Model other assignment variants as values
The previous PR only updated simple assignment expressions (where the lvalue is an identifier), this PR extends the same idea to all assignment variants. Note that there is one case that doesn't work yet, which is complex destructuring assignment as a value: ```javascript let x = makeObject(); x.foo(([[x]] = makeObject())); ``` What happens here is that we lower the destructuring to a series of steps: ``` tmp1: Destructure Const [ tmp0 ] = makeObject(); tmp2: Destructure Reassign [ x ] = tmp0; PropertyCall x, 'foo', [ tmp1 ] ``` Thankfully we can detect this case: if we have a const/let declaration with an lvalue, that's invalid. See the new error test case which shows we correctly detect & reject this case for now.
Joe Savona committed
Mar 21, 2023 at 10:01 UTC
ef34ca6cb044bca24890464e52a2e04b1984ba1b
8 files changed
+139
-18
compiler/forget/src/HIR/BuildHIR.ts
+32
-18
@@ -2029,13 +2029,20 @@ function lowerAssignment(
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});
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return { kind: "UnsupportedNode", node: lvalueNode, loc };
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}
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- return {
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- kind: "PropertyStore",
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- object,
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- property: property.node.name,
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- value,
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+ const temporary = buildTemporaryPlace(builder, loc);
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+ builder.push({
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+ id: makeInstructionId(0),
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+ lvalue: { ...temporary },
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+ value: {
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+ kind: "PropertyStore",
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+ object,
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+ property: property.node.name,
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+ value,
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+ loc,
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+ },
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loc,
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- };
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+ });
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+ return { kind: "LoadLocal", place: temporary, loc: temporary.loc };
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} else {
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if (!property.isExpression()) {
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builder.errors.push({
@@ -2047,13 +2054,20 @@ function lowerAssignment(
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return { kind: "UnsupportedNode", node: lvalueNode, loc };
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}
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const propertyPlace = lowerExpressionToTemporary(builder, property);
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- return {
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- kind: "ComputedStore",
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- object,
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- property: propertyPlace,
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- value,
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+ const temporary = buildTemporaryPlace(builder, loc);
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+ builder.push({
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+ id: makeInstructionId(0),
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+ lvalue: { ...temporary },
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+ value: {
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+ kind: "ComputedStore",
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+ object,
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+ property: propertyPlace,
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+ value,
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+ loc,
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+ },
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loc,
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- };
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+ });
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+ return { kind: "LoadLocal", place: temporary, loc: temporary.loc };
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}
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}
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case "ArrayPattern": {
@@ -2093,10 +2107,10 @@ function lowerAssignment(
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followups.push({ place: temp, path: element as NodePath<t.LVal> }); // TODO remove type cast
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}
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}
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- const temp = buildTemporaryPlace(builder, loc);
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+ const temporary = buildTemporaryPlace(builder, loc);
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builder.push({
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id: makeInstructionId(0),
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- lvalue: { ...temp },
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+ lvalue: { ...temporary },
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value: {
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kind: "Destructure",
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lvalue: {
@@ -2114,7 +2128,7 @@ function lowerAssignment(
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for (const { place, path } of followups) {
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lowerAssignment(builder, path.node.loc ?? loc, kind, path, place);
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}
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- return { kind: "LoadLocal", place: value, loc: value.loc };
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+ return { kind: "LoadLocal", place: temporary, loc: value.loc };
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}
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case "ObjectPattern": {
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const lvalue = lvaluePath as NodePath<t.ObjectPattern>;
@@ -2187,10 +2201,10 @@ function lowerAssignment(
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}
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}
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}
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- const temp = buildTemporaryPlace(builder, loc);
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+ const temporary = buildTemporaryPlace(builder, loc);
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builder.push({
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id: makeInstructionId(0),
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- lvalue: { ...temp },
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+ lvalue: { ...temporary },
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value: {
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kind: "Destructure",
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lvalue: {
@@ -2208,7 +2222,7 @@ function lowerAssignment(
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for (const { place, path } of followups) {
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lowerAssignment(builder, path.node.loc ?? loc, kind, path, place);
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}
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- return { kind: "LoadLocal", place: value, loc: value.loc };
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+ return { kind: "LoadLocal", place: temporary, loc: value.loc };
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}
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default: {
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builder.errors.push({
compiler/forget/src/ReactiveScopes/CodegenReactiveFunction.ts
+12
@@ -393,11 +393,23 @@ function codegenInstructionNullable(
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}
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switch (kind) {
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case InstructionKind.Const: {
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+ if (instr.lvalue !== null) {
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+ CompilerError.invariant(
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+ `Const declaration cannot be referenced as an expression`,
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+ instr.value.loc
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+ );
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+ }
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return createVariableDeclaration(instr.loc, "const", [
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t.variableDeclarator(codegenLValue(lvalue), value),
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]);
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}
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case InstructionKind.Let: {
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+ if (instr.lvalue !== null) {
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+ CompilerError.invariant(
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+ `Const declaration cannot be referenced as an expression`,
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+ instr.value.loc
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+ );
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+ }
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return createVariableDeclaration(instr.loc, "let", [
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t.variableDeclarator(codegenLValue(lvalue), value),
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]);
compiler/forget/src/__tests__/fixtures/compiler/call-args-assignment.expect.md
new
+30
@@ -0,0 +1,30 @@
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+
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+## Input
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+
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+```javascript
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+function Component(props) {
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+ let x = makeObject();
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+ x.foo((x = makeObject()));
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+ return x;
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+}
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+
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+```
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+
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+## Code
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+
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+```javascript
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+function Component(props) {
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+ const $ = React.unstable_useMemoCache(1);
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+ let x;
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+ if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
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+ x = makeObject();
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+ x.foo((x = makeObject()));
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+ $[0] = x;
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+ } else {
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+ x = $[0];
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+ }
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+ return x;
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+}
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+
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+```
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+
\ No newline at end of file
compiler/forget/src/__tests__/fixtures/compiler/call-args-assignment.js
new
+5
@@ -0,0 +1,5 @@
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+function Component(props) {
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+ let x = makeObject();
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+ x.foo((x = makeObject()));
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+ return x;
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+}
compiler/forget/src/__tests__/fixtures/compiler/call-args-destructuring-assignment.expect.md
new
+30
@@ -0,0 +1,30 @@
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+
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+## Input
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+
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+```javascript
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+function Component(props) {
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+ let x = makeObject();
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+ x.foo(([x] = makeObject()));
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+ return x;
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+}
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+
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+```
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+
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+## Code
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+
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+```javascript
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+function Component(props) {
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+ const $ = React.unstable_useMemoCache(1);
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+ let x;
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+ if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
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+ x = makeObject();
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+ x.foo(([x] = makeObject()));
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+ $[0] = x;
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+ } else {
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+ x = $[0];
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+ }
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+ return x;
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+}
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+
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+```
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+
\ No newline at end of file
compiler/forget/src/__tests__/fixtures/compiler/call-args-destructuring-assignment.js
new
+5
@@ -0,0 +1,5 @@
1
+function Component(props) {
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+ let x = makeObject();
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+ x.foo(([x] = makeObject()));
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+ return x;
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+}
compiler/forget/src/__tests__/fixtures/compiler/error.call-args-destructuring-asignment-complex.expect.md
new
+20
@@ -0,0 +1,20 @@
1
+
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+## Input
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+
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+```javascript
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+function Component(props) {
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+ let x = makeObject();
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+ x.foo(([[x]] = makeObject()));
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+ return x;
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+}
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+
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+```
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+
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+
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+## Error
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+
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+```
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+[ReactForget] Invariant: Const declaration cannot be referenced as an expression (3:3)
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+```
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+
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+
\ No newline at end of file
compiler/forget/src/__tests__/fixtures/compiler/error.call-args-destructuring-asignment-complex.js
new
+5
@@ -0,0 +1,5 @@
1
+function Component(props) {
2
+ let x = makeObject();
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+ x.foo(([[x]] = makeObject()));
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+ return x;
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+}