From 47a77d771a0a4c1b9eb037ed6cc861e67000e8dd Mon Sep 17 00:00:00 2001
From: "elias.oelschner" <elioelsch@oelschner.eu>
Date: Fri, 16 Jan 2026 13:58:18 +0100
Subject: [PATCH] Fix function call parsing and add test

---
 src/prometheus/parser.lua | 14 ++++++++++++++
 tests/ambiguous-call.lua  |  8 ++++++++
 2 files changed, 22 insertions(+)
 create mode 100644 tests/ambiguous-call.lua

diff --git a/src/prometheus/parser.lua b/src/prometheus/parser.lua
index 1594b2f..10cdd5f 100644
--- a/src/prometheus/parser.lua
+++ b/src/prometheus/parser.lua
@@ -38,6 +38,13 @@ local ASSIGNMENT_NO_WARN_LOOKUP = lookupify{
 	AstKind.VarargExpression
 };
 
+local CALLABLE_PREFIX_EXPRESSION_LOOKUP = lookupify{
+	AstKind.VariableExpression,
+	AstKind.IndexExpression,
+	AstKind.FunctionCallExpression,
+	AstKind.PassSelfFunctionCallExpression
+};
+
 local function generateError(self, message)
 	local token;
 	if(self.index > self.length) then
@@ -782,6 +789,10 @@ end
 
 function Parser:expressionFunctionCall(scope, base)
 	base = base or self:expressionIndex(scope);
+
+	if(not (base and (CALLABLE_PREFIX_EXPRESSION_LOOKUP[base.kind] or base.isParenthesizedExpression))) then
+		return base;
+	end
 	
 	-- Normal Function Call
 	local args = {};
@@ -887,6 +898,9 @@ function Parser:expressionLiteral(scope)
 	if(consume(self, TokenKind.Symbol, "(")) then
 		local expr = self:expression(scope);
 		expect(self, TokenKind.Symbol, ")");
+		if expr then
+			expr.isParenthesizedExpression = true;
+		end
 		return expr;
 	end
 	
diff --git a/tests/ambiguous-call.lua b/tests/ambiguous-call.lua
new file mode 100644
index 0000000..38a08b2
--- /dev/null
+++ b/tests/ambiguous-call.lua
@@ -0,0 +1,8 @@
+-- Reproduction for issue #203 where the parser misreads the following
+-- as arguments to the previous literal assignment.
+local counter = 1
+
+(function()
+	counter = counter + 1
+	print("counter:", counter)
+end)();