exp_ch5.adb (Expand_N_Assignment_Statement): Do left-side validity check right away...

exp_ch5.adb (Expand_N_Assignment_Statement): Do left-side validity check right away so it does not get skipped for early...

2009-07-23  Robert Dewar  <dewar@adacore.com>

	* exp_ch5.adb (Expand_N_Assignment_Statement): Do left-side validity
	check right away so it does not get skipped for early returns, e.g.
	array assignments.
	(Expand_N_Assignment_Statement): Don't propagate Is_Known_Valid to
	left-side unless we really know the value is valid.

	* errout.adb, exp_ch3.adb, exp_disp.ads, sinfo.ads, exp_disp.adb: Minor
	reformatting. Minor code reorganization. Add comments.

From-SVN: r149978