lower top-level statements in such a way that the front-end knows (#2…

…6304)

their values are not used

fixes most false positives in the deprecation for using the value of `.=`

src/ast.c

@@ -829,7 +829,11 @@ jl_value_t *jl_parse_eval_all(const char *fname,
  form = jl_expand_macros(form, inmodule, NULL, 0);
  expression = julia_to_scm(fl_ctx, form);
  }
- expression = fl_applyn(fl_ctx, 1, symbol_value(symbol(fl_ctx, "jl-expand-to-thunk")), expression);
+ // expand non-final expressions in statement position (value unused)
+ expression =
+ fl_applyn(fl_ctx, 1,
+ symbol_value(symbol(fl_ctx, iscons(cdr_(ast)) ? "jl-expand-to-thunk-stmt" : "jl-expand-to-thunk")),
+ expression);
  }
  jl_get_ptls_states()->world_age = jl_world_counter;
  form = scm_to_julia(fl_ctx, expression, inmodule);
@@ -1115,6 +1119,18 @@ JL_DLLEXPORT jl_value_t *jl_expand(jl_value_t *expr, jl_module_t *inmodule)
  return expr;
 }
 
+// expand in a context where the expression value is unused
+JL_DLLEXPORT jl_value_t *jl_expand_stmt(jl_value_t *expr, jl_module_t *inmodule)
+{
+ JL_TIMING(LOWERING);
+ JL_GC_PUSH1(&expr);
+ expr = jl_copy_ast(expr);
+ expr = jl_expand_macros(expr, inmodule, NULL, 0);
+ expr = jl_call_scm_on_ast("jl-expand-to-thunk-stmt", expr, inmodule);
+ JL_GC_POP();
+ return expr;
+}
+
 
 #ifdef __cplusplus
 }

src/jlfrontend.scm

@@ -94,12 +94,14 @@
 
 (define *in-expand* #f)
 
+(define (toplevel-only-expr? e)
+ (and (pair? e)
+ (or (memq (car e) '(toplevel line module import importall using export
+ error incomplete))
+ (and (eq? (car e) 'global) (every symbol? (cdr e))))))
+
 (define (expand-toplevel-expr e)
- (cond ((or (atom? e)
- (and (pair? e)
- (or (memq (car e) '(toplevel line module import importall using export
- error incomplete))
- (and (eq? (car e) 'global) (every symbol? (cdr e))))))
+ (cond ((or (atom? e) (toplevel-only-expr? e))
  (if (underscore-symbol? e)
  (syntax-deprecation "underscores as an rvalue" "" #f))
  e)
@@ -207,6 +209,11 @@
  (parser-wrap (lambda ()
  (expand-toplevel-expr expr))))
 
+(define (jl-expand-to-thunk-stmt expr)
+ (jl-expand-to-thunk (if (toplevel-only-expr? expr)
+ expr
+ `(block ,expr (null)))))
+
 ; run whole frontend on a string. useful for testing.
 (define (fe str)
  (expand-toplevel-expr (julia-parse str)))

src/julia.h

@@ -1450,6 +1450,7 @@ JL_DLLEXPORT jl_value_t *jl_parse_string(const char *str, size_t len,
 JL_DLLEXPORT jl_value_t *jl_load_file_string(const char *text, size_t len,
  char *filename, jl_module_t *inmodule);
 JL_DLLEXPORT jl_value_t *jl_expand(jl_value_t *expr, jl_module_t *inmodule);
+JL_DLLEXPORT jl_value_t *jl_expand_stmt(jl_value_t *expr, jl_module_t *inmodule);
 JL_DLLEXPORT jl_value_t *jl_eval_string(const char *str);
 
 // external libraries

src/toplevel.c

@@ -228,7 +228,7 @@ jl_value_t *jl_eval_module_expr(jl_module_t *parent_module, jl_expr_t *ex)
  for (int i = 0; i < jl_array_len(exprs); i++) {
  // process toplevel form
  ptls->world_age = jl_world_counter;
- form = jl_expand(jl_array_ptr_ref(exprs, i), newm);
+ form = jl_expand_stmt(jl_array_ptr_ref(exprs, i), newm);
  ptls->world_age = jl_world_counter;
  (void)jl_toplevel_eval_flex(newm, form, 1, 1);
  }

test/deprecation_exec.jl

@@ -209,6 +209,18 @@ end
  # #6080
  @test_deprecated r"Syntax `&argument`.*is deprecated" Meta.lower(@__MODULE__, :(ccall(:a, Cvoid, (Cint,), &x)))
 
+ @test_logs eval(:(module DotEqualsDep
+ a=[1,2]
+ a.=3
+ 0
+ end))
+ @test_logs include_string(@__MODULE__, """
+ a=[1,2]
+ a.=3
+ 0""")
+ @test_deprecated include_string(@__MODULE__, """
+ a=[1,2]
+ a.=3""")
 end
 
 module LogTest