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fix(library/equations_compiler/compiler): eta-expand recursive occurrences earlier

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This commit is contained in:
Sebastian Ullrich 2018-12-18 12:49:05 +01:00
parent 861136d290
commit d214df63f1
2 changed files with 30 additions and 4 deletions
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29
src/library/equations_compiler/compiler.cpp
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@ -13,6 +13,7 @@ Author: Leonardo de Moura
#include "library/locals.h"
#include "library/util.h"
#include "library/replace_visitor.h"
#include "library/replace_visitor_with_tc.h"
#include "library/equations_compiler/compiler.h"
#include "library/equations_compiler/util.h"
#include "library/equations_compiler/structural_rec.h"
@ -320,9 +321,35 @@ static expr remove_aux_main_name(expr const & e) {
return e;
}
struct eta_expand_rec_apps_fn : public replace_visitor_with_tc {
eta_expand_rec_apps_fn(type_context_old & ctx): replace_visitor_with_tc(ctx) {}
virtual expr visit_local(expr const & e) {
if (is_rec(local_info(e))) {
expr e2 = m_ctx.eta_expand(e);
lean_assert(!is_local(e2));
return visit(e2);
}
return e;
}
virtual expr visit_app(expr const & e) {
expr const & fn = app_fn(e);
if (is_local(fn) && is_rec(local_info(fn))) {
// do not eta-expand `fn`
expr arg = visit(app_arg(e));
return mk_app(fn, arg);
} else {
return replace_visitor::visit_app(e);
}
}
};
static expr compile_equations_main(environment & env, elaborator & elab,
metavar_context & mctx, local_context const & lctx, expr const & _eqns, bool report_cexs) {
expr eqns = _eqns;
// all following code assumes that all recursive occurrences are applications
type_context_old ctx(env, mctx, lctx, elab.get_cache(), transparency_mode::Semireducible);
expr eqns = eta_expand_rec_apps_fn(ctx)(_eqns);
equations_header const & header = get_equations_header(eqns);
eqn_compiler_result r;
if (!header.m_is_meta && has_nested_rec(eqns)) {

5
src/library/equations_compiler/wf_rec.cpp
View file

@ -167,9 +167,8 @@ struct wf_rec_fn {
virtual expr visit_local(expr const & e) {
if (local_name(e) == local_name(m_fn)) {
expr e2 = m_ctx.eta_expand(e);
lean_assert(!is_local(e2));
return visit(e2);
/* unexpected occurrence of recursive function */
throw generic_exception(e, "unexpected occurrence of recursive function\n");
}
return e;
}