From b7235b21c92168dd1c7456e82b3fcca71817defb Mon Sep 17 00:00:00 2001
From: Jonas Maebe <jonas@freepascal.org>
Date: Tue, 23 Jun 2009 18:42:53 +0000
Subject: [PATCH]   * no longer allow assigning values to typecasted
 properties, because in     case the getter is a function, the result is that
 first the getter is     called, and subsequently the temp holding the
 function result is     overwritten (thus not changing anything). This is
 Delphi-compatible,     and fixes tests/tbf/tb0214*

git-svn-id: trunk@13320 -
---
 .gitattributes        |  1 +
 compiler/htypechk.pas | 16 +++++++++++++++-
 tests/tbf/tb0214a.pp  | 23 +++++++++++++++++++++++
 3 files changed, 39 insertions(+), 1 deletion(-)
 create mode 100644 tests/tbf/tb0214a.pp

diff --git a/.gitattributes b/.gitattributes
index 1a20504f8c..b302a933af 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -6977,6 +6977,7 @@ tests/tbf/tb0211a.pp svneol=native#text/plain
 tests/tbf/tb0212.pp svneol=native#text/plain
 tests/tbf/tb0213.pp svneol=native#text/plain
 tests/tbf/tb0214.pp svneol=native#text/plain
+tests/tbf/tb0214a.pp svneol=native#text/plain
 tests/tbf/tb0215.pp svneol=native#text/plain
 tests/tbf/tb0215a.pp svneol=native#text/plain
 tests/tbf/tb0215b.pp svneol=native#text/plain
diff --git a/compiler/htypechk.pas b/compiler/htypechk.pas
index 5397b5ac36..5af9a62751 100644
--- a/compiler/htypechk.pas
+++ b/compiler/htypechk.pas
@@ -955,7 +955,8 @@ implementation
         gotvec,
         gotclass,
         gotdynarray,
-        gotderef : boolean;
+        gotderef,
+        gottypeconv : boolean;
         fromdef,
         todef    : tdef;
         errmsg,
@@ -976,6 +977,7 @@ implementation
         gotpointer:=false;
         gotdynarray:=false;
         gotstring:=false;
+        gottypeconv:=false;
         hp:=p;
         if not(valid_void in opts) and
            is_void(hp.resultdef) then
@@ -1013,6 +1015,17 @@ implementation
                       { same when we got a class and subscript (= deref) }
                       (gotclass and gotsubscript) or
                       (
+                       { allowing assignments to typecasted properties
+                           a) is Delphi-incompatible
+                           b) causes problems in case the getter is a function
+                              (because then the result of the getter is
+                               typecasted to this type, and then we "assign" to
+                               this typecasted function result) -> always
+                               disallow, since property accessors should be
+                               transparantly changeable to functions at all
+                               times
+                       }
+                       not(gottypeconv) and
                        not(gotsubscript and gotrecord) and
                        not(gotstring and gotvec)
                       ) then
@@ -1059,6 +1072,7 @@ implementation
                end;
              typeconvn :
                begin
+                 gottypeconv:=true;
                  { typecast sizes must match, exceptions:
                    - implicit typecast made by absolute
                    - from formaldef
diff --git a/tests/tbf/tb0214a.pp b/tests/tbf/tb0214a.pp
new file mode 100644
index 0000000000..2d8571624a
--- /dev/null
+++ b/tests/tbf/tb0214a.pp
@@ -0,0 +1,23 @@
+{ %fail }
+
+{$ifdef fpc}
+{$mode delphi}
+{$endif}
+
+type
+  tc = class
+   private
+    fl: longint;
+   public
+    property l: longint read fl write fl;
+  end;
+
+var
+  c: tc;
+begin
+  { should give an error stating that you cannot assign to left hand side }
+  { (generated code also does not result in an assignment)                }
+  cardinal(c.l):=cardinal(5);
+end.
+
+