Correctly compute noUncheckedIndexedAccess effects on compound/increm…

…ent/decrement assignments (#58239)
microsoft · Apr 19, 2024 · aedd1b1 · aedd1b1
1 parent 3480321
commit aedd1b1
Show file tree

Hide file tree

Showing 6 changed files with 356 additions and 4 deletions.
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -33031,7 +33031,10 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                 error(node, Diagnostics.Index_signature_in_type_0_only_permits_reading, typeToString(apparentType));
             }
 
-            propType = (compilerOptions.noUncheckedIndexedAccess && !isAssignmentTarget(node)) ? getUnionType([indexInfo.type, missingType]) : indexInfo.type;
+            propType = indexInfo.type;
+            if (compilerOptions.noUncheckedIndexedAccess && getAssignmentTargetKind(node) !== AssignmentKind.Definite) {
+                propType = getUnionType([propType, missingType]);
+            }
             if (compilerOptions.noPropertyAccessFromIndexSignature && isPropertyAccessExpression(node)) {
                 error(right, Diagnostics.Property_0_comes_from_an_index_signature_so_it_must_be_accessed_with_0, unescapeLeadingUnderscores(right.escapedText));
             }
@@ -33626,9 +33629,17 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         }
 
         const effectiveIndexType = isForInVariableForNumericPropertyNames(indexExpression) ? numberType : indexType;
-        const accessFlags = isAssignmentTarget(node) ?
-            AccessFlags.Writing | (isGenericObjectType(objectType) && !isThisTypeParameter(objectType) ? AccessFlags.NoIndexSignatures : 0) :
-            AccessFlags.ExpressionPosition;
+        const assignmentTargetKind = getAssignmentTargetKind(node);
+        let accessFlags: AccessFlags;
+        if (assignmentTargetKind === AssignmentKind.None) {
+            accessFlags = AccessFlags.ExpressionPosition;
+        }
+        else {
+            accessFlags = AccessFlags.Writing | (isGenericObjectType(objectType) && !isThisTypeParameter(objectType) ? AccessFlags.NoIndexSignatures : 0);
+            if (assignmentTargetKind === AssignmentKind.Compound) {
+                accessFlags |= AccessFlags.ExpressionPosition;
+            }
+        }
         const indexedAccessType = getIndexedAccessTypeOrUndefined(objectType, effectiveIndexType, accessFlags, node) || errorType;
         return checkIndexedAccessIndexType(getFlowTypeOfAccessExpression(node, getNodeLinks(node).resolvedSymbol, indexedAccessType, indexExpression, checkMode), node);
     }

diff --git a/tests/baselines/reference/noUncheckedIndexedAccessCompoundAssignments.errors.txt b/tests/baselines/reference/noUncheckedIndexedAccessCompoundAssignments.errors.txt
@@ -0,0 +1,59 @@
+noUncheckedIndexedAccessCompoundAssignments.ts(3,1): error TS18048: 'stringMap.foo' is possibly 'undefined'.
+noUncheckedIndexedAccessCompoundAssignments.ts(4,3): error TS18048: 'stringMap.foo' is possibly 'undefined'.
+noUncheckedIndexedAccessCompoundAssignments.ts(5,1): error TS18048: 'stringMap.foo' is possibly 'undefined'.
+noUncheckedIndexedAccessCompoundAssignments.ts(6,1): error TS18048: 'stringMap.foo' is possibly 'undefined'.
+noUncheckedIndexedAccessCompoundAssignments.ts(7,3): error TS2532: Object is possibly 'undefined'.
+noUncheckedIndexedAccessCompoundAssignments.ts(8,1): error TS2532: Object is possibly 'undefined'.
+noUncheckedIndexedAccessCompoundAssignments.ts(9,3): error TS2532: Object is possibly 'undefined'.
+noUncheckedIndexedAccessCompoundAssignments.ts(10,1): error TS2532: Object is possibly 'undefined'.
+noUncheckedIndexedAccessCompoundAssignments.ts(11,1): error TS2532: Object is possibly 'undefined'.
+noUncheckedIndexedAccessCompoundAssignments.ts(12,1): error TS2532: Object is possibly 'undefined'.
+noUncheckedIndexedAccessCompoundAssignments.ts(13,1): error TS2532: Object is possibly 'undefined'.
+noUncheckedIndexedAccessCompoundAssignments.ts(14,1): error TS2532: Object is possibly 'undefined'.
+
+
+==== noUncheckedIndexedAccessCompoundAssignments.ts (12 errors) ====
+    // Each line should have one error
+    // for a total of 12 errors
+    stringMap.foo++;
+    ~~~~~~~~~~~~~
+!!! error TS18048: 'stringMap.foo' is possibly 'undefined'.
+    --stringMap.foo;
+      ~~~~~~~~~~~~~
+!!! error TS18048: 'stringMap.foo' is possibly 'undefined'.
+    stringMap.foo += 1;
+    ~~~~~~~~~~~~~
+!!! error TS18048: 'stringMap.foo' is possibly 'undefined'.
+    stringMap.foo *= 1;
+    ~~~~~~~~~~~~~
+!!! error TS18048: 'stringMap.foo' is possibly 'undefined'.
+    ++stringMap['foo'];
+      ~~~~~~~~~~~~~~~~
+!!! error TS2532: Object is possibly 'undefined'.
+    stringMap['foo']--;
+    ~~~~~~~~~~~~~~~~
+!!! error TS2532: Object is possibly 'undefined'.
+    ++stringMap[s];
+      ~~~~~~~~~~~~
+!!! error TS2532: Object is possibly 'undefined'.
+    stringMap[s]--;
+    ~~~~~~~~~~~~
+!!! error TS2532: Object is possibly 'undefined'.
+    numberMap[32]++;
+    ~~~~~~~~~~~~~
+!!! error TS2532: Object is possibly 'undefined'.
+    numberMap[32] += 1;
+    ~~~~~~~~~~~~~
+!!! error TS2532: Object is possibly 'undefined'.
+    numberMap[n]++;
+    ~~~~~~~~~~~~
+!!! error TS2532: Object is possibly 'undefined'.
+    numberMap[n] += 1;
+    ~~~~~~~~~~~~
+!!! error TS2532: Object is possibly 'undefined'.
+
+    declare const stringMap: { [s: string]: number };
+    declare const s: string;
+    declare const numberMap: { [n: number]: number };
+    declare const n: number;
+
diff --git a/tests/baselines/reference/noUncheckedIndexedAccessCompoundAssignments.js b/tests/baselines/reference/noUncheckedIndexedAccessCompoundAssignments.js
@@ -0,0 +1,40 @@
+//// [tests/cases/compiler/noUncheckedIndexedAccessCompoundAssignments.ts] ////
+
+//// [noUncheckedIndexedAccessCompoundAssignments.ts]
+// Each line should have one error
+// for a total of 12 errors
+stringMap.foo++;
+--stringMap.foo;
+stringMap.foo += 1;
+stringMap.foo *= 1;
+++stringMap['foo'];
+stringMap['foo']--;
+++stringMap[s];
+stringMap[s]--;
+numberMap[32]++;
+numberMap[32] += 1;
+numberMap[n]++;
+numberMap[n] += 1;
+
+declare const stringMap: { [s: string]: number };
+declare const s: string;
+declare const numberMap: { [n: number]: number };
+declare const n: number;
+
+
+//// [noUncheckedIndexedAccessCompoundAssignments.js]
+"use strict";
+// Each line should have one error
+// for a total of 12 errors
+stringMap.foo++;
+--stringMap.foo;
+stringMap.foo += 1;
+stringMap.foo *= 1;
+++stringMap['foo'];
+stringMap['foo']--;
+++stringMap[s];
+stringMap[s]--;
+numberMap[32]++;
+numberMap[32] += 1;
+numberMap[n]++;
+numberMap[n] += 1;
diff --git a/tests/baselines/reference/noUncheckedIndexedAccessCompoundAssignments.symbols b/tests/baselines/reference/noUncheckedIndexedAccessCompoundAssignments.symbols
@@ -0,0 +1,67 @@
+//// [tests/cases/compiler/noUncheckedIndexedAccessCompoundAssignments.ts] ////
+
+=== noUncheckedIndexedAccessCompoundAssignments.ts ===
+// Each line should have one error
+// for a total of 12 errors
+stringMap.foo++;
+>stringMap.foo : Symbol(__index, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 15, 26))
+>stringMap : Symbol(stringMap, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 15, 13))
+>foo : Symbol(__index, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 15, 26))
+
+--stringMap.foo;
+>stringMap.foo : Symbol(__index, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 15, 26))
+>stringMap : Symbol(stringMap, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 15, 13))
+>foo : Symbol(__index, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 15, 26))
+
+stringMap.foo += 1;
+>stringMap.foo : Symbol(__index, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 15, 26))
+>stringMap : Symbol(stringMap, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 15, 13))
+>foo : Symbol(__index, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 15, 26))
+
+stringMap.foo *= 1;
+>stringMap.foo : Symbol(__index, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 15, 26))
+>stringMap : Symbol(stringMap, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 15, 13))
+>foo : Symbol(__index, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 15, 26))
+
+++stringMap['foo'];
+>stringMap : Symbol(stringMap, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 15, 13))
+
+stringMap['foo']--;
+>stringMap : Symbol(stringMap, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 15, 13))
+
+++stringMap[s];
+>stringMap : Symbol(stringMap, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 15, 13))
+>s : Symbol(s, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 16, 13))
+
+stringMap[s]--;
+>stringMap : Symbol(stringMap, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 15, 13))
+>s : Symbol(s, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 16, 13))
+
+numberMap[32]++;
+>numberMap : Symbol(numberMap, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 17, 13))
+
+numberMap[32] += 1;
+>numberMap : Symbol(numberMap, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 17, 13))
+
+numberMap[n]++;
+>numberMap : Symbol(numberMap, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 17, 13))
+>n : Symbol(n, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 18, 13))
+
+numberMap[n] += 1;
+>numberMap : Symbol(numberMap, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 17, 13))
+>n : Symbol(n, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 18, 13))
+
+declare const stringMap: { [s: string]: number };
+>stringMap : Symbol(stringMap, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 15, 13))
+>s : Symbol(s, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 15, 28))
+
+declare const s: string;
+>s : Symbol(s, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 16, 13))
+
+declare const numberMap: { [n: number]: number };
+>numberMap : Symbol(numberMap, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 17, 13))
+>n : Symbol(n, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 17, 28))
+
+declare const n: number;
+>n : Symbol(n, Decl(noUncheckedIndexedAccessCompoundAssignments.ts, 18, 13))
+
diff --git a/tests/baselines/reference/noUncheckedIndexedAccessCompoundAssignments.types b/tests/baselines/reference/noUncheckedIndexedAccessCompoundAssignments.types
@@ -0,0 +1,153 @@
+//// [tests/cases/compiler/noUncheckedIndexedAccessCompoundAssignments.ts] ////
+
+=== noUncheckedIndexedAccessCompoundAssignments.ts ===
+// Each line should have one error
+// for a total of 12 errors
+stringMap.foo++;
+>stringMap.foo++ : number
+>                : ^^^^^^
+>stringMap.foo : number | undefined
+>              : ^^^^^^^^^^^^^^^^^^
+>stringMap : { [s: string]: number; }
+>          : ^^^^^^^^^^^^^^^^^^^^^^^^
+>foo : number | undefined
+>    : ^^^^^^^^^^^^^^^^^^
+
+--stringMap.foo;
+>--stringMap.foo : number
+>                : ^^^^^^
+>stringMap.foo : number | undefined
+>              : ^^^^^^^^^^^^^^^^^^
+>stringMap : { [s: string]: number; }
+>          : ^^^^^^^^^^^^^^^^^^^^^^^^
+>foo : number | undefined
+>    : ^^^^^^^^^^^^^^^^^^
+
+stringMap.foo += 1;
+>stringMap.foo += 1 : number
+>                   : ^^^^^^
+>stringMap.foo : number | undefined
+>              : ^^^^^^^^^^^^^^^^^^
+>stringMap : { [s: string]: number; }
+>          : ^^^^^^^^^^^^^^^^^^^^^^^^
+>foo : number | undefined
+>    : ^^^^^^^^^^^^^^^^^^
+>1 : 1
+>  : ^
+
+stringMap.foo *= 1;
+>stringMap.foo *= 1 : number
+>                   : ^^^^^^
+>stringMap.foo : number | undefined
+>              : ^^^^^^^^^^^^^^^^^^
+>stringMap : { [s: string]: number; }
+>          : ^^^^^^^^^^^^^^^^^^^^^^^^
+>foo : number | undefined
+>    : ^^^^^^^^^^^^^^^^^^
+>1 : 1
+>  : ^
+
+++stringMap['foo'];
+>++stringMap['foo'] : number
+>                   : ^^^^^^
+>stringMap['foo'] : number | undefined
+>                 : ^^^^^^^^^^^^^^^^^^
+>stringMap : { [s: string]: number; }
+>          : ^^^^^^^^^^^^^^^^^^^^^^^^
+>'foo' : "foo"
+>      : ^^^^^
+
+stringMap['foo']--;
+>stringMap['foo']-- : number
+>                   : ^^^^^^
+>stringMap['foo'] : number | undefined
+>                 : ^^^^^^^^^^^^^^^^^^
+>stringMap : { [s: string]: number; }
+>          : ^^^^^^^^^^^^^^^^^^^^^^^^
+>'foo' : "foo"
+>      : ^^^^^
+
+++stringMap[s];
+>++stringMap[s] : number
+>               : ^^^^^^
+>stringMap[s] : number | undefined
+>             : ^^^^^^^^^^^^^^^^^^
+>stringMap : { [s: string]: number; }
+>          : ^^^^^^^^^^^^^^^^^^^^^^^^
+>s : string
+>  : ^^^^^^
+
+stringMap[s]--;
+>stringMap[s]-- : number
+>               : ^^^^^^
+>stringMap[s] : number | undefined
+>             : ^^^^^^^^^^^^^^^^^^
+>stringMap : { [s: string]: number; }
+>          : ^^^^^^^^^^^^^^^^^^^^^^^^
+>s : string
+>  : ^^^^^^
+
+numberMap[32]++;
+>numberMap[32]++ : number
+>                : ^^^^^^
+>numberMap[32] : number | undefined
+>              : ^^^^^^^^^^^^^^^^^^
+>numberMap : { [n: number]: number; }
+>          : ^^^^^^^^^^^^^^^^^^^^^^^^
+>32 : 32
+>   : ^^
+
+numberMap[32] += 1;
+>numberMap[32] += 1 : number
+>                   : ^^^^^^
+>numberMap[32] : number | undefined
+>              : ^^^^^^^^^^^^^^^^^^
+>numberMap : { [n: number]: number; }
+>          : ^^^^^^^^^^^^^^^^^^^^^^^^
+>32 : 32
+>   : ^^
+>1 : 1
+>  : ^
+
+numberMap[n]++;
+>numberMap[n]++ : number
+>               : ^^^^^^
+>numberMap[n] : number | undefined
+>             : ^^^^^^^^^^^^^^^^^^
+>numberMap : { [n: number]: number; }
+>          : ^^^^^^^^^^^^^^^^^^^^^^^^
+>n : number
+>  : ^^^^^^
+
+numberMap[n] += 1;
+>numberMap[n] += 1 : number
+>                  : ^^^^^^
+>numberMap[n] : number | undefined
+>             : ^^^^^^^^^^^^^^^^^^
+>numberMap : { [n: number]: number; }
+>          : ^^^^^^^^^^^^^^^^^^^^^^^^
+>n : number
+>  : ^^^^^^
+>1 : 1
+>  : ^
+
+declare const stringMap: { [s: string]: number };
+>stringMap : { [s: string]: number; }
+>          : ^^^^^^^^^^^^^^^^^^^^^^^^
+>s : string
+>  : ^^^^^^
+
+declare const s: string;
+>s : string
+>  : ^^^^^^
+
+declare const numberMap: { [n: number]: number };
+>numberMap : { [n: number]: number; }
+>          : ^^^^^^^^^^^^^^^^^^^^^^^^
+>n : number
+>  : ^^^^^^
+
+declare const n: number;
+>n : number
+>  : ^^^^^^
+
diff --git a/tests/cases/compiler/noUncheckedIndexedAccessCompoundAssignments.ts b/tests/cases/compiler/noUncheckedIndexedAccessCompoundAssignments.ts
@@ -0,0 +1,22 @@
+// @strict: true
+// @noUncheckedIndexedAccess: true
+
+// Each line should have one error
+// for a total of 12 errors
+stringMap.foo++;
+--stringMap.foo;
+stringMap.foo += 1;
+stringMap.foo *= 1;
+++stringMap['foo'];
+stringMap['foo']--;
+++stringMap[s];
+stringMap[s]--;
+numberMap[32]++;
+numberMap[32] += 1;
+numberMap[n]++;
+numberMap[n] += 1;
+
+declare const stringMap: { [s: string]: number };
+declare const s: string;
+declare const numberMap: { [n: number]: number };
+declare const n: number;