fix(parser): Part 3-4 - Fix remaining infinite loops in parser subsystems

Part 3 (included):
- parser_box.hako: Fix semicolon consumption loop (lines 401-421)

Part 4 (systematic fix of 7 files):
- parser_number_scan_box.hako: Fix scan_int digit scanning loop
- parser_literal_box.hako: Fix parse_map and parse_array loops (2 loops)
- parser_peek_box.hako: Fix peek expression arms parsing loop
- parser_control_box.hako: Fix parse_block and semicolon loops (2 loops)
- parser_exception_box.hako: Fix try/catch clauses loop
- parser_stmt_box.hako: Fix using statement namespace parsing loop

Root cause: MirBuilder bug with loop(flag == 0/1) + nested if-else
- Generated broken MIR with PHI self-references
- Caused infinite loops in VM execution

Solution: Convert all problematic loops to MirBuilder-friendly pattern:
  loop(true) { if condition { continue } else { break } }

Test results: ✅ Stage-1 CLI now completes without timeout
- Exit code: 0
- MIR dump created successfully
- parse_program2 ws_init: 1 iteration (was infinite)

Total loops fixed across all parts: 18 loops in 11 files

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

lang/src/compiler/parser/expr/parser_literal_box.hako

@@ -10,54 +10,49 @@ static box ParserLiteralBox {
     local j = i + 1  // skip opening '{'
     local out = "["
     local first = 1
-    local cont = 1
-    local guard = 0
-    local max = 400000
 
-    loop(cont == 1) {
+    // MirBuilder-friendly: explicit break instead of flag
-      if guard > max { cont = 0 } else { guard = guard + 1 }
+    loop(true) {
       j = ctx.skip_ws(src, j)
 
-      if j >= n {
+      if j >= n { break }
-        cont = 0
+
+      if src.substring(j, j+1) == "}" {
+        j = j + 1
+        break
+      }
+
+      // key (string only for Stage-2)
+      if src.substring(j, j+1) != "\"" {
+        // degrade by skipping one char to avoid infinite loop
+        j = j + 1
+        continue
+      }
+
+      local key_raw = ctx.read_string_lit(src, j)
+      j = ctx.gpos_get()
+      j = ctx.skip_ws(src, j)
+      if src.substring(j, j+1) == ":" { j = j + 1 }
+      j = ctx.skip_ws(src, j)
+      local val_json = ctx.parse_expr2(src, j)
+      j = ctx.gpos_get()
+      local key_json = "{\"type\":\"Str\",\"value\":\"" + ctx.esc_json(key_raw) + "\"}"
+
+      if first == 1 {
+        out = out + key_json + "," + val_json
+        first = 0
       } else {
-        if src.substring(j, j+1) == "}" {
+        out = out + "," + key_json + "," + val_json
-          j = j + 1
+      }
-          cont = 0
-        } else {
-          // key (string only for Stage-2)
-          if src.substring(j, j+1) != "\"" {
-            // degrade by skipping one char to avoid infinite loop
-            j = j + 1
-            continue
-          }
 
-          local key_raw = ctx.read_string_lit(src, j)
+      // optional comma
-          j = ctx.gpos_get()
+      local before2 = j
-          j = ctx.skip_ws(src, j)
+      j = ctx.skip_ws(src, j)
-          if src.substring(j, j+1) == ":" { j = j + 1 }
+      if j < n && src.substring(j, j+1) == "," { j = j + 1 }
-          j = ctx.skip_ws(src, j)
-          local val_json = ctx.parse_expr2(src, j)
-          j = ctx.gpos_get()
-          local key_json = "{\"type\":\"Str\",\"value\":\"" + ctx.esc_json(key_raw) + "\"}"
 
-          if first == 1 {
+      // progress guard (in case of malformed input)
-            out = out + key_json + "," + val_json
+      if j <= before2 {
-            first = 0
+        if j < n { j = j + 1 } else { j = n }
-          } else {
-            out = out + "," + key_json + "," + val_json
-          }
-
-          // optional comma
-          local before2 = j
-          j = ctx.skip_ws(src, j)
-          if j < n && src.substring(j, j+1) == "," { j = j + 1 }
-
-          // progress guard (in case of malformed input)
-          if j <= before2 {
-            if j < n { j = j + 1 } else { j = n }
-          }
-        }
       }
     }
 
@@ -72,42 +67,37 @@ static box ParserLiteralBox {
     local j = i + 1  // skip opening '['
     local out = "["
     local first = 1
-    local cont = 1
-    local guard = 0
-    local max = 400000
 
-    loop(cont == 1) {
+    // MirBuilder-friendly: explicit break instead of flag
-      if guard > max { cont = 0 } else { guard = guard + 1 }
+    loop(true) {
       j = ctx.skip_ws(src, j)
 
-      if j >= n {
+      if j >= n { break }
-        cont = 0
+
+      if src.substring(j, j+1) == "]" {
+        j = j + 1
+        break
+      }
+
+      local before = j
+      local ej = ctx.parse_expr2(src, j)
+      j = ctx.gpos_get()
+
+      if first == 1 {
+        out = out + ej
+        first = 0
       } else {
-        if src.substring(j, j+1) == "]" {
+        out = out + "," + ej
-          j = j + 1
+      }
-          cont = 0
-        } else {
-          local before = j
-          local ej = ctx.parse_expr2(src, j)
-          j = ctx.gpos_get()
 
-          if first == 1 {
+      // optional comma+whitespace
-            out = out + ej
+      local before2 = j
-            first = 0
+      j = ctx.skip_ws(src, j)
-          } else {
+      if j < n && src.substring(j, j+1) == "," { j = j + 1 }
-            out = out + "," + ej
-          }
 
-          // optional comma+whitespace
+      // progress guard
-          local before2 = j
+      if j <= before {
-          j = ctx.skip_ws(src, j)
+        if j < n { j = j + 1 } else { j = n }
-          if j < n && src.substring(j, j+1) == "," { j = j + 1 }
-
-          // progress guard
-          if j <= before {
-            if j < n { j = j + 1 } else { j = n }
-          }
-        }
       }
     }
 

lang/src/compiler/parser/expr/parser_peek_box.hako

@@ -21,77 +21,73 @@ static box ParserPeekBox {
     local arms_json = "["
     local first_arm = 1
     local else_json = null
-    local contp = 1
-    local guardp = 0
-    local maxp = 400000
 
-    loop(contp == 1) {
+    // MirBuilder-friendly: explicit break instead of flag
-      if guardp > maxp { contp = 0 } else { guardp = guardp + 1 }
+    loop(true) {
       j = ctx.skip_ws(src, j)
 
-      if j >= n {
+      if j >= n { break }
-        contp = 0
+
-      } else {
+      if src.substring(j, j+1) == "}" {
-        if src.substring(j, j+1) == "}" {
+        j = j + 1
+        break
+      }
+
+      // else arm or labeled arm
+      if ctx.starts_with_kw(src, j, "else") == 1 {
+        j = j + 4
+        j = ctx.skip_ws(src, j)
+        if src.substring(j, j+2) == "=>" { j = j + 2 }
+        j = ctx.skip_ws(src, j)
+
+        // else body may be a block or bare expr
+        if src.substring(j, j+1) == "{" {
           j = j + 1
-          contp = 0
+          j = ctx.skip_ws(src, j)
+          else_json = ctx.parse_expr2(src, j)
+          j = ctx.gpos_get()
+          j = ctx.skip_ws(src, j)
+          if src.substring(j, j+1) == "}" { j = j + 1 }
         } else {
-          // else arm or labeled arm
+          else_json = ctx.parse_expr2(src, j)
-          if ctx.starts_with_kw(src, j, "else") == 1 {
+          j = ctx.gpos_get()
-            j = j + 4
-            j = ctx.skip_ws(src, j)
-            if src.substring(j, j+2) == "=>" { j = j + 2 }
-            j = ctx.skip_ws(src, j)
-
-            // else body may be a block or bare expr
-            if src.substring(j, j+1) == "{" {
-              j = j + 1
-              j = ctx.skip_ws(src, j)
-              else_json = ctx.parse_expr2(src, j)
-              j = ctx.gpos_get()
-              j = ctx.skip_ws(src, j)
-              if src.substring(j, j+1) == "}" { j = j + 1 }
-            } else {
-              else_json = ctx.parse_expr2(src, j)
-              j = ctx.gpos_get()
-            }
-          } else {
-            // labeled arm: string literal label
-            if src.substring(j, j+1) != "\"" {
-              // degrade safely to avoid infinite loop
-              j = j + 1
-              continue
-            }
-
-            local label_raw = ctx.read_string_lit(src, j)
-            j = ctx.gpos_get()
-            j = ctx.skip_ws(src, j)
-            if src.substring(j, j+2) == "=>" { j = j + 2 }
-            j = ctx.skip_ws(src, j)
-
-            // arm expr: block or bare expr
-            local expr_json = "{\"type\":\"Int\",\"value\":0}"
-            if src.substring(j, j+1) == "{" {
-              j = j + 1
-              j = ctx.skip_ws(src, j)
-              expr_json = ctx.parse_expr2(src, j)
-              j = ctx.gpos_get()
-              j = ctx.skip_ws(src, j)
-              if src.substring(j, j+1) == "}" { j = j + 1 }
-            } else {
-              expr_json = ctx.parse_expr2(src, j)
-              j = ctx.gpos_get()
-            }
-
-            local arm_json = "{\"label\":\"" + ctx.esc_json(label_raw) + "\",\"expr\":" + expr_json + "}"
-            if first_arm == 1 {
-              arms_json = arms_json + arm_json
-              first_arm = 0
-            } else {
-              arms_json = arms_json + "," + arm_json
-            }
-          }
         }
+        continue
+      }
+
+      // labeled arm: string literal label
+      if src.substring(j, j+1) != "\"" {
+        // degrade safely to avoid infinite loop
+        j = j + 1
+        continue
+      }
+
+      local label_raw = ctx.read_string_lit(src, j)
+      j = ctx.gpos_get()
+      j = ctx.skip_ws(src, j)
+      if src.substring(j, j+2) == "=>" { j = j + 2 }
+      j = ctx.skip_ws(src, j)
+
+      // arm expr: block or bare expr
+      local expr_json = "{\"type\":\"Int\",\"value\":0}"
+      if src.substring(j, j+1) == "{" {
+        j = j + 1
+        j = ctx.skip_ws(src, j)
+        expr_json = ctx.parse_expr2(src, j)
+        j = ctx.gpos_get()
+        j = ctx.skip_ws(src, j)
+        if src.substring(j, j+1) == "}" { j = j + 1 }
+      } else {
+        expr_json = ctx.parse_expr2(src, j)
+        j = ctx.gpos_get()
+      }
+
+      local arm_json = "{\"label\":\"" + ctx.esc_json(label_raw) + "\",\"expr\":" + expr_json + "}"
+      if first_arm == 1 {
+        arms_json = arms_json + arm_json
+        first_arm = 0
+      } else {
+        arms_json = arms_json + "," + arm_json
       }
     }
 

lang/src/compiler/parser/parser_box.hako

@@ -398,18 +398,8 @@ box ParserBox {
         print("[parser/trace:program2] i=" + ("" + i) + " stmt_len=" + ("" + s.length()) + " guard=" + ("" + guard_prog))
       }
 
-      // ===== 6) CONSUME OPTIONAL SEMICOLONS =====
+      // ===== 6) CONSUME OPTIONAL SEMICOLONS - MirBuilder-friendly =====
-      local done_semi = 0
+      loop(true) {
-      local guard_semi = 0
-      local max_semi = 100000
-
-      loop(done_semi == 0) {
-        if guard_semi > max_semi {
-          done_semi = 1
-        } else {
-          guard_semi = guard_semi + 1
-        }
-
         local before_semi = i
 
         // Inline ws skip
@@ -424,13 +414,10 @@ box ParserBox {
 
         if i < n && src.substring(i, i+1) == ";" {
           i = i + 1
-        } else {
+          continue
-          done_semi = 1
         }
 
-        if i == before_semi {
+        break
-          done_semi = 1
-        }
       }
 
       // ===== 7) EMIT STATEMENT =====

lang/src/compiler/parser/scan/parser_number_scan_box.hako

@@ -9,14 +9,13 @@ static box ParserNumberScanBox {
     if src == null { return "{\"type\":\"Int\",\"value\":0}@" + ParserCommonUtilsBox.i2s(i) }
     local n = src.length()
     local j = i
-    local cont = 1
+    // MirBuilder-friendly: explicit continue/break instead of flag
-    local guard = 0
+    loop(j < n) {
-    local max = 100000
+      if ParserCommonUtilsBox.is_digit(src.substring(j, j+1)) {
-    loop(cont == 1) {
+        j = j + 1
-      if guard > max { cont = 0 } else { guard = guard + 1 }
+        continue
-      if j < n {
+      }
-        if ParserCommonUtilsBox.is_digit(src.substring(j, j+1)) { j = j + 1 } else { cont = 0 }
+      break
-      } else { cont = 0 }
     }
     local s = src.substring(i, j)
     if s.length() == 0 { s = "0" }

lang/src/compiler/parser/stmt/parser_control_box.hako

@@ -250,48 +250,45 @@ static box ParserControlBox {
 
     local body = "["
     local first = 1
-    local cont_block = 1
 
-    loop(cont_block == 1) {
+    // MirBuilder-friendly: explicit break instead of flag
+    loop(true) {
       j = ctx.skip_ws(src, j)
 
-      if j >= src.length() {
+      if j >= src.length() { break }
-        cont_block = 0
+
-      } else {
+      if src.substring(j, j+1) == "}" {
-        if src.substring(j, j+1) == "}" {
+        j = j + 1
+        break
+      }
+
+      local start_j = j
+      local s = ctx.parse_stmt2(src, j)
+      j = ctx.gpos_get()
+
+      // Progress guard: ensure forward movement to avoid infinite loop on malformed input
+      if j <= start_j {
+        if j < src.length() { j = j + 1 } else { j = src.length() }
+        ctx.gpos_set(j)
+      }
+
+      // consume optional semicolons (ASI minimal) - MirBuilder-friendly
+      loop(true) {
+        local before = j
+        j = ctx.skip_ws(src, j)
+        if j < src.length() && src.substring(j, j+1) == ";" {
           j = j + 1
-          cont_block = 0
+          continue
+        }
+        break
+      }
+
+      if s.length() > 0 {
+        if first == 1 {
+          body = body + s
+          first = 0
         } else {
-          local start_j = j
+          body = body + "," + s
-          local s = ctx.parse_stmt2(src, j)
-          j = ctx.gpos_get()
-
-          // Progress guard: ensure forward movement to avoid infinite loop on malformed input
-          if j <= start_j {
-            if j < src.length() { j = j + 1 } else { j = src.length() }
-            ctx.gpos_set(j)
-          }
-
-          // consume optional semicolons (ASI minimal)
-          local done = 0
-          local guard = 0
-          local max = 100000
-          loop(done == 0) {
-            if guard > max { done = 1 } else { guard = guard + 1 }
-            local before = j
-            j = ctx.skip_ws(src, j)
-            if j < src.length() && src.substring(j, j+1) == ";" { j = j + 1 } else { done = 1 }
-            if j == before { done = 1 }
-          }
-
-          if s.length() > 0 {
-            if first == 1 {
-              body = body + s
-              first = 0
-            } else {
-              body = body + "," + s
-            }
-          }
         }
       }
     }

lang/src/compiler/parser/stmt/parser_exception_box.hako

@@ -41,15 +41,13 @@ static box ParserExceptionBox {
     local catches_json = "["
     local catch_first = 1
 
-    // zero or more catch
+    // zero or more catch - MirBuilder-friendly
-    local guard_ct = 0
+    loop(true) {
-    local max_ct = 100
-    local cont_ct = 1
-    loop(cont_ct == 1) {
-      if guard_ct > max_ct { cont_ct = 0 } else { guard_ct = guard_ct + 1 }
       j = ctx.skip_ws(src, j)
 
-      if ctx.starts_with_kw(src, j, "catch") == 1 {
+      if ctx.starts_with_kw(src, j, "catch") != 1 { break }
+
+      {
         j = j + 5
         j = ctx.skip_ws(src, j)
         local catch_type = null
@@ -112,8 +110,6 @@ static box ParserExceptionBox {
             catch_first = 0
           }
         }
-      } else {
-        cont_ct = 0
       }
     }
 

lang/src/compiler/parser/stmt/parser_stmt_box.hako

@@ -344,19 +344,16 @@ static box ParserStmtBox {
         local at = idp.lastIndexOf("@")
         local name = idp.substring(0, at)
         j = ctx.to_int(idp.substring(at+1, idp.length()))
-        local cont = 1
+        // MirBuilder-friendly: explicit break instead of flag
-        loop(cont == 1) {
+        loop(true) {
           j = ParserStringUtilsBox.skip_ws(src, j)
-          if src.substring(j, j+1) == "." {
+          if src.substring(j, j+1) != "." { break }
-            j = j + 1
+          j = j + 1
-            j = ParserStringUtilsBox.skip_ws(src, j)
+          j = ParserStringUtilsBox.skip_ws(src, j)
-            idp = ctx.read_ident2(src, j)
+          idp = ctx.read_ident2(src, j)
-            at = idp.lastIndexOf("@")
+          at = idp.lastIndexOf("@")
-            name = name + "." + idp.substring(0, at)
+          name = name + "." + idp.substring(0, at)
-            j = ctx.to_int(idp.substring(at+1, idp.length()))
+          j = ctx.to_int(idp.substring(at+1, idp.length()))
-          } else {
-            cont = 0
-          }
         }
         j = ParserStringUtilsBox.skip_ws(src, j)
         local alias2 = null