all: fix error for comptime for in field with generic fn (fix #13409) (#13439)

Author: yuyi98

vlib/v/ast/ast.v

@@ -534,6 +534,7 @@ pub mut:
 	should_be_skipped  bool   // true for calls to `[if someflag?]` functions, when there is no `-d someflag`
 	concrete_types     []Type // concrete types, e.g. <int, string>
 	concrete_list_pos  token.Pos
+	raw_concrete_types []Type
 	free_receiver      bool // true if the receiver expression needs to be freed
 	scope              &Scope
 	from_embed_types   []Type // holds the type of the embed that the method is called from

vlib/v/checker/assign.v

@@ -135,6 +135,8 @@ pub fn (mut c Checker) assign_stmt(mut node ast.AssignStmt) {
 					}
 				}
 			}
+		} else if right is ast.ComptimeSelector {
+			right_type = c.comptime_fields_default_type
 		}
 		if is_decl {
 			// check generic struct init and return unwrap generic struct type

vlib/v/checker/checker.v

@@ -70,21 +70,22 @@ pub mut:
 	rlocked_names    []string // vars that are currently read-locked
 	in_for_count     int      // if checker is currently in a for loop
 	// checked_ident  string // to avoid infinite checker loops
-	should_abort   bool // when too many errors/warnings/notices are accumulated, .should_abort becomes true. It is checked in statement/expression loops, so the checker can return early, instead of wasting time.
-	returns        bool
-	scope_returns  bool
-	is_builtin_mod bool // true inside the 'builtin', 'os' or 'strconv' modules; TODO: remove the need for special casing this
-	is_generated   bool // true for `[generated] module xyz` .v files
-	inside_unsafe  bool // true inside `unsafe {}` blocks
-	inside_const   bool // true inside `const ( ... )` blocks
-	inside_anon_fn bool // true inside `fn() { ... }()`
-	inside_ref_lit bool // true inside `a := &something`
-	inside_defer   bool // true inside `defer {}` blocks
-	inside_fn_arg  bool // `a`, `b` in `a.f(b)`
-	inside_ct_attr bool // true inside `[if expr]`
-	skip_flags     bool // should `#flag` and `#include` be skipped
-	fn_level       int  // 0 for the top level, 1 for `fn abc() {}`, 2 for a nested fn, etc
-	ct_cond_stack  []ast.Expr
+	should_abort              bool // when too many errors/warnings/notices are accumulated, .should_abort becomes true. It is checked in statement/expression loops, so the checker can return early, instead of wasting time.
+	returns                   bool
+	scope_returns             bool
+	is_builtin_mod            bool // true inside the 'builtin', 'os' or 'strconv' modules; TODO: remove the need for special casing this
+	is_generated              bool // true for `[generated] module xyz` .v files
+	inside_unsafe             bool // true inside `unsafe {}` blocks
+	inside_const              bool // true inside `const ( ... )` blocks
+	inside_anon_fn            bool // true inside `fn() { ... }()`
+	inside_ref_lit            bool // true inside `a := &something`
+	inside_defer              bool // true inside `defer {}` blocks
+	inside_fn_arg             bool // `a`, `b` in `a.f(b)`
+	inside_ct_attr            bool // true inside `[if expr]`
+	inside_comptime_for_field bool
+	skip_flags                bool // should `#flag` and `#include` be skipped
+	fn_level                  int  // 0 for the top level, 1 for `fn abc() {}`, 2 for a nested fn, etc
+	ct_cond_stack             []ast.Expr
 mut:
 	stmt_level int // the nesting level inside each stmts list;
 	// .stmt_level is used to check for `evaluated but not used` ExprStmts like `1 << 1`

vlib/v/checker/comptime.v

@@ -109,10 +109,19 @@ fn (mut c Checker) comptime_for(node ast.ComptimeFor) {
 		c.error('unknown type `$sym.name`', node.typ_pos)
 	}
 	if node.kind == .fields {
-		c.comptime_fields_type[node.val_var] = node.typ
-		c.comptime_fields_default_type = node.typ
+		if sym.kind == .struct_ {
+			sym_info := sym.info as ast.Struct
+			c.inside_comptime_for_field = true
+			for field in sym_info.fields {
+				c.comptime_fields_type[node.val_var] = node.typ
+				c.comptime_fields_default_type = field.typ
+				c.stmts(node.stmts)
+			}
+			c.inside_comptime_for_field = false
+		}
+	} else {
+		c.stmts(node.stmts)
 	}
-	c.stmts(node.stmts)
 }
 
 // comptime const eval

vlib/v/checker/fn.v

@@ -428,6 +428,7 @@ pub fn (mut c Checker) fn_call(mut node ast.CallExpr, mut continue_check &bool)
 	}
 	mut has_generic := false // foo<T>() instead of foo<int>()
 	mut concrete_types := []ast.Type{}
+	node.concrete_types = node.raw_concrete_types
 	for concrete_type in node.concrete_types {
 		if concrete_type.has_flag(.generic) {
 			has_generic = true
@@ -777,6 +778,13 @@ pub fn (mut c Checker) fn_call(mut node ast.CallExpr, mut continue_check &bool)
 
 		typ := c.check_expr_opt_call(call_arg.expr, c.expr(call_arg.expr))
 		node.args[i].typ = typ
+		if c.inside_comptime_for_field {
+			if mut call_arg.expr is ast.Ident {
+				if mut call_arg.expr.obj is ast.Var {
+					node.args[i].typ = call_arg.expr.obj.typ
+				}
+			}
+		}
 		typ_sym := c.table.sym(typ)
 		param_typ_sym := c.table.sym(param.typ)
 		if func.is_variadic && typ.has_flag(.variadic) && node.args.len - 1 > i {
@@ -936,6 +944,9 @@ pub fn (mut c Checker) fn_call(mut node ast.CallExpr, mut continue_check &bool)
 						continue
 					}
 					c.check_expected_call_arg(utyp, unwrap_typ, node.language, call_arg) or {
+						if c.comptime_fields_type.len > 0 {
+							continue
+						}
 						c.error('$err.msg() in argument ${i + 1} to `$fn_name`', call_arg.pos)
 					}
 				}

vlib/v/checker/tests/comptime_for.out

@@ -18,20 +18,6 @@ vlib/v/checker/tests/comptime_for.vv:4:12: error: unknown type `T`
       |               ^
     5 |         $if f.typ is Huh {}
     6 |         $if f.typ is T {}
-vlib/v/checker/tests/comptime_for.vv:5:16: error: unknown type `Huh`
-    3 |     $for f in Huh.fields {}
-    4 |     $for f in T.fields {
-    5 |         $if f.typ is Huh {}
-      |                      ~~~
-    6 |         $if f.typ is T {}
-    7 |     }
-vlib/v/checker/tests/comptime_for.vv:6:16: error: unknown type `T`
-    4 |     $for f in T.fields {
-    5 |         $if f.typ is Huh {}
-    6 |         $if f.typ is T {}
-      |                      ^
-    7 |     }
-    8 |     _ = m
 vlib/v/checker/tests/comptime_for.vv:8:6: error: undefined ident: `m`
     6 |         $if f.typ is T {}
     7 |     }

vlib/v/checker/tests/comptime_for.vv

@@ -20,4 +20,6 @@ struct S1 {
 	i int
 }
 
-gf<S1>()
+fn main() {
+	gf<S1>()
+}