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fix(eslint-plugin): [no-unnecessary-type-assertion] handle missing declarations #537

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Merged
merged 4 commits into from
Jun 9, 2019
Merged

fix(eslint-plugin): [no-unnecessary-type-assertion] handle missing declarations #537

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574e8bc
fix(eslint-plugin): [NUTA] false positive for null assign to undefined
bradzacher May 16, 2019
87ffc49
fix(eslint-plugin): [NUTA] handle missing declarations
bradzacher May 16, 2019
c7591cd
Merge branch 'master' into nuta-2
bradzacher Jun 7, 2019
1871854
fix: shonky master merge
bradzacher Jun 7, 2019
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5 changes: 5 additions & 0 deletions packages/eslint-plugin/src/rules/no-unnecessary-type-assertion.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -134,6 +134,11 @@ export default util.createRule<Options, MessageIds>({
*/
function isPossiblyUsedBeforeAssigned(node: ts.Expression): boolean {
const declaration = util.getDeclaration(checker, node);
if (!declaration) {
// don't know what the declaration is for some reason, so just assume the worst
return true;
}

if (
// non-strict mode doesn't care about used before assigned errors
isStrictCompilerOptionEnabled(compilerOptions, 'strictNullChecks') &&
Expand Down
13 changes: 11 additions & 2 deletions packages/eslint-plugin/src/util/types.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -140,8 +140,17 @@ export function isNullableType(
export function getDeclaration(
checker: ts.TypeChecker,
node: ts.Expression,
): ts.Declaration {
return checker.getSymbolAtLocation(node)!.declarations![0];
): ts.Declaration | null {
const symbol = checker.getSymbolAtLocation(node);
if (!symbol) {
return null;
}
const declarations = symbol.declarations;
if (!declarations) {
return null;
}

return declarations[0];
}

/**
Expand Down
40 changes: 40 additions & 0 deletions packages/eslint-plugin/tests/rules/no-unnecessary-type-assertion.test.ts
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Expand Up @@ -95,6 +95,21 @@ declare const str: string | null;

foo(str!);
`,
// https://github.com/typescript-eslint/typescript-eslint/issues/532
`
declare function a(a: string): any;
declare const b: string | null;
class Mx {
@a(b!)
private prop = 1;
}
`,
`
class Mx {
@a(b!)
private prop = 1;
}
`,
],

invalid: [
Expand Down Expand Up @@ -280,5 +295,30 @@ class Foo {
},
],
},
// https://github.com/typescript-eslint/typescript-eslint/issues/532
{
code: `
declare function a(a: string): any;
const b = 'asdf';
class Mx {
@a(b!)
private prop = 1;
}
`,
output: `
declare function a(a: string): any;
const b = 'asdf';
class Mx {
@a(b)
private prop = 1;
}
`,
errors: [
{
messageId: 'unnecessaryAssertion',
line: 5,
},
],
},
],
});