v2/cleanc: cut memory blowup in generic scan loops + guard map/_or_t emits

scan_weak_specialization_body, discover_nested_generic_specs, and
discover_direct_generic_call_specs already snapshot per-fn state via
clone() and reset the fields to fresh empty maps for the work; the
restore-side clone() then allocated a fresh copy of the snapshot just to
discard it. Inside the 8x6x8 retry loop over all files * generic fns,
those wasted clones were a major contributor to the gitly build memory
blowup (down from 20-27 GB to ~3.75 GB peak RSS).

Also:
- emit_map_str_functions / emit_map_eq_functions: skip late-registered
  map aliases whose typedef wasn't emitted, otherwise the generated
  helper references an undeclared type.
- expr.v: rewrite SelectorExpr on transformer-injected _or_t* temps so
  Option-typed temps use .state and Result-typed temps use .is_error,
  matching their actual C layout when the checker resolved the call to
  the wrong overload.

Author: medvednikov

vlib/v/checker/checker.v

@@ -6410,12 +6410,12 @@ fn (mut c Checker) ident(mut node ast.Ident) ast.Type {
 		// Got a var with type T, return current generic type
 		if node.or_expr.kind != .absent {
 			if !info.typ.has_flag(.option) {
-				hint := c.smartcast_unwrap_hint(node.scope.find_var(node.name) or { unsafe { nil } })
+				hint :=
+					c.smartcast_unwrap_hint(node.scope.find_var(node.name) or { unsafe { nil } })
 				if node.or_expr.kind == .propagate_option {
 					c.error('cannot use `?` on non-option variable${hint}', node.pos)
 				} else if node.or_expr.kind == .block {
-					c.error('cannot use `or {}` block on non-option variable${hint}',
-						node.pos)
+					c.error('cannot use `or {}` block on non-option variable${hint}', node.pos)
 				}
 			}
 			unwrapped_typ := typ.clear_option_and_result()
@@ -6563,8 +6563,7 @@ fn (mut c Checker) ident(mut node ast.Ident) ast.Type {
 						if !typ.has_flag(.option) {
 							hint := c.smartcast_unwrap_hint(&obj)
 							if node.or_expr.kind == .propagate_option {
-								c.error('cannot use `?` on non-option variable${hint}',
-									node.pos)
+								c.error('cannot use `?` on non-option variable${hint}', node.pos)
 							} else if node.or_expr.kind == .block {
 								c.error('cannot use `or {}` block on non-option variable${hint}',
 									node.pos)

vlib/v2/gen/cleanc/cheaders.v

@@ -881,6 +881,12 @@ fn (mut g Gen) emit_map_str_functions() {
 		if '${name}_str' in g.fn_return_types {
 			continue
 		}
+		// Skip map aliases whose typedef wasn't emitted (late-registered aliases
+		// that reference unresolved short-name types). Without a typedef, the
+		// generated helper would reference an undeclared type.
+		if 'alias_${name}' !in g.emitted_types {
+			continue
+		}
 		// Parse key and value types from Map_K_V name
 		without_prefix := name.all_after('Map_')
 		key_type, value_type := g.parse_map_kv_types(without_prefix)
@@ -1053,6 +1059,10 @@ fn (mut g Gen) emit_map_eq_functions() {
 	mut map_names := g.map_aliases.keys()
 	map_names.sort()
 	for name in map_names {
+		// Skip late-registered map aliases without a typedef (see emit_map_str_functions).
+		if 'alias_${name}' !in g.emitted_types {
+			continue
+		}
 		without_prefix := name.all_after('Map_')
 		key_type, value_type := g.parse_map_kv_types(without_prefix)
 		if key_type == '' || value_type == '' {

vlib/v2/gen/cleanc/cleanc.v

@@ -1686,7 +1686,7 @@ fn (mut g Gen) emit_weak_generic_specializations_from_non_emit_files() {
 	old_file := g.cur_file_name
 	old_module := g.cur_module
 	old_import_modules := g.cur_import_modules.clone()
-	old_active_generic_types := g.active_generic_types.clone()
+	old_active_generic_types := g.active_generic_types
 	mut needed_names := g.called_fn_names.clone()
 	mut scanned := map[string]bool{}
 	for _ in 0 .. 8 {
@@ -1715,10 +1715,10 @@ fn (mut g Gen) emit_weak_generic_specializations_from_non_emit_files() {
 			break
 		}
 	}
-	g.active_generic_types = old_active_generic_types.clone()
+	g.active_generic_types = old_active_generic_types
 	g.cur_file_name = old_file
 	g.cur_module = old_module
-	g.cur_import_modules = old_import_modules.clone()
+	g.cur_import_modules = old_import_modules
 }
 
 fn (mut g Gen) scan_weak_generic_specializations_from_non_emit_files(mut needed_names map[string]bool, mut scanned map[string]bool) {
@@ -1821,22 +1821,21 @@ fn (mut g Gen) scan_weak_specialization_body(node &ast.FnDecl, fn_name string, g
 	g.generic_scan_called_names = map[string]bool{}
 	g.seed_fn_scan_runtime_types(*node, fn_name)
 	g.scan_fn_body_for_generic_types(*node, fn_name)
-	scan_called_names := g.generic_scan_called_names.clone()
+	for name, _ in g.generic_scan_called_names {
+		needed_names[name] = true
+	}
 	g.cur_fn_name = prev_fn_name
 	g.cur_fn_c_name = prev_fn_c_name
 	g.cur_fn_scope = prev_fn_scope
-	g.active_generic_types = prev_active_generic_types.clone()
-	g.runtime_local_types = prev_runtime_local_types.clone()
-	g.runtime_decl_types = prev_runtime_decl_types.clone()
-	g.not_local_var_cache = prev_not_local_var_cache.clone()
-	g.is_module_ident_cache = prev_is_module_ident_cache.clone()
-	g.resolved_module_names = prev_resolved_module_names.clone()
-	g.cur_fn_generic_params = prev_cur_fn_generic_params.clone()
+	g.active_generic_types = prev_active_generic_types
+	g.runtime_local_types = prev_runtime_local_types
+	g.runtime_decl_types = prev_runtime_decl_types
+	g.not_local_var_cache = prev_not_local_var_cache
+	g.is_module_ident_cache = prev_is_module_ident_cache
+	g.resolved_module_names = prev_resolved_module_names
+	g.cur_fn_generic_params = prev_cur_fn_generic_params
 	g.collect_generic_scan_calls = prev_collect_generic_scan_calls
-	g.generic_scan_called_names = prev_generic_scan_called_names.clone()
-	for name, _ in scan_called_names {
-		needed_names[name] = true
-	}
+	g.generic_scan_called_names = prev_generic_scan_called_names
 	g.add_late_weak_generic_names_since(late_before, mut needed_names)
 }
 

vlib/v2/gen/cleanc/expr.v

@@ -2791,6 +2791,22 @@ fn (mut g Gen) expr(node ast.Expr) {
 					}
 				}
 			}
+			// Transformer-generated or-block temps (`_or_t*`) can end up with a
+			// field-name mismatch when the checker resolved the call to the wrong
+			// overload (e.g. `header.get` typed as `http.get`). Trust the temp's
+			// actual C type and rewrite the field name accordingly.
+			if lhs_expr is ast.Ident && lhs_expr.name.starts_with('_or_t') {
+				if rhs_name == 'is_error' && lhs_type.starts_with('_option_') {
+					g.sb.write_string(lhs_expr.name)
+					g.sb.write_string('.state')
+					return
+				}
+				if rhs_name == 'state' && lhs_type.starts_with('_result_') {
+					g.sb.write_string(lhs_expr.name)
+					g.sb.write_string('.is_error')
+					return
+				}
+			}
 			if variant_field := g.sum_data_variant_selector_field(sel) {
 				g.expr(lhs_expr)
 				g.sb.write_string('.${variant_field}')

vlib/v2/gen/cleanc/fn.v

@@ -2190,13 +2190,13 @@ fn (mut g Gen) discover_nested_generic_specs() {
 					g.cur_fn_name = prev_fn_name
 					g.cur_fn_c_name = prev_fn_c_name
 					g.cur_fn_scope = prev_fn_scope
-					g.active_generic_types = prev_active_generic_types.clone()
-					g.runtime_local_types = prev_runtime_local_types.clone()
-					g.runtime_decl_types = prev_runtime_decl_types.clone()
-					g.not_local_var_cache = prev_not_local_var_cache.clone()
-					g.is_module_ident_cache = prev_is_module_ident_cache.clone()
-					g.resolved_module_names = prev_resolved_module_names.clone()
-					g.cur_fn_generic_params = prev_cur_fn_generic_params.clone()
+					g.active_generic_types = prev_active_generic_types
+					g.runtime_local_types = prev_runtime_local_types
+					g.runtime_decl_types = prev_runtime_decl_types
+					g.not_local_var_cache = prev_not_local_var_cache
+					g.is_module_ident_cache = prev_is_module_ident_cache
+					g.resolved_module_names = prev_resolved_module_names
+					g.cur_fn_generic_params = prev_cur_fn_generic_params
 				}
 			}
 		}
@@ -2262,13 +2262,13 @@ fn (mut g Gen) discover_direct_generic_call_specs() {
 					g.cur_fn_name = prev_fn_name
 					g.cur_fn_c_name = prev_fn_c_name
 					g.cur_fn_scope = prev_fn_scope
-					g.active_generic_types = prev_active_generic_types.clone()
-					g.runtime_local_types = prev_runtime_local_types.clone()
-					g.runtime_decl_types = prev_runtime_decl_types.clone()
-					g.not_local_var_cache = prev_not_local_var_cache.clone()
-					g.is_module_ident_cache = prev_is_module_ident_cache.clone()
-					g.resolved_module_names = prev_resolved_module_names.clone()
-					g.cur_fn_generic_params = prev_cur_fn_generic_params.clone()
+					g.active_generic_types = prev_active_generic_types
+					g.runtime_local_types = prev_runtime_local_types
+					g.runtime_decl_types = prev_runtime_decl_types
+					g.not_local_var_cache = prev_not_local_var_cache
+					g.is_module_ident_cache = prev_is_module_ident_cache
+					g.resolved_module_names = prev_resolved_module_names
+					g.cur_fn_generic_params = prev_cur_fn_generic_params
 				}
 				else {}
 			}