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| 1 | namespace Syntax.Process is | |
| 2 | use Logging | |
| 3 | use Trees | |
| 4 | ||
| 5 | // Checks, once every body has compiled and the effect rounds have | |
| 6 | // settled, that the state compile-expressions left on the tree is | |
| 7 | // closed: every value's type is settled, with no inference | |
| 8 | // placeholder, no ERROR and no type parameter foreign to the body | |
| 9 | // that reads it, and every function literal's closure has settled | |
| 10 | // argument and return types. Generate-il reads that state as if it | |
| 11 | // were, and a slot the retry loop never converged reaches it as a | |
| 12 | // bad instruction or a runtime failure with nothing to say where | |
| 13 | // it came from. Reporting here names the node. | |
| 14 | // | |
| 15 | // Runs only on a build with no errors: a body that failed to | |
| 16 | // resolve legitimately leaves ERROR behind, and the diagnostic that | |
| 17 | // put it there is the one to read. | |
| 18 | class VERIFY_COMPILE_STATE: DefaultVisitor is | |
| 19 | _violations: int | |
| 20 | _uninferred: Collections.LIST[Semantic.Symbols.Variable] | |
| 21 | _uninferred_reads: Collections.LIST[Source.LOCATION] | |
| 22 | ||
| 23 | violations: int => _violations | |
| 24 | ||
| 25 | init( | |
| 26 | logger: Logger, | |
| 27 | symbol_table: Semantic.SYMBOL_TABLE, | |
| 28 | namespaces: Semantic.NAMESPACES | |
| 29 | ) | |
| 30 | is | |
| 31 | super.init(logger, symbol_table, namespaces) | |
| 32 | ||
| 33 | _uninferred = Collections.LIST[Semantic.Symbols.Variable]() | |
| 34 | _uninferred_reads = Collections.LIST[Source.LOCATION]() | |
| 35 | si | |
| 36 | ||
| 37 | apply(node: Node) is | |
| 38 | _violations = 0 | |
| 39 | _uninferred.clear() | |
| 40 | _uninferred_reads.clear() | |
| 41 | ||
| 42 | node.walk(self) | |
| 43 | si | |
| 44 | ||
| 45 | visit_default(node: Node) is | |
| 46 | if let expression: Expressions.Expression = node then | |
| 47 | _check_expression(expression) | |
| 48 | fi | |
| 49 | si | |
| 50 | ||
| 51 | visit(function: Expressions.FUNCTION) is | |
| 52 | if let closure: Semantic.Symbols.Closure = function.scope then | |
| 53 | _check_closure(function, closure) | |
| 54 | fi | |
| 55 | ||
| 56 | super.visit(function) | |
| 57 | si | |
| 58 | ||
| 59 | _check_expression(expression: Expressions.Expression) is | |
| 60 | let value = expression.value | |
| 61 | ||
| 62 | if !value? then | |
| 63 | return | |
| 64 | fi | |
| 65 | ||
| 66 | // A call that left a type parameter open makes the value's | |
| 67 | // own type carry it too, so the call is judged first and | |
| 68 | // what it reports stands for both. | |
| 69 | let omitted = _check_called_function(expression, value) | |
| 70 | ||
| 71 | let type = value.type | |
| 72 | ||
| 73 | if !type? then | |
| 74 | return | |
| 75 | fi | |
| 76 | ||
| 77 | _check_type(expression, "value", type, omitted) | |
| 78 | si | |
| 79 | ||
| 80 | // A call whose callee is still generic. The value's own type | |
| 81 | // catches a type parameter that reaches the result, and a | |
| 82 | // formal catches one an argument could pin, but a parameter | |
| 83 | // the callee names only in its body reaches neither: nothing | |
| 84 | // commits it, so nothing reports it, and the call emits a | |
| 85 | // methodref naming a parameter with no argument. | |
| 86 | _check_called_function(node: Node, value: IR.Values.Value) -> bool is | |
| 87 | let called = | |
| 88 | if let global_call: IR.Values.Call.GLOBAL = value then | |
| 89 | global_call.function | |
| 90 | elif let static_call: IR.Values.Call.STATIC = value then | |
| 91 | static_call.function | |
| 92 | elif let instance_call: IR.Values.Call.INSTANCE = value then | |
| 93 | instance_call.function | |
| 94 | elif let struct_call: IR.Values.Call.STRUCT = value then | |
| 95 | struct_call.function | |
| 96 | else | |
| 97 | null | |
| 98 | fi | |
| 99 | ||
| 100 | if !called? then | |
| 101 | return false | |
| 102 | fi | |
| 103 | ||
| 104 | let scope = _symbol_table.current_scope | |
| 105 | ||
| 106 | for argument in called.generic_arguments do | |
| 107 | if argument.has_function_generic_argument_foreign_to(scope) then | |
| 108 | _report_uninferred_type_argument(node) | |
| 109 | ||
| 110 | return true | |
| 111 | fi | |
| 112 | od | |
| 113 | ||
| 114 | false | |
| 115 | si | |
| 116 | ||
| 117 | _report_uninferred_type_argument(node: Node) is | |
| 118 | _violations = _violations + 1 | |
| 119 | ||
| 120 | _logger.error(node.location, "cannot infer type here") | |
| 121 | si | |
| 122 | ||
| 123 | _check_closure(function: Expressions.FUNCTION, closure: Semantic.Symbols.Closure) is | |
| 124 | let return_type = closure.return_type | |
| 125 | ||
| 126 | if return_type? then | |
| 127 | _check_type(function, "closure return", return_type, false) | |
| 128 | fi | |
| 129 | ||
| 130 | let index mut = 0 | |
| 131 | ||
| 132 | for argument in closure.arguments do | |
| 133 | _check_type(function, "closure argument {index}", argument, false) | |
| 134 | index = index + 1 | |
| 135 | od | |
| 136 | si | |
| 137 | ||
| 138 | _check_type(node: Node, what: string, type: Semantic.Types.Type, omitted_type_argument: bool) is | |
| 139 | let scope = _symbol_table.current_scope | |
| 140 | ||
| 141 | if let placeholder: Semantic.Types.INFERRED_VARIABLE_TYPE = type then | |
| 142 | _report_uninferred(placeholder.origin) | |
| 143 | _uninferred_reads.add(node.location) | |
| 144 | elif type.contains_inferred then | |
| 145 | // A placeholder inside the type rather than as the whole | |
| 146 | // of it - a constructor's type argument nothing pinned, | |
| 147 | // say - names a variable the body could not infer just as | |
| 148 | // a bare one does, and is the program's error rather than | |
| 149 | // the compiler's. | |
| 150 | let inner = _uninferred_within(type) | |
| 151 | ||
| 152 | if inner.count > 0 then | |
| 153 | for placeholder in inner do | |
| 154 | _report_uninferred(placeholder.origin) | |
| 155 | od | |
| 156 | ||
| 157 | _uninferred_reads.add(node.location) | |
| 158 | else | |
| 159 | _report(node, "{what} holds an inference placeholder: {type}") | |
| 160 | fi | |
| 161 | elif type.is_error then | |
| 162 | // Children are checked before their parents, so a read of | |
| 163 | // an uninferred local inside this value has already been | |
| 164 | // reported, and this ERROR is its consequence. | |
| 165 | if !_contains_uninferred_read(node.location) then | |
| 166 | _report(node, "{what} holds ERROR: {type}") | |
| 167 | fi | |
| 168 | elif type.has_function_generic_argument_foreign_to(scope) then | |
| 169 | // The parameter the call left open reaches the value, | |
| 170 | // and the call has already been reported. A parameter | |
| 171 | // no omission explains still reaches here. | |
| 172 | if !omitted_type_argument then | |
| 173 | _report(node, "{what} holds a type parameter foreign to this body: {type}") | |
| 174 | fi | |
| 175 | fi | |
| 176 | si | |
| 177 | ||
| 178 | // The placeholders a type holds within it, in the order the type | |
| 179 | // walk reaches them. | |
| 180 | _uninferred_within(type: Semantic.Types.Type) -> Collections.List[Semantic.Types.INFERRED_VARIABLE_TYPE] is | |
| 181 | let found = Collections.LIST[Semantic.Types.INFERRED_VARIABLE_TYPE]() | |
| 182 | ||
| 183 | type.walk( | |
| 184 | inner => | |
| 185 | if let placeholder: Semantic.Types.INFERRED_VARIABLE_TYPE = inner then | |
| 186 | found.add(placeholder) | |
| 187 | fi) | |
| 188 | ||
| 189 | found | |
| 190 | si | |
| 191 | ||
| 192 | // A local whose uses, assignments and initializer never gave it | |
| 193 | // a type is the program's error rather than the compiler's: | |
| 194 | // reported once, where the local is declared. | |
| 195 | _report_uninferred(variable: Semantic.Symbols.Variable) is | |
| 196 | if _uninferred.contains(variable) then | |
| 197 | return | |
| 198 | fi | |
| 199 | ||
| 200 | _uninferred.add(variable) | |
| 201 | _violations = _violations + 1 | |
| 202 | ||
| 203 | _logger.error(variable.location, "cannot infer type here") | |
| 204 | si | |
| 205 | ||
| 206 | _contains_uninferred_read(location: Source.LOCATION) -> bool is | |
| 207 | for read in _uninferred_reads do | |
| 208 | if location.contains(read) then | |
| 209 | return true | |
| 210 | fi | |
| 211 | od | |
| 212 | ||
| 213 | return false | |
| 214 | si | |
| 215 | ||
| 216 | _report(node: Node, message: string) is | |
| 217 | _violations = _violations + 1 | |
| 218 | ||
| 219 | _logger.error(node.location, "internal: unsettled compile state: {message}") | |
| 220 | si | |
| 221 | si | |
| 222 | si |