normal