fbc: fix bad error recovery of overloaded operator []

For example:
type T extends object
	declare operator []( byval index as integer) as any ptr
end type

dim as T x
x[0].invalid

/'
fbc 1.09:
  Aborting due to runtime error 12 ("segmentation violation" signal)

fbc 1.10:
  error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before 'invalid' in 'x[0].invalid'
'/

Author: jayrm

changelog.txt

@@ -125,7 +125,7 @@ Version 1.10.0
 - fbc: discard assignments and constructor calls in initializers that would write outside of the target when emitting initializer lists - previously, up-casted initializers were writing beyond the limits of the target and trashing memory
 - fix regression due to previous change on sf.net #917: optimization of 'm += s'.  The optimization failed to consider 's = s + expr' where expr might contain 's'.  In such a case, the optimization cannot be applied.
 - fbc: basic-macros: improve the handling of optional parens in function like macros by ending a macro argument list on the number of arguments expected (non-variadic macros only).
-- fbc: bad error recovery after overloaded operator [] caused compiler crash, for example if overloaded operator [] is found but can't be used due to mixing const and non-const types.
+- fbc: bad error recovery after overloaded operator [] caused compiler crash, for example if overloaded operator [] is found but can't be used due to mixing const and non-const types, or invalid members
 - fbc: improve error message 215 to indicate that only static members can be accessed from parameter intializers as well as static functions
 - fbc: #cmdline "-c ..." needs to restart parser since code generation is affected.  The implicit main was being emitted even when '-c' was give in #cmdline and was working differently than when '-c' given on the actual command line. 
 - fbc: extend lifetime of temporary variables in WITH TYPE(...) expressions to the END WITH statement

src/compiler/parser-expr-variable.bas

@@ -698,6 +698,12 @@ function cMemberDeref _
 				if( lexGetToken( ) = CHAR_DOT ) then
 					lexSkipToken( LEXCHECK_NOPERIOD )
 
+					'' member access on overloaded []'s return type must be UDT
+					if( astGetDataType( varexpr ) <> FB_DATATYPE_STRUCT ) then
+						errReport( FB_ERRMSG_EXPECTEDUDT, TRUE )
+						exit function
+					end if
+
 					'' MemberAccess
 					varexpr = cMemberAccess( astGetFullType( varexpr ), _
 					                         astGetSubType( varexpr ), varexpr )

tests/syntax/err-expected-udt.bas

@@ -0,0 +1,69 @@
+'' FB_ERRMSG_EXPECTEDUDT
+
+namespace n1
+	type T extends object
+		declare operator []( byval index as integer) as any ptr
+	end type
+
+	sub proc
+		dim as T x
+#print "-- 1 error expected"
+		print x[0].invalid
+	end sub
+end namespace
+
+namespace n2
+	type T
+		i as T ptr
+	end type
+
+	sub proc
+		dim x as T
+#print "-- 1 error expected"
+		print x.i.i
+	end sub
+end namespace
+
+namespace n3
+	sub proc
+		dim x as integer
+#print "-- 1 error expected"
+		print x.invalid
+	end sub
+end namespace
+
+namespace n4
+	type T
+		i as integer
+	end type
+
+	sub proc
+		dim x as T
+#print "-- 1 error expected"
+		print peek(@x).invalid
+	end sub
+end namespace
+
+namespace n5
+	function f() as any ptr
+		function = 0
+	end function
+
+	sub proc
+#print "-- 1 error expected"
+		print f().invalid
+	end sub
+end namespace
+
+namespace n6
+	type T
+		i as any ptr
+	end type
+
+	sub proc
+		dim x as T
+		dim px as T ptr = @x
+#print "-- 1 error expected"
+		print px->i.i
+	end sub
+end namespace

tests/syntax/r/dos/err-expected-udt.txt

@@ -0,0 +1,12 @@
+-- 1 error expected
+err-expected-udt.bas(11) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before 'invalid' in 'print x[0].invalid'
+-- 1 error expected
+err-expected-udt.bas(23) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print x.i.i'
+-- 1 error expected
+err-expected-udt.bas(31) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print x.invalid'
+-- 1 error expected
+err-expected-udt.bas(43) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print peek(@x).invalid'
+-- 1 error expected
+err-expected-udt.bas(54) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print f().invalid'
+-- 1 error expected
+err-expected-udt.bas(67) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print px->i.i'

tests/syntax/r/linux-x86/err-expected-udt.txt

@@ -0,0 +1,12 @@
+-- 1 error expected
+err-expected-udt.bas(11) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before 'invalid' in 'print x[0].invalid'
+-- 1 error expected
+err-expected-udt.bas(23) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print x.i.i'
+-- 1 error expected
+err-expected-udt.bas(31) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print x.invalid'
+-- 1 error expected
+err-expected-udt.bas(43) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print peek(@x).invalid'
+-- 1 error expected
+err-expected-udt.bas(54) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print f().invalid'
+-- 1 error expected
+err-expected-udt.bas(67) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print px->i.i'

tests/syntax/r/linux-x86_64/err-expected-udt.txt

@@ -0,0 +1,12 @@
+-- 1 error expected
+err-expected-udt.bas(11) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before 'invalid' in 'print x[0].invalid'
+-- 1 error expected
+err-expected-udt.bas(23) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print x.i.i'
+-- 1 error expected
+err-expected-udt.bas(31) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print x.invalid'
+-- 1 error expected
+err-expected-udt.bas(43) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print peek(@x).invalid'
+-- 1 error expected
+err-expected-udt.bas(54) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print f().invalid'
+-- 1 error expected
+err-expected-udt.bas(67) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print px->i.i'

tests/syntax/r/win32/err-expected-udt.txt

@@ -0,0 +1,12 @@
+-- 1 error expected
+err-expected-udt.bas(11) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before 'invalid' in 'print x[0].invalid'
+-- 1 error expected
+err-expected-udt.bas(23) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print x.i.i'
+-- 1 error expected
+err-expected-udt.bas(31) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print x.invalid'
+-- 1 error expected
+err-expected-udt.bas(43) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print peek(@x).invalid'
+-- 1 error expected
+err-expected-udt.bas(54) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print f().invalid'
+-- 1 error expected
+err-expected-udt.bas(67) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print px->i.i'

tests/syntax/r/win64/err-expected-udt.txt

@@ -0,0 +1,12 @@
+-- 1 error expected
+err-expected-udt.bas(11) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before 'invalid' in 'print x[0].invalid'
+-- 1 error expected
+err-expected-udt.bas(23) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print x.i.i'
+-- 1 error expected
+err-expected-udt.bas(31) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print x.invalid'
+-- 1 error expected
+err-expected-udt.bas(43) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print peek(@x).invalid'
+-- 1 error expected
+err-expected-udt.bas(54) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print f().invalid'
+-- 1 error expected
+err-expected-udt.bas(67) error 265: Symbol not a CLASS, ENUM, TYPE or UNION type, before '.' in 'print px->i.i'