Differentiate between break and continue inside switch statements

rollup · Oct 17, 2019 · 7f01ea8 · 7f01ea8
1 parent 34269b0
commit 7f01ea8
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Showing 14 changed files with 71 additions and 16 deletions.
diff --git a/src/ast/ExecutionContext.ts b/src/ast/ExecutionContext.ts
@@ -3,6 +3,7 @@ import { PathTracker } from './utils/PathTracker';
 import ThisVariable from './variables/ThisVariable';
 
 interface ExecutionContextIgnore {
+	breakAndContinue: boolean;
 	breakStatements: boolean;
 	labels: Set<string>;
 	returnAwaitYield: boolean;
@@ -39,6 +40,7 @@ export function createHasEffectsContext(): HasEffectsContext {
 		breakFlow: BREAKFLOW_NONE,
 		called: new PathTracker(),
 		ignore: {
+			breakAndContinue: false,
 			breakStatements: false,
 			labels: new Set(),
 			returnAwaitYield: false

diff --git a/src/ast/nodes/ArrowFunctionExpression.ts b/src/ast/nodes/ArrowFunctionExpression.ts
@@ -58,6 +58,7 @@ export default class ArrowFunctionExpression extends NodeBase {
 		}
 		const { ignore, breakFlow } = context;
 		context.ignore = {
+			breakAndContinue: false,
 			breakStatements: false,
 			labels: new Set(),
 			returnAwaitYield: true

diff --git a/src/ast/nodes/BreakStatement.ts b/src/ast/nodes/BreakStatement.ts
@@ -8,7 +8,11 @@ export default class BreakStatement extends StatementBase {
 	type!: NodeType.tBreakStatement;
 
 	hasEffects(context: HasEffectsContext) {
-		if (!(this.label ? context.ignore.labels.has(this.label.name) : context.ignore.breakStatements))
+		if (
+			!(this.label
+				? context.ignore.labels.has(this.label.name)
+				: context.ignore.breakStatements || context.ignore.breakAndContinue)
+		)
 			return true;
 		context.breakFlow = new Set([this.label && this.label.name]);
 		return false;

diff --git a/src/ast/nodes/ContinueStatement.ts b/src/ast/nodes/ContinueStatement.ts
@@ -8,7 +8,9 @@ export default class ContinueStatement extends StatementBase {
 	type!: NodeType.tContinueStatement;
 
 	hasEffects(context: HasEffectsContext) {
-		if (!(this.label ? context.ignore.labels.has(this.label.name) : context.ignore.breakStatements))
+		if (
+			!(this.label ? context.ignore.labels.has(this.label.name) : context.ignore.breakAndContinue)
+		)
 			return true;
 		context.breakFlow = new Set([this.label && this.label.name]);
 		return false;

diff --git a/src/ast/nodes/DoWhileStatement.ts b/src/ast/nodes/DoWhileStatement.ts
@@ -11,11 +11,11 @@ export default class DoWhileStatement extends StatementBase {
 		if (this.test.hasEffects(context)) return true;
 		const {
 			breakFlow,
-			ignore: { breakStatements }
+			ignore: { breakAndContinue }
 		} = context;
-		context.ignore.breakStatements = true;
+		context.ignore.breakAndContinue = true;
 		if (this.body.hasEffects(context)) return true;
-		context.ignore.breakStatements = breakStatements;
+		context.ignore.breakAndContinue = breakAndContinue;
 		if (context.breakFlow instanceof Set && context.breakFlow.has(null)) {
 			context.breakFlow = breakFlow;
 		}

diff --git a/src/ast/nodes/ForInStatement.ts b/src/ast/nodes/ForInStatement.ts
@@ -36,11 +36,11 @@ export default class ForInStatement extends StatementBase {
 			return true;
 		const {
 			breakFlow,
-			ignore: { breakStatements }
+			ignore: { breakAndContinue }
 		} = context;
-		context.ignore.breakStatements = true;
+		context.ignore.breakAndContinue = true;
 		if (this.body.hasEffects(context)) return true;
-		context.ignore.breakStatements = breakStatements;
+		context.ignore.breakAndContinue = breakAndContinue;
 		context.breakFlow = breakFlow;
 		return false;
 	}

diff --git a/src/ast/nodes/ForStatement.ts b/src/ast/nodes/ForStatement.ts
@@ -27,11 +27,11 @@ export default class ForStatement extends StatementBase {
 			return true;
 		const {
 			breakFlow,
-			ignore: { breakStatements }
+			ignore: { breakAndContinue }
 		} = context;
-		context.ignore.breakStatements = true;
+		context.ignore.breakAndContinue = true;
 		if (this.body.hasEffects(context)) return true;
-		context.ignore.breakStatements = breakStatements;
+		context.ignore.breakAndContinue = breakAndContinue;
 		context.breakFlow = breakFlow;
 		return false;
 	}

diff --git a/src/ast/nodes/WhileStatement.ts b/src/ast/nodes/WhileStatement.ts
@@ -11,11 +11,11 @@ export default class WhileStatement extends StatementBase {
 		if (this.test.hasEffects(context)) return true;
 		const {
 			breakFlow,
-			ignore: { breakStatements }
+			ignore: { breakAndContinue }
 		} = context;
-		context.ignore.breakStatements = true;
+		context.ignore.breakAndContinue = true;
 		if (this.body.hasEffects(context)) return true;
-		context.ignore.breakStatements = breakStatements;
+		context.ignore.breakAndContinue = breakAndContinue;
 		context.breakFlow = breakFlow;
 		return false;
 	}

diff --git a/src/ast/nodes/shared/FunctionNode.ts b/src/ast/nodes/shared/FunctionNode.ts
@@ -74,6 +74,7 @@ export default class FunctionNode extends NodeBase {
 		);
 		const { breakFlow, ignore } = context;
 		context.ignore = {
+			breakAndContinue: false,
 			breakStatements: false,
 			labels: new Set(),
 			returnAwaitYield: true

diff --git a/test/form/samples/side-effects-switch-statements/_config.js b/test/form/samples/side-effects-switch-statements/_config.js
@@ -1,4 +1,3 @@
 module.exports = {
-	description: 'switch statements should be correctly tree-shaken',
-	options: { output: { name: 'myBundle' } }
+	description: 'switch statements should be correctly tree-shaken'
 };
diff --git a/test/form/samples/side-effects-switch-statements/_expected.js b/test/form/samples/side-effects-switch-statements/_expected.js
@@ -44,3 +44,12 @@ switch (globalThis.unknown) {
 		break;
 	case 'bar':
 }
+
+for (var i = 0; i < 4; i++) {
+	switch (i) {
+		case 0:
+		case 1:
+			continue;
+	}
+	effect();
+}
diff --git a/test/form/samples/side-effects-switch-statements/main.js b/test/form/samples/side-effects-switch-statements/main.js
@@ -65,3 +65,12 @@ switch (globalThis.unknown) {
 	case 'bar':
 		noEffect();
 }
+
+for (var i = 0; i < 4; i++) {
+	switch (i) {
+		case 0:
+		case 1:
+			continue;
+	}
+	effect();
+}
diff --git a/test/function/samples/switch-statement-nested-continue/_config.js b/test/function/samples/switch-statement-nested-continue/_config.js
@@ -0,0 +1,3 @@
+module.exports = {
+	description: 'treats continue different from break in switch statements'
+};
diff --git a/test/function/samples/switch-statement-nested-continue/main.js b/test/function/samples/switch-statement-nested-continue/main.js
@@ -0,0 +1,25 @@
+function getValueContinue() {
+	for (var i = 0; i < 4; i++) {
+		switch (i) {
+			case 0:
+			case 1:
+				continue;
+		}
+		return i;
+	}
+}
+
+assert.strictEqual(getValueContinue(), 2);
+
+function getValueBreak() {
+	for (var i = 0; i < 4; i++) {
+		switch (i) {
+			case 0:
+			case 1:
+				break;
+		}
+		return i;
+	}
+}
+
+assert.strictEqual(getValueBreak(), 0);