Find useless coalesce, concat, or concat_ws calls with only one argument

WITH objects AS (
    -- 1. Views and Materialized Views
    SELECT 
        n.nspname AS schema_name, 
        c.relname AS object_name, 
        CASE WHEN c.relkind='v' THEN 'VIEW' WHEN c.relkind='m' THEN 'MATERIALIZED VIEW' END AS object_type,
        pg_get_viewdef(c.oid, true) AS object_definition
    FROM pg_namespace AS n 
    INNER JOIN pg_authid AS a ON n.nspowner=a.oid
    INNER JOIN pg_class AS c ON n.oid=c.relnamespace
    WHERE (n.nspname='public' OR a.rolname<>'postgres')
    AND c.relkind IN ('v','m')

    UNION ALL

    -- 2. Functions and Procedures
    SELECT 
        pg_namespace.nspname AS schema_name, 
        pg_proc.proname || '(' || pg_get_function_identity_arguments(pg_proc.oid) || ')' AS object_name,
        CASE WHEN pg_proc.prokind='f' THEN 'FUNCTION'
             WHEN pg_proc.prokind='p' THEN 'PROCEDURE'
             WHEN pg_proc.prokind='w' THEN 'WINDOW FUNCTION' END AS object_type,
        pg_get_functiondef(pg_proc.oid) AS object_definition
    FROM pg_catalog.pg_proc
    JOIN pg_catalog.pg_namespace ON pg_proc.pronamespace = pg_namespace.oid
    WHERE pg_proc.prokind <> 'a'
      AND pg_proc.proname NOT IN ('f_assume_you_must_use_files', 'f_check_format_comma_separated_list', 'f_check_password', 'f_default_value_with_no_match') 
      AND pg_namespace.nspname NOT IN (SELECT schema_name FROM INFORMATION_SCHEMA.schemata WHERE schema_name<>'public' AND schema_owner='postgres' AND schema_name IS NOT NULL) 
      AND NOT EXISTS (SELECT 1 FROM pg_catalog.pg_depend d WHERE EXISTS (SELECT 1 FROM pg_catalog.pg_extension e WHERE d.refobjid=e.oid) AND d.objid=pg_proc.oid)
),
cleaned_objects AS (
    SELECT 
        schema_name,
        object_name,
        object_type,
        object_definition,
        -- Clean the definition by removing strings and quoted identifiers.
        -- This is crucial so that commas inside strings (e.g., "Lastname, Firstname") 
        -- are not misinterpreted as argument separators.
        -- 1. Replace 'text' -> $STR$
        -- 2. Replace "text" -> $ID$
        regexp_replace(
            regexp_replace(object_definition, '''([^'']|'''')*''', '$STR$', 'g'), 
            '"([^"]|"")*"', '$ID$', 'g'
        ) AS clean_def
    FROM objects
)
SELECT 
    schema_name, 
    object_name, 
    object_type, 
    regexp_replace(object_definition,'[\r\n]','<br>','g') AS object_def
FROM cleaned_objects
WHERE 
    -- Regular expression to find single-argument calls:
    -- \y(coalesce|concat|concat_ws)      : Function name (with word boundary)
    -- \s*\(                              : Opening parenthesis
    -- (?:                                : Content group
    --   [^(),]                           : 1. Any character that is not a comma or parenthesis
    --   |                                : OR
    --   \((?:[^()]|\([^()]*\))*\)        : 2. Nested parentheses (handles logic like string_agg(a,b) inside the argument)
    -- )*                                 : Repeat content
    -- \)                                 : Closing parenthesis
    -- If this pattern matches, it means there are no top-level commas (outside nested parentheses), implying only one argument.
    clean_def ~* '\y(coalesce|concat|concat_ws)\s*\((?:[^(),]|\((?:[^()]|\([^()]*\))*\))*\)'
ORDER BY schema_name, object_type, object_name;