Robustly disallow overwriting builtin symbols (#817)

test/asm/builtin-overwrite.asm

@@ -0,0 +1,43 @@
+macro tickle
+; There once was a bug where overwriting worked only on the second try, so
+; try everything twice for good measure
+
+; Skip this syntax for EQUS, as it is invalid
+IF \2
+\1 = 0
+\1 = 0
+PRINTLN \1
+
+\1 EQU 0
+\1 EQU 0
+PRINTLN \1
+ENDC
+
+PURGE \1
+PURGE \1
+PRINTLN \1
+
+DEF \1 EQU 0
+DEF \1 EQU 0
+PRINTLN \1
+
+DEF \1 = 0
+DEF \1 = 0
+PRINTLN \1
+
+DEF \1 EQUS "hello"
+DEF \1 EQUS "hello"
+PRINTLN \1
+
+REDEF \1 = 0
+REDEF \1 = 0
+PRINTLN \1
+
+REDEF \1 EQUS "hello"
+REDEF \1 EQUS "hello"
+PRINTLN \1
+endm
+
+    ; Representative numeric and string builtins
+    tickle __LINE__, 1
+    tickle __FILE__, 0

test/asm/builtin-overwrite.err

@@ -0,0 +1,57 @@
+ERROR: builtin-overwrite.asm(42) -> builtin-overwrite.asm::tickle(7):
+    '__LINE__' already defined as constant at <builtin>
+ERROR: builtin-overwrite.asm(42) -> builtin-overwrite.asm::tickle(8):
+    '__LINE__' already defined as constant at <builtin>
+ERROR: builtin-overwrite.asm(42) -> builtin-overwrite.asm::tickle(11):
+    '__LINE__' already defined at <builtin>
+ERROR: builtin-overwrite.asm(42) -> builtin-overwrite.asm::tickle(12):
+    '__LINE__' already defined at <builtin>
+ERROR: builtin-overwrite.asm(42) -> builtin-overwrite.asm::tickle(16):
+    Built-in symbol '__LINE__' cannot be purged
+ERROR: builtin-overwrite.asm(42) -> builtin-overwrite.asm::tickle(17):
+    Built-in symbol '__LINE__' cannot be purged
+ERROR: builtin-overwrite.asm(42) -> builtin-overwrite.asm::tickle(20):
+    '__LINE__' already defined at <builtin>
+ERROR: builtin-overwrite.asm(42) -> builtin-overwrite.asm::tickle(21):
+    '__LINE__' already defined at <builtin>
+ERROR: builtin-overwrite.asm(42) -> builtin-overwrite.asm::tickle(24):
+    '__LINE__' already defined as constant at <builtin>
+ERROR: builtin-overwrite.asm(42) -> builtin-overwrite.asm::tickle(25):
+    '__LINE__' already defined as constant at <builtin>
+ERROR: builtin-overwrite.asm(42) -> builtin-overwrite.asm::tickle(28):
+    '__LINE__' already defined at <builtin>
+ERROR: builtin-overwrite.asm(42) -> builtin-overwrite.asm::tickle(29):
+    '__LINE__' already defined at <builtin>
+ERROR: builtin-overwrite.asm(42) -> builtin-overwrite.asm::tickle(32):
+    '__LINE__' already defined as constant at <builtin>
+ERROR: builtin-overwrite.asm(42) -> builtin-overwrite.asm::tickle(33):
+    '__LINE__' already defined as constant at <builtin>
+ERROR: builtin-overwrite.asm(42) -> builtin-overwrite.asm::tickle(36):
+    '__LINE__' already defined as non-EQUS at <builtin>
+ERROR: builtin-overwrite.asm(42) -> builtin-overwrite.asm::tickle(37):
+    '__LINE__' already defined as non-EQUS at <builtin>
+ERROR: builtin-overwrite.asm(43) -> builtin-overwrite.asm::tickle(16):
+    Built-in symbol '__FILE__' cannot be purged
+ERROR: builtin-overwrite.asm(43) -> builtin-overwrite.asm::tickle(17):
+    Built-in symbol '__FILE__' cannot be purged
+ERROR: builtin-overwrite.asm(43) -> builtin-overwrite.asm::tickle(20):
+    '__FILE__' already defined at <builtin>
+ERROR: builtin-overwrite.asm(43) -> builtin-overwrite.asm::tickle(21):
+    '__FILE__' already defined at <builtin>
+ERROR: builtin-overwrite.asm(43) -> builtin-overwrite.asm::tickle(24):
+    '__FILE__' already defined as constant at <builtin>
+ERROR: builtin-overwrite.asm(43) -> builtin-overwrite.asm::tickle(25):
+    '__FILE__' already defined as constant at <builtin>
+ERROR: builtin-overwrite.asm(43) -> builtin-overwrite.asm::tickle(28):
+    '__FILE__' already defined at <builtin>
+ERROR: builtin-overwrite.asm(43) -> builtin-overwrite.asm::tickle(29):
+    '__FILE__' already defined at <builtin>
+ERROR: builtin-overwrite.asm(43) -> builtin-overwrite.asm::tickle(32):
+    '__FILE__' already defined as constant at <builtin>
+ERROR: builtin-overwrite.asm(43) -> builtin-overwrite.asm::tickle(33):
+    '__FILE__' already defined as constant at <builtin>
+ERROR: builtin-overwrite.asm(43) -> builtin-overwrite.asm::tickle(36):
+    Built-in symbol '__FILE__' cannot be redefined
+ERROR: builtin-overwrite.asm(43) -> builtin-overwrite.asm::tickle(37):
+    Built-in symbol '__FILE__' cannot be redefined
+error: Assembly aborted (28 errors)!

test/asm/builtin-overwrite.out

@@ -0,0 +1,14 @@
+$9
+$D
+$12
+$16
+$1A
+$1E
+$22
+$26
+builtin-overwrite.asm
+builtin-overwrite.asm
+builtin-overwrite.asm
+builtin-overwrite.asm
+builtin-overwrite.asm
+builtin-overwrite.asm

test/asm/narg-overwrite.asm

@@ -1,2 +0,0 @@
-_NARG = 0
-_NARG = 0

test/asm/narg-overwrite.err

@@ -1,5 +0,0 @@
-ERROR: narg-overwrite.asm(1):
-    '_NARG' already defined as constant at <builtin>
-ERROR: narg-overwrite.asm(2):
-    '_NARG' already defined as constant at <builtin>
-error: Assembly aborted (2 errors)!