diagnostics.md

Diagnostics

Every diagnostic badc prints ends with its code and its name:

unit.c:3: warning: unused variable `x` [B2001] [-Wunused-variable]
unit.c:7: error: `)` expected after cast [B2020] [syntax]

The code and the name are stable: each stays with the diagnostic it was assigned, and a code is not renumbered. Either selects the row wherever a selector is accepted:

• -W<name> / -Wno-<name> report or ignore a controllable row, -Werror=<name> / -Wno-error=<name> raise it to an error or put it back, -Werror raises every warning, -w silences every warning. -Wall, -Wextra and -Wpedantic turn on the groups of the same names, following gcc's split. A code spelled B2001 is accepted wherever a name is. A gcc or clang warning badc does not implement is accepted, and turning it on reports B7012; any other unknown name is refused, except in -Wno-<name>, which gcc accepts for any name.
• #pragma GCC diagnostic ignored "-W<name>" (also warning, error, push, pop), #pragma clang diagnostic ... and MSVC's #pragma warning(disable | error | default | once | suppress | push | pop : <number>) apply from the pragma's position; an MSVC number names the row it is an alias of.
• badc --explain <selector> prints one row with its aliases; badc --list-diagnostics prints this table.

A hard row is always an error: its site has no way to continue, and no option changes it. A note is advisory. The default level and the groups may change between releases; the code and the name do not.

This file is generated by scripts/diagnostics_doc.py from tests/diagnostics/catalog.txt, which badc --list-diagnostics regenerates.

code	name	default	class	groups	description
B1001	unknown-directive	warning	controllable	default	a # line naming no directive badc implements; the line is dropped
B1002	#warnings	warning	controllable	default	a #warning directive reached in an active conditional block
B1003	malformed-directive	warning	controllable	default	a macro-expanded #include or #line operand that does not reparse
B1004	unknown-pragmas	warning	controllable	default,all	a #pragma badc does not implement; the directive is ignored
B1005	pragma-syntax	warning	controllable	default	a diagnostic pragma badc implements whose operand is malformed
B1006	pragma-pop-without-push	warning	controllable	default	a diagnostic-pragma pop with no matching push
B1007	ignored-pragma-intrinsic	warning	controllable	default	a #pragma intrinsic naming a function badc has no intrinsic for; the name stays an ordinary call
B1008	date-time	ignore	controllable	-	a use of __DATE__ or __TIME__, whose expansion changes from one build to the next
B1009	undef	ignore	controllable	-	an identifier that names no macro evaluated in a #if or #elif expression, where it is 0
B1010	directive	error	hard	-	a directive whose operand the preprocessor cannot process, a directive preprocessed input does not take, or a conditional directive with no #if to match
B1011	invalid-pragma	error	hard	-	a pragma badc implements whose operand cannot be applied
B1012	invalid-token	error	hard	-	a character sequence that forms no token: a malformed constant, escape sequence or universal character name
B1013	error-directive	error	hard	-	a #error directive reached in an active conditional block
B1014	macro	error	hard	-	a macro definition or invocation C99 6.10.3 rejects: an argument count the definition does not take, ## at either end of a replacement list
B1015	macro-redefined	warning	controllable	default	a macro redefined with another kind, parameter list or replacement list (C99 6.10.3p2) outside a system header; the new definition replaces the old
B2001	unused-variable	ignore	controllable	all	a variable declared and never used
B2002	unused-parameter	ignore	controllable	extra	a parameter never used in the function body
B2003	unused-but-set-variable	ignore	controllable	all	a variable that is only ever assigned to
B2004	unused-function	ignore	controllable	all	a function with internal linkage that is defined and never referenced
B2005	implicit-function-declaration	warning	controllable	default	a function used before a prototype declares it, so its return type is int
B2006	undefined-function	warning	controllable	default	an initializer names a static function this unit declares and never defines
B2007	redeclaration-mismatch	warning	controllable	default	a function redeclaration incompatible under C99 that GNU C accepts: an implicit int body for a void declaration, an old-style definition matching its prototype only before promotion
B2008	attributes	warning	controllable	default	an attribute the declaration cannot carry, so it is ignored
B2009	ignored-asm-label	warning	controllable	default	an assembler name on a declaration that has no symbol to rename
B2010	shadowed-binding	warning	controllable	default	a #pragma binding for a name an earlier binding already claimed
B2011	implicit-int	error	controllable	default	a declaration or type name with no type specifier, whose type defaults to int
B2012	inline-asm	warning	controllable	default	an asm statement that lists the stack pointer as clobbered or writes it through an output, where GNU C requires it to hold its value
B2013	visibility	warning	controllable	default	a tag declared in a parameter list, whose scope ends with the declaration or definition
B2014	strict-prototypes	ignore	controllable	-	a function declarator whose empty or identifier list declares no prototype, outside a cast and a definition an earlier prototype covers
B2015	missing-prototypes	ignore	controllable	-	an external function definition, neither inline nor main, that no file-scope declaration with a prototype precedes
B2016	missing-declarations	ignore	controllable	-	an external function definition, neither inline nor main, that no file-scope declaration precedes
B2017	implicit-fallthrough=5	ignore	controllable	-	a statement completing normally into the case or default label after it, which no fallthrough attribute statement annotates
B2018	vla-larger-than	ignore	controllable	-	under optimization, a variable-length array whose size the size expression does not bound by the -Wvla-larger-than= byte count
B2020	syntax	error	hard	-	a token the grammar does not admit at its position; the parser has no resynchronisation point
B2021	invalid-declaration	error	hard	-	a declaration a C99 constraint rejects: a redefinition, conflicting types, an incomplete object, a bit-field width or an alignment out of range
B2022	undeclared-identifier	error	hard	-	a name no declaration in scope introduces
B2023	static-assert	error	hard	-	a static assertion whose controlling expression is zero
B2024	incomplete-element-type	error	hard	-	an array whose element type is incomplete: an array of unknown size, void, or a tag declared without its body
B3001	int-conversion	warning	controllable	default	an integer and a pointer exchanged with no cast
B3002	incompatible-struct-types	warning	controllable	default	an aggregate or enumerated type used where a different one is expected
B3003	return-type	ignore	controllable	all	control reaches the end of a value-returning function
B3004	too-few-arguments	warning	controllable	default	a call passing fewer arguments than an old-style definition or a libc binding's prototype declares
B3005	too-many-arguments	warning	controllable	default	a call passing more arguments than an old-style definition or a libc binding's prototype declares
B3006	long-double-abi (retired)	warning	controllable	default	a long double argument passed in a format this target's ABI does not use
B3007	dead-store	ignore	controllable	-	a value assigned to a local and replaced before any read
B3008	switch-outside-range	warning	controllable	default	a case label whose value lies outside the range of the controlling expression's type before promotion
B3009	empty-case-range	warning	controllable	default	a GNU case range lo ... hi whose low bound exceeds its high bound in the promoted type of the controlling expression; the label is dropped
B3010	constant-conversion	warning	controllable	default	an integer constant converted implicitly to an integer type or a bit-field whose width holds the value at neither signedness
B3011	incompatible-pointer-types-discards-qualifiers	warning	controllable	default	a pointer assigned, initialized, passed or returned as a pointer to a type that differs from the one it points to only in the qualifiers of a type further down: T ** as const T **
B3012	switch-bool	warning	controllable	default	a switch on a boolean value with a case label outside 0 and 1, or with a default beside labels covering both
B3013	excess-initializers	warning	controllable	default	a string literal longer than the array, member or row it initializes, a terminator aside; the characters past the bound are dropped
B3015	cast-function-type	ignore	controllable	extra	a cast between pointers to function types whose returns or common leading parameters differ other than as pointers or as integers of one precision
B3016	designated-init	warning	controllable	default	an initializer element with no designator for a member of a struct declared designated_init
B3017	enum-conversion	ignore	controllable	extra	a value of one enumerated type, or a constant of one, assigned, initialized, passed or returned as another enumerated type
B3014	builtin-argument-range	warning	controllable	default	an integer constant operand of a builtin outside the values the builtin takes; 0 is used in its place
B3020	invalid-operands	error	hard	-	an operator applied to operands its constraints reject, or a non-lvalue where an lvalue is required
B3021	constant-expression	error	hard	-	an expression that must be constant and is not, or one the compiler cannot evaluate at translation time
B3022	invalid-initializer	error	hard	-	an initializer C99 6.7.8 rejects: a mismatched brace form, a designator naming nothing, an index out of range
B3023	invalid-arguments	error	hard	-	a call with arguments its callee does not take: a count other than a prototype's, or a builtin's or intrinsic's operand it rejects
B3024	invalid-statement	error	hard	-	a statement outside the construct it needs: break outside a loop, case outside a switch, a goto to no label, a jump into a statement expression or into the scope of a variably modified or cleanup object
B3025	incompatible-types	error	hard	-	a value of a type no implicit conversion takes to the type required: an aggregate assigned, passed or returned as another
B3026	return-mismatch	error	controllable	default	a return with a value in a function returning void, or with none in a function returning a value
B3027	void-value	error	hard	-	the value of a void expression used: as an operand, an argument, an initializer, an assigned or returned value, or a controlling expression
B3028	controlling-expression	error	hard	-	a controlling expression of a type its statement does not take: a non-scalar if, while, do or for condition, a non-integer switch expression
B3029	incompatible-pointer-types	error	controllable	default	a pointer assigned, initialized, passed or returned as a pointer to a type incompatible with the type it points to, neither side a pointer to void
B3030	pointer-difference	error	hard	-	a subtraction of two pointers that do not point to qualified or unqualified versions of compatible types
B3031	discarded-qualifiers	warning	controllable	default	a pointer assigned, initialized, passed or returned as a pointer to a type without a const or volatile the original pointed-to type has
B3032	pointer-sign	warning	controllable	default	a pointer assigned, initialized, passed or returned as a pointer to an integer type that differs from the one it points to only in signedness
B3033	modifiable-lvalue	error	hard	-	an assignment, compound assignment, ++ or -- whose operand is const-qualified, or is a structure or union with a const member
B4001	unsupported	error	hard	-	a well-formed construct badc does not implement
B4002	limit	error	hard	-	a translation limit badc imposes: nesting depth, include depth, alignment
B4003	inline	ignore	controllable	-	a function the source declared inline that the optimizer left out of line
B4004	always-inline	warning	controllable	default	a function marked always_inline or __forceinline that the optimizer left out of line
B4005	frame-larger-than	warning	controllable	default	a function whose stack frame exceeds the -Wframe-larger-than= bound; saved registers and the frame record count, alloca and variable-length arrays do not
B5001	asm-syntax	error	hard	-	an asm statement whose operand list, constraints or template does not parse
B5002	assembler	error	hard	-	an instruction or directive the assembler cannot parse or encode for the target
B6001	orphan-section	warning	controllable	default	an input section no script rule names, placed by the linker's own rule
B6002	missing-entry	warning	controllable	default	no input defines the entry symbol, so the image enters at the first text address
B6003	merged-section-access	warning	controllable	default	a relocation reaches past the end of the merged section it names
B6004	execstack	warning	controllable	default	the image's stack is executable because an input's .note.GNU-stack asks for it, or because -z execstack does under --warn-execstack
B6005	rwx-segment	warning	controllable	default	a segment the image loads is readable, writable and executable, or its thread-local segment executable
B6006	local-import	warning	controllable	default	a reference to the import-address slot __imp_X of a symbol X the link defines, which resolves to the definition
B6007	text-relocation	warning	controllable	default	a dynamic relocation writes into a read-only segment, which the loader makes writable to apply it (DT_TEXTREL)
B6010	undefined-symbol	error	hard	-	a reference no input object, archive or shared library defines
B6011	duplicate-symbol	error	hard	-	more than one input defines the same symbol
B6012	relocation	error	hard	-	a relocation the linker cannot apply, or a value its field cannot hold
B6013	linker-script	error	hard	-	a linker script badc cannot parse, or a construct it does not implement
B6014	malformed-input	error	hard	-	an input object, archive or shared library the reader cannot make sense of
B6015	object-format	error	hard	-	a construct the selected object format cannot express
B6016	link	error	hard	-	a link-time failure with no more specific row
B7001	unknown-argument	error	hard	-	command-line option or operand the driver does not implement
B7002	unknown-warning-option	warning	controllable	default	a diagnostic pragma names a selector that is neither in the catalogue nor a gcc or clang warning
B7003	unused-command-line-argument	ignore	controllable	all,extra	an accepted option that selects nothing in the mode the command line picked
B7004	no-input-files	error	hard	-	the command line names nothing to compile, assemble or link
B7005	input-unreadable	error	hard	-	an input file the driver cannot read
B7006	output-unwritable	error	hard	-	the driver cannot write the file it was asked to produce
B7007	unsupported-option	error	controllable	default	an option badc parses but declines in the mode the command line picked
B7008	link-pragma-ignored	warning	controllable	default	a link request from a source pragma that an object file does not carry
B7009	cross-target-output	warning	note	-	the image is for another host and will not run where it was built
B7010	freestanding-import	warning	controllable	default	a freestanding image binds a shared-library symbol, so it runs through the dynamic loader
B7011	dwarf-output	warning	controllable	default	a -gdwarf option asks for a DWARF version or format the emitter does not produce
B7012	unimplemented-warning-option	warning	controllable	default	a diagnostic pragma or a -W option turns on a gcc or clang warning that badc does not implement, so it has no effect
B9001	internal-error	error	hard	-	an invariant inside badc did not hold