From 9460f9f14dd68eb59d36f758272be936300a0440 Mon Sep 17 00:00:00 2001
From: lemon <lsof@mailbox.org>
Date: Sun, 7 Aug 2022 17:57:22 +0200
Subject: fix template accessing future environment

---
 bootstrap/all.h     |  6 +++++-
 bootstrap/env.c     | 16 ++++++++++++----
 bootstrap/parse.c   | 19 ++++++++++++++-----
 bootstrap/test2.cff |  8 +++++---
 4 files changed, 36 insertions(+), 13 deletions(-)

diff --git a/bootstrap/all.h b/bootstrap/all.h
index 5302a07..fb6bfe6 100644
--- a/bootstrap/all.h
+++ b/bootstrap/all.h
@@ -134,6 +134,8 @@ struct parser {
    const struct type *targty;
    bool used_targty;
    bool is_header;
+   bool save_envage;
+   int envage;
 };
 
 enum typetype {
@@ -262,8 +264,10 @@ struct decl {
             const struct type *ty;
          } *cache;
          struct toktree toks;
+         int envage;
       } tepl;
    };
+   int age;
 };
 
 struct teplparam {
@@ -528,7 +532,7 @@ bool isnumtype(const struct type *a);
 const struct type *typeof2(const struct type *a, const struct type *b);
 
 /** env.c **/
-struct decl *envfind(const struct env *, const char *name);
+struct decl *envfind(const struct env *, int age, const char *name);
 struct decl *envput(struct env *, const struct decl *decl);
 struct env *mkenv(const struct env *parent);
 
diff --git a/bootstrap/env.c b/bootstrap/env.c
index ddd06b2..b3652fa 100644
--- a/bootstrap/env.c
+++ b/bootstrap/env.c
@@ -2,14 +2,19 @@
 
 
 struct decl *
-envfind(const struct env *env, const char *name) {
+envfind(const struct env *env, int age, const char *name) {
+   int eage = INT_MAX;
+
+again:
    if (!env)
       return NULL;
    for (struct decls *decls = env->decls; decls; decls = decls->next) {
-      if (!strcmp(decls->decl.name, name))
+      if (eage >= decls->decl.age && !strcmp(decls->decl.name, name))
          return &decls->decl;
    }
-   return envfind(env->parent, name);
+   env = env->parent;
+   eage = env && env->parent ? eage : age;
+   goto again;
 }
 
 static bool
@@ -24,7 +29,9 @@ envput(struct env *env, const struct decl *decl) {
      .decls = env->decls
    };
    struct decl *d0;
-   if ((d0 = envfind(&env_noparent, decl->name))) {
+   static int age;
+
+   if ((d0 = envfind(&env_noparent, INT_MAX, decl->name))) {
       // modify existing forward declarations?
       for (int kind = TYstruct; kind <= TYunion; ++kind) {
          if (d0->t == Dtype && d0->ty->t == kind
@@ -58,6 +65,7 @@ envput(struct env *env, const struct decl *decl) {
    decls = xcalloc(1, sizeof *decls);
    decls->next = env->decls;
    decls->decl = *decl;
+   decls->decl.age = age++;
    env->decls = decls;
    return &decls->decl;
 }
diff --git a/bootstrap/parse.c b/bootstrap/parse.c
index 7b2e007..99560d8 100644
--- a/bootstrap/parse.c
+++ b/bootstrap/parse.c
@@ -539,20 +539,22 @@ popenv(struct parser *P) {
 static struct decl *
 putdecl(struct parser *P, struct span espan, const struct decl *decl) {
    struct decl *ret;
-   if (envfind(P->primenv, decl->name))
+   if (envfind(P->primenv, INT_MAX, decl->name))
       fatal(P, espan, "cannot shadow primitive `%s'", decl->name);
    if (!(ret = envput(P->curenv, decl)))
       fatal(P, decl->span,
             "cannot shadow earlier incompatible declaration of `%s'", decl->name);
+   if (!P->save_envage)
+      P->envage = MAX(P->envage, ret->age);
    return ret;
 }
 
 static const struct decl *
 finddecl(struct parser *P, const char *name) {
    const struct decl *decl;
-   if ((decl = envfind(P->primenv, name)))
+   if ((decl = envfind(P->primenv, INT_MAX, name)))
       return decl;
-   return envfind(P->curenv, name);
+   return envfind(P->curenv, P->envage, name);
 }
 
 static struct expr parseexpr(struct parser *P);
@@ -684,6 +686,7 @@ parseexpandtepl(struct parser *P, struct tepl *tepl) {
    }
 
    struct env env = { tepl->env };
+
    WITH_TMPCHANGE(struct env *, P->curenv, &env) {
       struct decl *decl;
       expan.args.d = args;
@@ -691,8 +694,11 @@ parseexpandtepl(struct parser *P, struct tepl *tepl) {
       expan.toks = tepl->toks;
       ++P->expanno;
       P->curexpan = memcpy(xmalloc(sizeof expan), &expan, sizeof expan);
-      ty = parseagg(P, tepl->name, tepl->tkind, &decl);
+      WITH_TMPCHANGE(int, P->envage, tepl->envage)
+         WITH_TMPCHANGE(int, P->save_envage, 1)
+            ty = parseagg(P, tepl->name, tepl->tkind, &decl);
    }
+   free(env.decls);
    memcpy(&((struct type *)ty)->agg.tpargs, &tpargs, sizeof tpargs);
    cache = xcalloc(sizeof *cache, 1);
    cache->next = tepl->cache;
@@ -2443,7 +2449,7 @@ parseagg(struct parser *P, const char *name, int kind, struct decl **retdecl) {
          int iid;
          struct env env_noparent = *P->curenv;
          env_noparent.parent = NULL;
-         struct decl *decl = (struct decl *)envfind(&env_noparent, name);
+         struct decl *decl = (struct decl *)envfind(&env_noparent, P->envage, name);
          if (decl && decl->ty->t == kind)
             iid = decl->ty->agg.id;
          else
@@ -2586,6 +2592,7 @@ parseaggtepl(struct parser *P, int kind, const char *name) {
    }
 
    tepl.env = P->curenv;
+   tepl.envage = P->envage;
    vec_slice_cpy(&tepl.params, &params);
    vec_slice_cpy(&tepl.toks, &toks);
    return tepl;
@@ -2705,6 +2712,8 @@ parsedecl(decl_yielder_t yield, void *yarg, struct parser *P, bool toplevel) {
          decl.t = Dtype;
          decl.ty = parseagg(P, decl.name, kind, &decl2);
       } else {
+         if (!toplevel)
+            fatal(P, tok.span, "template definition inside function");
          decl.t = Dtepl;
          decl.tepl = parseaggtepl(P, kind, decl.name);
       }
diff --git a/bootstrap/test2.cff b/bootstrap/test2.cff
index 3532f4a..356312c 100644
--- a/bootstrap/test2.cff
+++ b/bootstrap/test2.cff
@@ -8,12 +8,14 @@ struct Node<T> {
    }
 }
 
+def X = 7 + 2;
+
 struct Bit<T> {
-   fn neg(x T) T { return ~x; }
+   fn neg(x T) T { return ~x + X; }
+   !fn neg(x T) T { return ~x + Y; }
 }
 
-def X = 7 + 2,
-   Y = 3.3;
+def Y = 3.3;
 
 extern fn main() void {
    let n Node<int> = {#null, 0};
-- 
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