Semantic Rules Catalog

This document enumerates semantic rules derived from the language spec. Rules are grouped by stage to enable incremental implementation. Each rule includes a code, severity, and intent. Adjust codes as needed.

Stage 0: Definition & Signature Collection

E1001 DuplicateTypeName (Error)

• Trigger: two type/enum/contract items share the same name in a module.
• Source: 02-types, 09-contracts, 10-name-resolution.

E1002 DuplicateEnumVariant (Error)

• Trigger: enum defines the same variant name twice.
• Source: 04-enums-and-match.

E1003 DuplicateContractMethod (Error)

• Trigger: contract defines duplicate method signatures.
• Source: 09-contracts.

E1004 ConflictingEmbeddedContract (Error)

• Trigger: embedded contracts introduce conflicting methods (same name, incompatible signature).
• Source: 09-contracts (conflict example).

E1005 UnknownTypeInDefinition (Error)

• Trigger: field/parameter types reference unknown type names.
• Source: 02-types, 10-name-resolution.

E1006 DuplicateItemName (Error)

• Trigger: duplicate function/module/use item name in the same module scope.
• Source: 10-name-resolution.

Stage 1: Name Resolution & Scopes

E1101 UndefinedVariable (Error)

• Trigger: identifier used in expression has no binding in scope.
• Source: 10-name-resolution.

E1102 DuplicateBinding (Error)

• Trigger: let/parameter binding duplicates a name in the same scope.
• Source: 10-name-resolution.

W1103 ShadowingBinding (Warning)

• Trigger: binding shadows a name from an outer scope.
• Source: 10-name-resolution.

E1104 AmbiguousImport (Error)

• Trigger: two use imports bring the same name without aliasing.
• Source: 10-name-resolution (ambiguous import error).

E1105 UnknownImportPath (Error)

• Trigger: use path does not resolve to a module/item.
• Source: 06-modules-and-visibility, 10-name-resolution.

E1106 UseBeforeDeclaration (Error)

• Trigger: use of local binding before its declaration (if enforced).
• Source: 10-name-resolution (lexical scopes).

Stage 2: Types & Expressions

E1201 UnknownTypeName (Error)

• Trigger: type annotation refers to non-existent type.
• Source: 02-types.

E1202 TypeInferenceFailure (Error)

• Trigger: cannot infer local/private function return type (multiple incompatible returns).
• Source: 11-type-inference.

E1203 PublicReturnTypeMissing (Error)

• Trigger: public function missing explicit return type.
• Source: 11-type-inference.

E1204 CallArgumentCountMismatch (Error)

• Trigger: call has wrong number of arguments.
• Source: 01-lexical-and-syntax, 02-types.

E1205 CallArgumentTypeMismatch (Error)

• Trigger: argument type not assignable to parameter type.
• Source: 02-types.

E1206 AssignmentTypeMismatch (Error)

• Trigger: RHS not assignable to LHS type.
• Source: 02-types.

E1207 ReturnTypeMismatch (Error)

• Trigger: return expression type does not match function return type.
• Source: 02-types.

E1208 NonBooleanCondition (Error)

• Trigger: if/while condition is not bool.
• Source: 05-control-flow.

E1209 BinaryOperatorTypeMismatch (Error)

• Trigger: binary operator operands are incompatible.
• Source: 02-types.

E1210 UnaryOperatorTypeMismatch (Error)

• Trigger: unary operator applied to invalid type.
• Source: 02-types.

E1211 StructLiteralUnknownField (Error)

• Trigger: struct literal includes unknown field.
• Source: 02-types.

E1212 StructLiteralMissingField (Error)

• Trigger: struct literal omits required fields.
• Source: 02-types.

E1213 FieldAccessOnNonStruct (Error)

• Trigger: member access on non-struct value.
• Source: 02-types.

E1214 ImmutableAssignment (Error)

• Trigger: assignment to immutable binding (missing mut).
• Source: 02-types (mutability rules).

E1215 UseAfterMove (Error)

• Trigger: value used after move (non-copy type).
• Source: 02-types (move semantics).

E1216 EqualityTypeMismatch (Error)

• Trigger: == operands are not comparable or have incompatible types.
• Source: 02-types (equality semantics).

E1217 IdentityOnNonReference (Error)

• Trigger: === used on non-reference operands.
• Source: 02-types (reference identity).

E1218 OutArgumentNotMutable (Error)

• Trigger: out argument is not a mutable binding.
• Source: 03-memory-and-references.

E1219 RefOutArgumentNotLValue (Error)

• Trigger: ref/out arguments are not assignable lvalues.
• Source: 03-memory-and-references.

Stage 3: Enums, Match, Patterns

E1301 UnknownEnumPath (Error)

• Trigger: enum constructor references unknown enum/variant.
• Source: 04-enums-and-match.

E1302 EnumConstructorArityMismatch (Error)

• Trigger: enum constructor called with wrong number of arguments.
• Source: 04-enums-and-match.

E1303 UnqualifiedEnumConstructor (Error)

• Trigger: enum constructor invoked without Enum:: qualifier.
• Source: 04-enums-and-match.

E1304 MatchNonExhaustive (Error)

• Trigger: match does not cover all variants (and no _).
• Source: 04-enums-and-match.

E1305 MatchArmTypeMismatch (Error)

• Trigger: match arm expression types differ.
• Source: 04-enums-and-match.

E1306 DuplicatePatternBinding (Error)

• Trigger: pattern binds same name multiple times.
• Source: 04-enums-and-match.

E1307 PatternArityMismatch (Error)

• Trigger: enum pattern has wrong number of subpatterns.
• Source: 04-enums-and-match.

E1308 GuardTypeMismatch (Error)

• Trigger: when guard is not bool.
• Source: 04-enums-and-match.

Stage 4: Control Flow

E1401 BreakOutsideLoop (Error)

• Trigger: break used outside loop.
• Source: 05-control-flow.

E1402 ContinueOutsideLoop (Error)

• Trigger: continue used outside loop.
• Source: 05-control-flow.

W1403 UnreachableCode (Warning)

• Trigger: statement after return/break/continue in same block.
• Source: 05-control-flow.

Stage 5: Modules & Visibility

E1501 VisibilityViolation (Error)

• Trigger: access to non-pub item from another module.
• Source: 06-modules-and-visibility.

E1502 ModuleNotFound (Error)

• Trigger: mod declaration refers to a missing module file.
• Source: 06-modules-and-visibility.

W1503 UnusedImport (Warning)

• Trigger: use path never referenced.
• Source: 06-modules-and-visibility.

W1504 UnusedPrivateItem (Warning)

• Trigger: private item declared but never used in module.
• Source: 06-modules-and-visibility.

Stage 6: Contracts & Methods

E1601 ContractMethodMissingImpl (Error)

• Trigger: an explicitly declared type Type : Contract conformance is missing one or more required contract methods in impl Type blocks.
• Source: 09-contracts.

E1602 ContractImplSignatureMismatch (Error)

• Trigger: method implementation in impl Type for a declared type Type : Contract conformance does not match contract signature.
• Source: 09-contracts.

E1603 MethodDispatchAmbiguous (Error)

• Trigger: overloaded methods resolve ambiguously.
• Source: 12-method-dispatch.

E1604 InvalidContractReceiver (Error)

• Trigger: ref receiver does not satisfy contract method set.
• Source: 12-method-dispatch.

E1605 MethodLookupWithAliasFailure (Error)

• Trigger: method resolution fails due to alias target mismatch.
• Source: 12-method-dispatch, 10-name-resolution.

E1606 MethodNotFound (Error)

• Trigger: method call cannot be resolved for receiver type.
• Source: 12-method-dispatch.

E1607 ContractNotSatisfied (Error)

• Trigger: value typed as contract has no explicit conformance declaration (type Type : Contract) for the required contract.
• Source: 09-contracts, 12-method-dispatch.

Stage 7: Error Handling

E1701 QuestionOnNonResult (Error)

• Trigger: ? used on non-Result type.
• Source: 07-error-handling.

E1702 QuestionTypeMismatch (Error)

• Trigger: ? used where error type is incompatible with function return type.
• Source: 07-error-handling.

E1703 QuestionOutsideFunction (Error)

• Trigger: ? used outside a function body.
• Source: 07-error-handling.

Stage 8: Attributes

E1801 UnknownAttribute (Error)

• Trigger: attribute application references no declared attribute.
• Source: 01-lexical-and-syntax.

E1802 AttributeUnknownArgument (Error)

• Trigger: attribute application passes an argument not present in attribute declaration.
• Source: 01-lexical-and-syntax.

E1803 AttributeMissingRequiredArgument (Error)

• Trigger: required attribute parameter (without default) is not provided.
• Source: 01-lexical-and-syntax.

E1804 AttributeDuplicateArgument (Error)

• Trigger: same named argument provided more than once in attribute application.
• Source: 01-lexical-and-syntax.

E1805 AttributeArgumentTypeMismatch (Error)

• Trigger: argument expression type does not match declared parameter type.
• Source: 01-lexical-and-syntax.

E1508 DuplicateAttributeDeclarationTarget (Error)

• Trigger: attribute declaration target list repeats the same target kind more than once.
• Source: 01-lexical-and-syntax.

E1509 UnknownAttributeDeclarationTarget (Error)

• Trigger: attribute declaration target list uses an unsupported target kind.
• Source: 01-lexical-and-syntax.

E1510 AttributeTargetNotAllowed (Error)

• Trigger: attribute application site node kind is not included in attribute declaration target list.
• Source: 01-lexical-and-syntax.

Compiler mod diagnostics (platform spec)

• Mod- and generator-related diagnostics are specified in the E1801–E1899 band (Diagnostic code registry), Compiler Mod SDK, Mod host bridge, and analysis, query, and diagnostics facades; language-level meta items are removed — do not treat legacy draft paths as normative.

Notes

• Rules marked Warning can be toggled via AnalysisOptions.
• Some rules (question operator) may be deferred if v0.1 parser/AST doesn’t yet support them.