From 5dc1e4c991efae2e0dd96b59bc57b2cd81a8c5fb Mon Sep 17 00:00:00 2001
From: Eugen Wissner <belka@caraus.de>
Date: Fri, 24 Jul 2026 18:11:43 +0200
Subject: Check the compound statement condition is a boolean

---
 boot/type_check.cc | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)

(limited to 'boot')

diff --git a/boot/type_check.cc b/boot/type_check.cc
index 761c4b2..9bab537 100644
--- a/boot/type_check.cc
+++ b/boot/type_check.cc
@@ -107,6 +107,9 @@ namespace elna::boot
             case kind::for_loop:
                 return "for-loop variable must be an array or a slice, got '"
                     + this->actual.to_string() + "'";
+            case kind::condition:
+                return "Condition must be a boolean, got '"
+                    + this->actual.to_string() + "'";
             default:
                 __builtin_unreachable();
         }
@@ -212,6 +215,16 @@ namespace elna::boot
         return true;
     }
 
+    void type_analysis_visitor::visit_and_validate_condition(expression& condition)
+    {
+        condition.accept(this);
+        if (!is_primitive_type(condition.type_decoration, "Bool"))
+        {
+            add_error<type_kind_error>(condition.position(),
+                    type_kind_error::kind::condition, condition.type_decoration);
+        }
+    }
+
     /*
      * Checks whether derived has base in its record parent chain.
      *
@@ -492,6 +505,61 @@ namespace elna::boot
         this->bag.leave();
     }
 
+    void type_analysis_visitor::visit(repeat_statement *statement)
+    {
+        visit_and_validate_condition(statement->condition());
+
+        for (auto *body_statement : statement->body)
+        {
+            body_statement->accept(this);
+        }
+    }
+
+    void type_analysis_visitor::visit(while_statement *statement)
+    {
+        visit_and_validate_condition(statement->branch().prerequisite());
+
+        for (auto *branch_statement : statement->branch().statements)
+        {
+            branch_statement->accept(this);
+        }
+        for (conditional_statements *branch : statement->branches)
+        {
+            visit_and_validate_condition(branch->prerequisite());
+
+            for (auto *branch_statement : branch->statements)
+            {
+                branch_statement->accept(this);
+            }
+        }
+    }
+
+    void type_analysis_visitor::visit(if_statement *statement)
+    {
+        visit_and_validate_condition(statement->branch().prerequisite());
+
+        for (auto *branch_statement : statement->branch().statements)
+        {
+            branch_statement->accept(this);
+        }
+        for (conditional_statements *branch : statement->branches)
+        {
+            visit_and_validate_condition(branch->prerequisite());
+
+            for (auto *branch_statement : branch->statements)
+            {
+                branch_statement->accept(this);
+            }
+        }
+        if (statement->alternative != nullptr)
+        {
+            for (auto *branch_statement : *statement->alternative)
+            {
+                branch_statement->accept(this);
+            }
+        }
+    }
+
     void type_analysis_visitor::visit(type_declaration *declaration)
     {
         std::vector<std::string> alias_path;
@@ -564,6 +632,7 @@ namespace elna::boot
                     type(std::make_shared<procedure_type>()),
                     call->callable().type_decoration);
         }
+        // else callable is not declared which is already reported.
     }
 
     void type_analysis_visitor::visit(record_constructor_expression *expression)
-- 
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