This change makes sure the compiler produces a proper error (rather
than crash) when compiling an (illegal) IF-expression where THEN-expression
is overloaded, and none of its interpretation is compatible with
the ELSE-expression.
The following compilation must display:
$ gcc -c badelse.adb
badelse.adb:4:50: type incompatible with that of "then" expression
package Badelse is
type K is (Unknown, Blue, Red);
type Tristate is (False, True, Unknown);
Boo : Boolean;
procedure P (X : K);
end Badelse;
package body Badelse is
procedure P (X : K) is
begin
Boo := (if X = Unknown then Unknown else X = Blue);
end P;
end Badelse;
Tested on x86_64-pc-linux-gnu, committed on trunk
2015-11-12 Thomas Quinot <qui...@adacore.com>
* sem_ch4.adb (analyze_If_Expression): Reject IF-expression where
THEN-expression is overloaded and none of its interpretation is
compatible with the ELSE-expression.
Index: sem_ch4.adb
===================================================================
--- sem_ch4.adb (revision 230239)
+++ sem_ch4.adb (working copy)
@@ -2191,6 +2191,17 @@
Get_Next_Interp (I, It);
end loop;
+
+ -- If no valid interpretation has been found, then the type of
+ -- the ELSE expression does not match any interpretation of
+ -- the THEN expression.
+
+ if Etype (N) = Any_Type then
+ Error_Msg_N
+ ("type incompatible with that of `THEN` expression",
+ Else_Expr);
+ return;
+ end if;
end;
end if;
end Analyze_If_Expression;
