c++: Fix poor diagnostic for array initializer [PR93710]

A small improvement for an error in build_user_type_conversion_1:
instead of

array-init1.C:11:1: error: conversion from ‘long int’ to ‘A’ is ambiguous
   11 | };
      | ^

we will print

array-init1.C:8:3: error: conversion from ‘long int’ to ‘A’ is ambiguous
    8 |   0L,
      |   ^~

2020-02-12  Marek Polacek  <polacek@redhat.com>

	PR c++/93710 - poor diagnostic for array initializer.
	* call.c (build_user_type_conversion_1): Use cp_expr_loc_or_input_loc
	for an error call.

	* g++.dg/diagnostic/array-init1.C: New test.

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 6ac938b..f6b5517 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2020-02-15  Marek Polacek  <polacek@redhat.com>
+
+       PR c++/93710 - poor diagnostic for array initializer.
+       * call.c (build_user_type_conversion_1): Use cp_expr_loc_or_input_loc
+       for an error call.
+
 2020-02-15  Jason Merrill  <jason@redhat.com>
 
        PR c++/92556

diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index 51621b7..f47f96b 100644 (file)
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -4172,8 +4172,9 @@ build_user_type_conversion_1 (tree totype, tree expr, int flags,
       if (complain & tf_error)
        {
          auto_diagnostic_group d;
-         error ("conversion from %qH to %qI is ambiguous",
-                fromtype, totype);
+         error_at (cp_expr_loc_or_input_loc (expr),
+                   "conversion from %qH to %qI is ambiguous",
+                   fromtype, totype);
          print_z_candidates (location_of (expr), candidates);
        }
 

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index dca5b15..7c198dc 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-02-15  Marek Polacek  <polacek@redhat.com>
+
+       PR c++/93710 - poor diagnostic for array initializer.
+       * g++.dg/diagnostic/array-init1.C: New test.
+
 2020-02-15  Jason Merrill  <jason@redhat.com>
 
        * lib/target-supports.exp (check_effective_target_c++2a_only): Also

diff --git a/gcc/testsuite/g++.dg/diagnostic/array-init1.C b/gcc/testsuite/g++.dg/diagnostic/array-init1.C
new file mode 100644 (file)
index 0000000..78580ad
--- /dev/null
+++ b/gcc/testsuite/g++.dg/diagnostic/array-init1.C
@@ -0,0 +1,11 @@
+// PR c++/93710 - poor diagnostic for array initializer.
+
+struct A { A (int); A (char*); int i; };
+
+int x;
+
+A a1[] = {
+  0L, // { dg-error "3:conversion from .long int. to .A. is ambiguous" }
+  &x, // { dg-error "3:invalid conversion from .int\\*. to .int." }
+  __builtin_offsetof (A, i) // { dg-error "23:conversion from .long unsigned int. to .A. is ambiguous" }
+};