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fixed declarations that reference their own identifiers #910

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Merged
tomblind merged 4 commits into from
Aug 1, 2020
Merged

fixed declarations that reference their own identifiers #910

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6ac62c8
fixed variable declarations that reference their own identifiers in t…
tomblind Jul 31, 2020
630bbbc
Update src/transformation/utils/lua-ast.ts
tomblind Jul 31, 2020
2df9559
compiler error fix
tomblind Jul 31, 2020
ab1e56b
moved tests to assignments
tomblind Jul 31, 2020
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25 changes: 14 additions & 11 deletions src/transformation/utils/lua-ast.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -4,8 +4,7 @@ import * as lua from "../../LuaAST";
import { assert, castArray } from "../../utils";
import { TransformationContext } from "../context";
import { createExportedIdentifier, getIdentifierExportScope } from "./export";
import { peekScope, ScopeType } from "./scope";
import { isFunctionType } from "./typescript";
import { peekScope, ScopeType, Scope } from "./scope";
import { transformLuaLibFunction } from "./lualib";
import { LuaLibFeature } from "../../LuaLib";

Expand Down Expand Up @@ -129,6 +128,17 @@ export function createHoistableVariableDeclarationStatement(
return declaration;
}

function hasMultipleReferences(scope: Scope, identifiers: lua.Identifier | lua.Identifier[]) {
const scopeSymbols = scope.referencedSymbols;
if (!scopeSymbols) {
return false;
}

const referenceLists = castArray(identifiers).map(i => i.symbolId && scopeSymbols.get(i.symbolId));

return referenceLists.some(symbolRefs => symbolRefs && symbolRefs.length > 1);
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@Perryvw Perryvw Jul 31, 2020

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Maybe

Suggested change
return referenceLists.some(symbolRefs => symbolRefs && symbolRefs.length > 1);
return referenceLists.some(symbolRefs => symbolRefs?.length > 1);

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@tomblind tomblind Aug 1, 2020

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This change won't work as symbolRefs?.length resolves to number | undefined which can't be compared to a number like that. I could change it to something like (symbolRefs?.length || 0) > 1, but I feel like it looses clarity that way.

}

export function createLocalOrExportedOrGlobalDeclaration(
context: TransformationContext,
lhs: lua.Identifier | lua.Identifier[],
Expand Down Expand Up @@ -163,15 +173,8 @@ export function createLocalOrExportedOrGlobalDeclaration(
const isTopLevelVariable = scope.type === ScopeType.File;

if (context.isModule || !isTopLevelVariable) {
const isPossibleWrappedFunction =
!isFunctionDeclaration &&
tsOriginal &&
ts.isVariableDeclaration(tsOriginal) &&
tsOriginal.initializer &&
isFunctionType(context, context.checker.getTypeAtLocation(tsOriginal.initializer));

if (isPossibleWrappedFunction || scope.type === ScopeType.Switch) {
// Split declaration and assignment for wrapped function types to allow recursion
if (scope.type === ScopeType.Switch || (!isFunctionDeclaration && hasMultipleReferences(scope, lhs))) {
// Split declaration and assignment of identifiers that reference themselves in their declaration
declaration = lua.createVariableDeclarationStatement(lhs, undefined, tsOriginal);
assignment = lua.createAssignmentStatement(lhs, rhs, tsOriginal);
} else {
Expand Down
36 changes: 36 additions & 0 deletions test/unit/assignments.spec.ts
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Expand Up @@ -323,3 +323,39 @@ test.each([
return { r, o, a };
`.expectToMatchJsResult();
});

test("local variable declaration referencing self indirectly", () => {
util.testFunction`
let cb: () => void;

function foo(newCb: () => void) {
cb = newCb;
return "foo";
}

let bar = foo(() => {
bar = "bar";
});

cb();
return bar;
`.expectToMatchJsResult();
});

test("local multiple variable declaration referencing self indirectly", () => {
util.testFunction`
let cb: () => void;

function foo(newCb: () => void) {
cb = newCb;
return ["a", "foo", "c"];
}

let [a, bar, c] = foo(() => {
bar = "bar";
});

cb();
return bar;
`.expectToMatchJsResult();
});