It­Is­An­Error

Here's a list of places where R7RS-small says something "is an error".

1. 3.2 procedure domain errors

1. 3.3. reuse of auxiliary syntax

1. 3.3. violation of start-end constraints

2. 4 non-numeric datum labels

2. 4 forward references in datum labels

2. 4 recursion in datum labels

2. 4 circular code

3. 4 violations of immutability

4. 1.1 references to undefined variables

4. 1.3 () as code

4. 1.4. repeated variables in lambda lists

4. 1.6 set! of unbound variable

4. 2.1 => in cond or case doesn't accept one argument

4. 2.1 duplicated case keys

4. 2.2 repeated variables in let, letrec, let-values, let-values* lists or equivalent internal variable definitions

4. 2.2 direct recursion in letrec or letrec* or equivalent internal variable definitions

4. 2.2 mismatch between let-values formals and returned values

4. 2.4 repeated variables in do

4. 2.6 non-parameter in parameterize

4. 2.8 unquote-splicing of a non-list

4. 2.9 uncaught case in case-lambda

4. 3.1 repeated keywords in let-syntax

4. 3.2 non-identifiers in syntax-rules

4. 3.2 repeated pattern variable in syntax-rules

4. 3.2 unhandled syntax in syntax-rules

4. 3.2 unreconstructible syntax-rules output

5. 2 unknown identifiers in only, except, rename import specs

5. 2 importing an identifier more than once with different bindings

5. 2 redefining or mutating imported bindings

5. 2 referring to unimported identifiers

5. 3.3 duplicate variables in define-values

5. 4 use of a syntax keyword before its definition

5. 4 hopelessly muddled or ambiguous definitions

5. 5 duplicate field names in records

5. 5 undefined field name in record constructor

5. 5 invoke record accessor or mutator on record of wrong type

6. 2.3 use anything but an exact integer as a container index

6. 2.6 division by exact 0

6. 2.7 unusual conversion radix

6. 2.7 impossible conversion from number to string

6. 4 car or cdr of non-list

6. 4 list-ref, list-set!, list-tail invalid index

6. 4 alist is not an alist

6. 4 attempt to copy a circular list

6. 5 mutating symbol names

6. 7 violate forbidden-character restrictions

6. 7 string-ref, string-set! invalid index

6. 7 attempt to convert non-character to string or to fill string with non-character

6. 7 violate string-copy! restrictions

6. 8 vector-ref, vector-set! invalid index

6. 8 violate vector-copy! restrictions

6. 9 bytevector-u8-ref, byte-vector-u8-set! invalid index

6. 9 violate bytevector-copy! restrictions

6. 9 invalid UTF-8 byte sequences in utf8->string

6. 10 mapping procedures must accept as many containers as are available

6. 10 lists being mapped must not all be circular

6. 10 mapping procedures must not mutate inputs

6. 10 call/cc must accept one argument

6. 10 with-exception-handler handler and thunk arguments must accept a condition object and no arguments respectively

6. 13.1 procedure passed to a call procedure must accept one argument

6. 13.1 trying to get a string or bytevector out of a port that is not a string or bytevector port

6. 13.2 attempt operations on a closed port

6. 14 file names must be strings

6. 14 attempt to mutate command-line strings

6. 14 indecipherable environment variable

6. 14 attempt to mutate environment variables or values or features

7. 1 identifier starting with a combining character