Prevent panics when building argument lists for variadic functions

internal/compiler/resolve.go

@@ -334,9 +334,12 @@ func (comp *Compiler) resolveCatalogRefs(qc *QueryCatalog, rvs []*ast.RangeVar,
 
 				var paramName string
 				var paramType *ast.TypeName
+
 				if argName == "" {
-					paramName = fun.Args[i].Name
-					paramType = fun.Args[i].Type
+					if i < len(fun.Args) {
+						paramName = fun.Args[i].Name
+						paramType = fun.Args[i].Type
+					}
 				} else {
 					paramName = argName
 					for _, arg := range fun.Args {
@@ -351,6 +354,9 @@ func (comp *Compiler) resolveCatalogRefs(qc *QueryCatalog, rvs []*ast.RangeVar,
 				if paramName == "" {
 					paramName = funcName
 				}
+				if paramType == nil {
+					paramType = &ast.TypeName{Name: ""}
+				}
 
 				defaultP := named.NewInferredParam(paramName, true)
 				p, isNamed := params.FetchMerge(ref.ref.Number, defaultP)

internal/endtoend/testdata/func_variadic/postgresql/stdlib/query.sql

@@ -0,0 +1,12 @@
+CREATE TABLE test (
+    id integer,
+    j jsonb NOT NULL
+    );
+
+-- name: UpdateJ :exec
+UPDATE
+    test
+SET
+    j = jsonb_build_object($1, $2, $3, $4)
+WHERE
+    id = $5;

internal/endtoend/testdata/func_variadic/postgresql/stdlib/sqlc.json

@@ -0,0 +1,12 @@
+{
+  "version": "1",
+  "packages": [
+    {
+      "path": "go",
+      "engine": "postgresql",
+      "name": "querytest",
+      "schema": "query.sql",
+      "queries": "query.sql"
+    }
+  ]
+}

internal/sql/catalog/func.go

@@ -9,7 +9,7 @@ import (
 
 // Function describes a database function
 //
-// A database function is a method written to performs specific operation on data within the database.
+// A database function is a method written to perform a specific operation on data within the database.
 type Function struct {
 	Name               string
 	Args               []*Argument