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| 1 | +//// [literalTypeWidening.ts] |
| 2 | +// Widening vs. non-widening literal types |
| 3 | + |
| 4 | +function f1() { |
| 5 | + const c1 = "hello"; // Widening type "hello" |
| 6 | + let v1 = c1; // Type string |
| 7 | + const c2 = c1; // Widening type "hello" |
| 8 | + let v2 = c2; // Type string |
| 9 | + const c3: "hello" = "hello"; // Type "hello" |
| 10 | + let v3 = c3; // Type "hello" |
| 11 | + const c4: "hello" = c1; // Type "hello" |
| 12 | + let v4 = c4; // Type "hello" |
| 13 | +} |
| 14 | + |
| 15 | +function f2(cond: boolean) { |
| 16 | + const c1 = cond ? "foo" : "bar"; // widening "foo" | widening "bar" |
| 17 | + const c2: "foo" | "bar" = c1; // "foo" | "bar" |
| 18 | + const c3 = cond ? c1 : c2; // "foo" | "bar" |
| 19 | + const c4 = cond ? c3 : "baz"; // "foo" | "bar" | widening "baz" |
| 20 | + const c5: "foo" | "bar" | "baz" = c4; // "foo" | "bar" | "baz" |
| 21 | + let v1 = c1; // string |
| 22 | + let v2 = c2; // "foo" | "bar" |
| 23 | + let v3 = c3; // "foo" | "bar" |
| 24 | + let v4 = c4; // string |
| 25 | + let v5 = c5; // "foo" | "bar" | "baz" |
| 26 | +} |
| 27 | + |
| 28 | +function f3() { |
| 29 | + const c1 = 123; // Widening type 123 |
| 30 | + let v1 = c1; // Type number |
| 31 | + const c2 = c1; // Widening type 123 |
| 32 | + let v2 = c2; // Type number |
| 33 | + const c3: 123 = 123; // Type 123 |
| 34 | + let v3 = c3; // Type 123 |
| 35 | + const c4: 123 = c1; // Type 123 |
| 36 | + let v4 = c4; // Type 123 |
| 37 | +} |
| 38 | + |
| 39 | +function f4(cond: boolean) { |
| 40 | + const c1 = cond ? 123 : 456; // widening 123 | widening 456 |
| 41 | + const c2: 123 | 456 = c1; // 123 | 456 |
| 42 | + const c3 = cond ? c1 : c2; // 123 | 456 |
| 43 | + const c4 = cond ? c3 : 789; // 123 | 456 | widening 789 |
| 44 | + const c5: 123 | 456 | 789 = c4; // 123 | 456 | 789 |
| 45 | + let v1 = c1; // number |
| 46 | + let v2 = c2; // 123 | 456 |
| 47 | + let v3 = c3; // 123 | 456 |
| 48 | + let v4 = c4; // number |
| 49 | + let v5 = c5; // 123 | 456 | 789 |
| 50 | +} |
| 51 | + |
| 52 | +function f5() { |
| 53 | + const c1 = "foo"; |
| 54 | + let v1 = c1; |
| 55 | + const c2: "foo" = "foo"; |
| 56 | + let v2 = c2; |
| 57 | + const c3 = "foo" as "foo"; |
| 58 | + let v3 = c3; |
| 59 | + const c4 = <"foo">"foo"; |
| 60 | + let v4 = c4; |
| 61 | +} |
| 62 | + |
| 63 | +// Repro from #10898 |
| 64 | + |
| 65 | +type FAILURE = "FAILURE"; |
| 66 | +const FAILURE = "FAILURE"; |
| 67 | + |
| 68 | +type Result<T> = T | FAILURE; |
| 69 | + |
| 70 | +function doWork<T>(): Result<T> { |
| 71 | + return FAILURE; |
| 72 | +} |
| 73 | + |
| 74 | +function isSuccess<T>(result: Result<T>): result is T { |
| 75 | + return !isFailure(result); |
| 76 | +} |
| 77 | + |
| 78 | +function isFailure<T>(result: Result<T>): result is FAILURE { |
| 79 | + return result === FAILURE; |
| 80 | +} |
| 81 | + |
| 82 | +function increment(x: number): number { |
| 83 | + return x + 1; |
| 84 | +} |
| 85 | + |
| 86 | +let result = doWork<number>(); |
| 87 | + |
| 88 | +if (isSuccess(result)) { |
| 89 | + increment(result); |
| 90 | +} |
| 91 | + |
| 92 | +// Repro from #10898 |
| 93 | + |
| 94 | +type TestEvent = "onmouseover" | "onmouseout"; |
| 95 | + |
| 96 | +function onMouseOver(): TestEvent { return "onmouseover"; } |
| 97 | + |
| 98 | +let x = onMouseOver(); |
| 99 | + |
| 100 | +//// [literalTypeWidening.js] |
| 101 | +// Widening vs. non-widening literal types |
| 102 | +function f1() { |
| 103 | + var c1 = "hello"; // Widening type "hello" |
| 104 | + var v1 = c1; // Type string |
| 105 | + var c2 = c1; // Widening type "hello" |
| 106 | + var v2 = c2; // Type string |
| 107 | + var c3 = "hello"; // Type "hello" |
| 108 | + var v3 = c3; // Type "hello" |
| 109 | + var c4 = c1; // Type "hello" |
| 110 | + var v4 = c4; // Type "hello" |
| 111 | +} |
| 112 | +function f2(cond) { |
| 113 | + var c1 = cond ? "foo" : "bar"; // widening "foo" | widening "bar" |
| 114 | + var c2 = c1; // "foo" | "bar" |
| 115 | + var c3 = cond ? c1 : c2; // "foo" | "bar" |
| 116 | + var c4 = cond ? c3 : "baz"; // "foo" | "bar" | widening "baz" |
| 117 | + var c5 = c4; // "foo" | "bar" | "baz" |
| 118 | + var v1 = c1; // string |
| 119 | + var v2 = c2; // "foo" | "bar" |
| 120 | + var v3 = c3; // "foo" | "bar" |
| 121 | + var v4 = c4; // string |
| 122 | + var v5 = c5; // "foo" | "bar" | "baz" |
| 123 | +} |
| 124 | +function f3() { |
| 125 | + var c1 = 123; // Widening type 123 |
| 126 | + var v1 = c1; // Type number |
| 127 | + var c2 = c1; // Widening type 123 |
| 128 | + var v2 = c2; // Type number |
| 129 | + var c3 = 123; // Type 123 |
| 130 | + var v3 = c3; // Type 123 |
| 131 | + var c4 = c1; // Type 123 |
| 132 | + var v4 = c4; // Type 123 |
| 133 | +} |
| 134 | +function f4(cond) { |
| 135 | + var c1 = cond ? 123 : 456; // widening 123 | widening 456 |
| 136 | + var c2 = c1; // 123 | 456 |
| 137 | + var c3 = cond ? c1 : c2; // 123 | 456 |
| 138 | + var c4 = cond ? c3 : 789; // 123 | 456 | widening 789 |
| 139 | + var c5 = c4; // 123 | 456 | 789 |
| 140 | + var v1 = c1; // number |
| 141 | + var v2 = c2; // 123 | 456 |
| 142 | + var v3 = c3; // 123 | 456 |
| 143 | + var v4 = c4; // number |
| 144 | + var v5 = c5; // 123 | 456 | 789 |
| 145 | +} |
| 146 | +function f5() { |
| 147 | + var c1 = "foo"; |
| 148 | + var v1 = c1; |
| 149 | + var c2 = "foo"; |
| 150 | + var v2 = c2; |
| 151 | + var c3 = "foo"; |
| 152 | + var v3 = c3; |
| 153 | + var c4 = "foo"; |
| 154 | + var v4 = c4; |
| 155 | +} |
| 156 | +var FAILURE = "FAILURE"; |
| 157 | +function doWork() { |
| 158 | + return FAILURE; |
| 159 | +} |
| 160 | +function isSuccess(result) { |
| 161 | + return !isFailure(result); |
| 162 | +} |
| 163 | +function isFailure(result) { |
| 164 | + return result === FAILURE; |
| 165 | +} |
| 166 | +function increment(x) { |
| 167 | + return x + 1; |
| 168 | +} |
| 169 | +var result = doWork(); |
| 170 | +if (isSuccess(result)) { |
| 171 | + increment(result); |
| 172 | +} |
| 173 | +function onMouseOver() { return "onmouseover"; } |
| 174 | +var x = onMouseOver(); |
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