better location for compound members

regression/ansi-c/Incomplete_Type1/incomplete_component.c

@@ -0,0 +1,10 @@
+typedef struct incomplete_struct t;
+
+struct
+{
+  t x;
+};
+
+int main()
+{
+}

regression/ansi-c/Incomplete_Type1/incomplete_component.desc

@@ -0,0 +1,9 @@
+CORE
+incomplete_component.c
+
+^EXIT=(1|64)$
+^SIGNAL=0$
+^CONVERSION ERROR$
+^incomplete_component\.c:5:1: error: incomplete type not permitted here$
+--
+^warning: ignoring

src/ansi-c/c_typecheck_type.cpp

@@ -872,8 +872,13 @@ void c_typecheck_baset::typecheck_compound_body(
         struct_union_typet::componentt new_component(
           declarator.get_base_name(), declaration.full_type(declarator));
 
-        new_component.add_source_location()=
-          declarator.source_location();
+        // There may be a declarator, which we use as location for
+        // the component. Otherwise, use location of the declaration.
+        const source_locationt source_location =
+          declarator.get_name().empty() ? declaration.source_location()
+                                        : declarator.source_location();
+
+        new_component.add_source_location() = source_location;
         new_component.set_pretty_name(declarator.get_base_name());
 
         typecheck_type(new_component.type());
@@ -882,7 +887,7 @@ void c_typecheck_baset::typecheck_compound_body(
            (new_component.type().id()!=ID_array ||
             !to_array_type(new_component.type()).is_incomplete()))
         {
-          error().source_location=new_component.type().source_location();
+          error().source_location = source_location;
           error() << "incomplete type not permitted here" << eom;
           throw 0;
         }

src/ansi-c/parser.y

@@ -1634,7 +1634,8 @@ member_declaration:
         | member_default_declaring_list ';'
         | ';' /* empty declaration */
         {
-          init($$, ID_declaration);
+          $$=$1; // the ';' becomes the location of the declaration
+          stack($$).id(ID_declaration);
         }
         | static_assert_declaration ';'
         ;
@@ -1651,6 +1652,7 @@ member_default_declaring_list:
 
           init($$, ID_declaration);
           to_ansi_c_declaration(stack($$)).set_is_member(true);
+          stack($$).add_source_location()=stack($2).source_location();
           stack($$).type().swap(stack($2));
           PARSER.add_declarator(stack($$), stack($3));
         }
@@ -1686,6 +1688,7 @@ member_declaring_list:
 
           init($$, ID_declaration);
           to_ansi_c_declaration(stack($$)).set_is_member(true);
+          stack($$).add_source_location()=stack($2).source_location();
           stack($$).type().swap(stack($2));
           PARSER.add_declarator(stack($$), stack($3));
         }