diff --git a/toolchain/check/handle_pattern_list.cpp b/toolchain/check/handle_pattern_list.cpp
index ab9b3f008c8b..0be2f7b5bc7f 100644
--- a/toolchain/check/handle_pattern_list.cpp
+++ b/toolchain/check/handle_pattern_list.cpp
@@ -157,6 +157,14 @@ auto HandleParseNode(Context& context, Parse::DefaultValueUnspecifiedId node_id)
   return context.TODO(node_id, "pattern default values");
 }
 
+auto HandleParseNode(Context& context,
+                     Parse::DefaultValueExprStartId /*node_id*/) -> bool {
+  // We want to check the default value expression as a normal expression,
+  // and not convert it into a pattern.
+  EndEmptyExprRegionForPattern(context);
+  return true;
+}
+
 auto HandleParseNode(Context& context, Parse::DefaultValuePatternId node_id)
     -> bool {
   // On entry, the top of the node stack should have an expression for the
@@ -205,6 +213,9 @@ auto HandleParseNode(Context& context, Parse::DefaultValuePatternId node_id)
        .default_value_id = default_value_id});
   context.node_stack().Push(node_id, default_value_inst_id);
 
+  // We turned off expr region for pattern checking while parsing the default
+  // value expression, so turn it back on again for further pattern checking.
+  BeginExprRegionForPattern(context);
   return true;
 }
 
diff --git a/toolchain/check/node_stack.h b/toolchain/check/node_stack.h
index e1e065691d82..7210f9d04f69 100644
--- a/toolchain/check/node_stack.h
+++ b/toolchain/check/node_stack.h
@@ -498,6 +498,7 @@ class NodeStack {
       case Parse::NodeKind::ContinueStatementStart:
       case Parse::NodeKind::CorePackageName:
       case Parse::NodeKind::CppPackageName:
+      case Parse::NodeKind::DefaultValueExprStart:
       case Parse::NodeKind::ExportIntroducer:
       case Parse::NodeKind::FileEnd:
       case Parse::NodeKind::FileStart:
diff --git a/toolchain/check/testdata/function/declaration/default_values.carbon b/toolchain/check/testdata/function/declaration/default_values.carbon
index 8ec9f4a85605..a277684f419f 100644
--- a/toolchain/check/testdata/function/declaration/default_values.carbon
+++ b/toolchain/check/testdata/function/declaration/default_values.carbon
@@ -64,6 +64,13 @@ library "[[@TEST_NAME]]";
 // CHECK:STDERR:
 fn Z(v: i32, x: i32 = 3, (y: i32 = 2, z: i32), w: i32 = 4, k: i32);
 
+// --- nested.carbon
+library "[[@TEST_NAME]]";
+
+//@dump-sem-ir-begin
+fn F(a: i32, (b: i32, (c: i32, (d: i32, e: i32))) = (1, (2, (3, 4))));
+//@dump-sem-ir-end
+
 // --- basic.carbon
 
 library "[[@TEST_NAME]]";
@@ -72,6 +79,96 @@ library "[[@TEST_NAME]]";
 fn F(x: i32 = 0);
 //@dump-sem-ir-end
 
+// CHECK:STDOUT: --- nested.carbon
+// CHECK:STDOUT:
+// CHECK:STDOUT: constants {
+// CHECK:STDOUT:   %int_32: Core.IntLiteral = int_value 32 [concrete]
+// CHECK:STDOUT:   %i32: type = class_type @Int, @Int(%int_32) [concrete]
+// CHECK:STDOUT:   %pattern_type.6b6: type = pattern_type %i32 [concrete]
+// CHECK:STDOUT:   %a.param_patt: %pattern_type.6b6 = value_param_pattern [concrete]
+// CHECK:STDOUT:   %a.patt: %pattern_type.6b6 = wrapper_binding_pattern a, %a.param_patt [concrete]
+// CHECK:STDOUT:   %b.param_patt: %pattern_type.6b6 = value_param_pattern [concrete]
+// CHECK:STDOUT:   %b.patt: %pattern_type.6b6 = wrapper_binding_pattern b, %b.param_patt [concrete]
+// CHECK:STDOUT:   %c.param_patt: %pattern_type.6b6 = value_param_pattern [concrete]
+// CHECK:STDOUT:   %c.patt: %pattern_type.6b6 = wrapper_binding_pattern c, %c.param_patt [concrete]
+// CHECK:STDOUT:   %d.param_patt: %pattern_type.6b6 = value_param_pattern [concrete]
+// CHECK:STDOUT:   %d.patt: %pattern_type.6b6 = wrapper_binding_pattern d, %d.param_patt [concrete]
+// CHECK:STDOUT:   %e.param_patt: %pattern_type.6b6 = value_param_pattern [concrete]
+// CHECK:STDOUT:   %e.patt: %pattern_type.6b6 = wrapper_binding_pattern e, %e.param_patt [concrete]
+// CHECK:STDOUT:   %tuple.type.e55: type = tuple_type (%i32, %i32) [concrete]
+// CHECK:STDOUT:   %pattern_type.394: type = pattern_type %tuple.type.e55 [concrete]
+// CHECK:STDOUT:   %.70d: %pattern_type.394 = tuple_pattern (%d.patt, %e.patt) [concrete]
+// CHECK:STDOUT:   %tuple.type.920: type = tuple_type (%i32, %tuple.type.e55) [concrete]
+// CHECK:STDOUT:   %pattern_type.e87: type = pattern_type %tuple.type.920 [concrete]
+// CHECK:STDOUT:   %.aa9: %pattern_type.e87 = tuple_pattern (%c.patt, %.70d) [concrete]
+// CHECK:STDOUT:   %tuple.type.007: type = tuple_type (%i32, %tuple.type.920) [concrete]
+// CHECK:STDOUT:   %pattern_type.802: type = pattern_type %tuple.type.007 [concrete]
+// CHECK:STDOUT:   %.203: %pattern_type.802 = tuple_pattern (%b.patt, %.aa9) [concrete]
+// CHECK:STDOUT:   %int_1.5b8: Core.IntLiteral = int_value 1 [concrete]
+// CHECK:STDOUT:   %int_2.ecc: Core.IntLiteral = int_value 2 [concrete]
+// CHECK:STDOUT:   %int_3.1ba: Core.IntLiteral = int_value 3 [concrete]
+// CHECK:STDOUT:   %int_4.0c1: Core.IntLiteral = int_value 4 [concrete]
+// CHECK:STDOUT:   %tuple.type.f94: type = tuple_type (Core.IntLiteral, Core.IntLiteral) [concrete]
+// CHECK:STDOUT:   %tuple.302: %tuple.type.f94 = tuple_value (%int_3.1ba, %int_4.0c1) [concrete]
+// CHECK:STDOUT:   %tuple.type.bd0: type = tuple_type (Core.IntLiteral, %tuple.type.f94) [concrete]
+// CHECK:STDOUT:   %tuple.b26: %tuple.type.bd0 = tuple_value (%int_2.ecc, %tuple.302) [concrete]
+// CHECK:STDOUT:   %tuple.type.c4f: type = tuple_type (Core.IntLiteral, %tuple.type.bd0) [concrete]
+// CHECK:STDOUT:   %tuple.326: %tuple.type.c4f = tuple_value (%int_1.5b8, %tuple.b26) [concrete]
+// CHECK:STDOUT:   %.19b: %pattern_type.802 = default_value_pattern %.203, index: 0 [concrete]
+// CHECK:STDOUT:   %F.type: type = fn_type @F [concrete]
+// CHECK:STDOUT:   %F: %F.type = struct_value () [concrete]
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: file {
+// CHECK:STDOUT:   %F.decl: %F.type = fn_decl @F [concrete = constants.%F] {
+// CHECK:STDOUT:     %a.param_patt: %pattern_type.6b6 = value_param_pattern [concrete = constants.%a.param_patt]
+// CHECK:STDOUT:     %a.patt: %pattern_type.6b6 = wrapper_binding_pattern a, %a.param_patt [concrete = constants.%a.patt]
+// CHECK:STDOUT:     %b.param_patt: %pattern_type.6b6 = value_param_pattern [concrete = constants.%b.param_patt]
+// CHECK:STDOUT:     %b.patt: %pattern_type.6b6 = wrapper_binding_pattern b, %b.param_patt [concrete = constants.%b.patt]
+// CHECK:STDOUT:     %c.param_patt: %pattern_type.6b6 = value_param_pattern [concrete = constants.%c.param_patt]
+// CHECK:STDOUT:     %c.patt: %pattern_type.6b6 = wrapper_binding_pattern c, %c.param_patt [concrete = constants.%c.patt]
+// CHECK:STDOUT:     %d.param_patt: %pattern_type.6b6 = value_param_pattern [concrete = constants.%d.param_patt]
+// CHECK:STDOUT:     %d.patt: %pattern_type.6b6 = wrapper_binding_pattern d, %d.param_patt [concrete = constants.%d.patt]
+// CHECK:STDOUT:     %e.param_patt: %pattern_type.6b6 = value_param_pattern [concrete = constants.%e.param_patt]
+// CHECK:STDOUT:     %e.patt: %pattern_type.6b6 = wrapper_binding_pattern e, %e.param_patt [concrete = constants.%e.patt]
+// CHECK:STDOUT:     %.loc4_47: %pattern_type.394 = tuple_pattern (%d.patt, %e.patt) [concrete = constants.%.70d]
+// CHECK:STDOUT:     %.loc4_48: %pattern_type.e87 = tuple_pattern (%c.patt, %.loc4_47) [concrete = constants.%.aa9]
+// CHECK:STDOUT:     %.loc4_49: %pattern_type.802 = tuple_pattern (%b.patt, %.loc4_48) [concrete = constants.%.203]
+// CHECK:STDOUT:     %.loc4_51: %pattern_type.802 = default_value_pattern %.loc4_49, index: 0 [concrete = constants.%.19b]
+// CHECK:STDOUT:   } {
+// CHECK:STDOUT:     %int_1: Core.IntLiteral = int_value 1 [concrete = constants.%int_1.5b8]
+// CHECK:STDOUT:     %int_2: Core.IntLiteral = int_value 2 [concrete = constants.%int_2.ecc]
+// CHECK:STDOUT:     %int_3: Core.IntLiteral = int_value 3 [concrete = constants.%int_3.1ba]
+// CHECK:STDOUT:     %int_4: Core.IntLiteral = int_value 4 [concrete = constants.%int_4.0c1]
+// CHECK:STDOUT:     %.loc4_66: %tuple.type.f94 = tuple_literal (%int_3, %int_4) [concrete = constants.%tuple.302]
+// CHECK:STDOUT:     %.loc4_67: %tuple.type.bd0 = tuple_literal (%int_2, %.loc4_66) [concrete = constants.%tuple.b26]
+// CHECK:STDOUT:     %.loc4_68: %tuple.type.c4f = tuple_literal (%int_1, %.loc4_67) [concrete = constants.%tuple.326]
+// CHECK:STDOUT:     %a.param: %i32 = value_param call_param0
+// CHECK:STDOUT:     %i32.loc4_9: type = type_literal constants.%i32 [concrete = constants.%i32]
+// CHECK:STDOUT:     %a: %i32 = wrapper_binding a, %a.param
+// CHECK:STDOUT:     %b.param: %i32 = value_param call_param1
+// CHECK:STDOUT:     %i32.loc4_18: type = type_literal constants.%i32 [concrete = constants.%i32]
+// CHECK:STDOUT:     %b: %i32 = wrapper_binding b, %b.param
+// CHECK:STDOUT:     %c.param: %i32 = value_param call_param2
+// CHECK:STDOUT:     %i32.loc4_27: type = type_literal constants.%i32 [concrete = constants.%i32]
+// CHECK:STDOUT:     %c: %i32 = wrapper_binding c, %c.param
+// CHECK:STDOUT:     %d.param: %i32 = value_param call_param3
+// CHECK:STDOUT:     %i32.loc4_36: type = type_literal constants.%i32 [concrete = constants.%i32]
+// CHECK:STDOUT:     %d: %i32 = wrapper_binding d, %d.param
+// CHECK:STDOUT:     %e.param: %i32 = value_param call_param4
+// CHECK:STDOUT:     %i32.loc4_44: type = type_literal constants.%i32 [concrete = constants.%i32]
+// CHECK:STDOUT:     %e: %i32 = wrapper_binding e, %e.param
+// CHECK:STDOUT:     %tuple.loc4_47: %tuple.type.e55 = tuple_value (%d.param, %e.param)
+// CHECK:STDOUT:     %tuple.loc4_48: %tuple.type.920 = tuple_value (%c.param, %tuple.loc4_47)
+// CHECK:STDOUT:     %tuple.loc4_49: %tuple.type.007 = tuple_value (%b.param, %tuple.loc4_48)
+// CHECK:STDOUT:     <elided>
+// CHECK:STDOUT:   }
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: fn @F(%a.param: %i32, %b.param: %i32, %c.param: %i32, %d.param: %i32, %e.param: %i32) default_values: {
+// CHECK:STDOUT:   constants.%tuple.326: %tuple.type.c4f = tuple_value (constants.%int_1.5b8, constants.%tuple.b26) [concrete]
+// CHECK:STDOUT: };
+// CHECK:STDOUT:
 // CHECK:STDOUT: --- basic.carbon
 // CHECK:STDOUT:
 // CHECK:STDOUT: constants {
diff --git a/toolchain/lex/token_kind.def b/toolchain/lex/token_kind.def
index bd5b90b2f4e8..29cf3eb19843 100644
--- a/toolchain/lex/token_kind.def
+++ b/toolchain/lex/token_kind.def
@@ -92,7 +92,8 @@ CARBON_SYMBOL_TOKEN(Backslash,           "\\")
 CARBON_SYMBOL_TOKEN(Caret,               "^")
 CARBON_TOKEN_WITH_VIRTUAL_NODE(
   CARBON_SYMBOL_TOKEN(Colon,               ":"))
-CARBON_SYMBOL_TOKEN(Equal,               "=")
+CARBON_TOKEN_WITH_VIRTUAL_NODE(
+  CARBON_SYMBOL_TOKEN(Equal,               "="))
 CARBON_SYMBOL_TOKEN(Exclaim,             "!")
 CARBON_SYMBOL_TOKEN(Greater,             ">")
 CARBON_SYMBOL_TOKEN(Less,                "<")
diff --git a/toolchain/parse/handle_pattern_list.cpp b/toolchain/parse/handle_pattern_list.cpp
index 8b9134b6f12b..bdf378af81d1 100644
--- a/toolchain/parse/handle_pattern_list.cpp
+++ b/toolchain/parse/handle_pattern_list.cpp
@@ -175,6 +175,10 @@ auto HandlePatternListElementCheckForDefaultValue(Context& context) -> void {
     return;
   }
 
+  // Add the first virtual node surrounding the value expr node, to facilitate
+  // handling in check.
+  context.AddLeafNode(NodeKind::DefaultValueExprStart, *equals_token);
+
   state.token = *equals_token;
   state.kind = StateKind::PatternListElementFinishDefaultValue;
   context.PushState(state);
diff --git a/toolchain/parse/node_kind.def b/toolchain/parse/node_kind.def
index e03c1eb070a7..ab645b46b918 100644
--- a/toolchain/parse/node_kind.def
+++ b/toolchain/parse/node_kind.def
@@ -242,6 +242,7 @@ CARBON_PARSE_NODE_KIND_PATTERN(FormBindingPattern)
 CARBON_PARSE_NODE_KIND_PATTERN(TemplateBindingName)
 CARBON_PARSE_NODE_KIND_PATTERN(CompileTimeBindingPatternTypeStart)
 CARBON_PARSE_NODE_KIND_PATTERN(CompileTimeBindingPattern)
+CARBON_PARSE_NODE_KIND_PATTERN(DefaultValueExprStart)
 CARBON_PARSE_NODE_KIND_PATTERN(DefaultValuePattern)
 CARBON_PARSE_NODE_KIND_EXPRESSION(DefaultValueUnspecified)
 
diff --git a/toolchain/parse/testdata/function/default_values.carbon b/toolchain/parse/testdata/function/default_values.carbon
index 4575139b3ea6..05de54f497d6 100644
--- a/toolchain/parse/testdata/function/default_values.carbon
+++ b/toolchain/parse/testdata/function/default_values.carbon
@@ -29,6 +29,7 @@ fn I(x: i32 = _);
 // CHECK:STDOUT:   │ │ │   ├─BindingPatternTypeStart ':'
 // CHECK:STDOUT:   │ │ │   ├─IntTypeLiteral 'i32'
 // CHECK:STDOUT:   │ │ │ ╭─LetBindingPattern ':'
+// CHECK:STDOUT:   │ │ │ ├─DefaultValueExprStart '='
 // CHECK:STDOUT:   │ │ │ ├─IntLiteral '0'
 // CHECK:STDOUT:   │ │ ├─DefaultValuePattern '='
 // CHECK:STDOUT:   │ ├─ExplicitParamList ')'
@@ -47,6 +48,7 @@ fn I(x: i32 = _);
 // CHECK:STDOUT:   │ │ │   │ ├─IntTypeLiteral 'i32'
 // CHECK:STDOUT:   │ │ │   ├─LetBindingPattern ':'
 // CHECK:STDOUT:   │ │ │ ╭─TuplePattern ')'
+// CHECK:STDOUT:   │ │ │ ├─DefaultValueExprStart '='
 // CHECK:STDOUT:   │ │ │ │ ╭─TupleLiteralStart '('
 // CHECK:STDOUT:   │ │ │ │ ├─IntLiteral '1'
 // CHECK:STDOUT:   │ │ │ │ ├─TupleLiteralComma ','
@@ -63,6 +65,7 @@ fn I(x: i32 = _);
 // CHECK:STDOUT:   │ │ │     ├─IntTypeLiteral 'i32'
 // CHECK:STDOUT:   │ │ │   ╭─LetBindingPattern ':'
 // CHECK:STDOUT:   │ │ │ ╭─UnusedPattern 'unused'
+// CHECK:STDOUT:   │ │ │ ├─DefaultValueExprStart '='
 // CHECK:STDOUT:   │ │ │ ├─IntLiteral '25'
 // CHECK:STDOUT:   │ │ ├─DefaultValuePattern '='
 // CHECK:STDOUT:   │ ├─ExplicitParamList ')'
@@ -80,6 +83,7 @@ fn I(x: i32 = _);
 // CHECK:STDOUT:   │ │ │ │   ├─BindingPatternTypeStart ':'
 // CHECK:STDOUT:   │ │ │ │   ├─IntTypeLiteral 'i32'
 // CHECK:STDOUT:   │ │ │ │ ╭─LetBindingPattern ':'
+// CHECK:STDOUT:   │ │ │ │ ├─DefaultValueExprStart '='
 // CHECK:STDOUT:   │ │ │ │ ├─IntLiteral '0'
 // CHECK:STDOUT:   │ │ │ ├─DefaultValuePattern '='
 // CHECK:STDOUT:   │ │ ├─ExplicitParamList ')'
@@ -94,6 +98,7 @@ fn I(x: i32 = _);
 // CHECK:STDOUT:   │ │ │   ├─BindingPatternTypeStart ':'
 // CHECK:STDOUT:   │ │ │   ├─IntTypeLiteral 'i32'
 // CHECK:STDOUT:   │ │ │ ╭─LetBindingPattern ':'
+// CHECK:STDOUT:   │ │ │ ├─DefaultValueExprStart '='
 // CHECK:STDOUT:   │ │ │ ├─DefaultValueUnspecified '_'
 // CHECK:STDOUT:   │ │ ├─DefaultValuePattern '='
 // CHECK:STDOUT:   │ ├─ExplicitParamList ')'
diff --git a/toolchain/parse/testdata/struct/struct_pattern.carbon b/toolchain/parse/testdata/struct/struct_pattern.carbon
index e9c05666ce29..1a5584593895 100644
--- a/toolchain/parse/testdata/struct/struct_pattern.carbon
+++ b/toolchain/parse/testdata/struct/struct_pattern.carbon
@@ -567,6 +567,7 @@ let {var _: i32} = {};
 // CHECK:STDOUT:   │ ╭─LetIntroducer 'let'
 // CHECK:STDOUT:   │ │ ╭─StructPatternStart '{'
 // CHECK:STDOUT:   │ │ │ ╭─InvalidParse '=' has_error
+// CHECK:STDOUT:   │ │ │ ├─DefaultValueExprStart '='
 // CHECK:STDOUT:   │ │ │ ├─IdentifierNameExpr 'y'
 // CHECK:STDOUT:   │ │ ├─DefaultValuePattern '=' has_error
 // CHECK:STDOUT:   │ ├─StructPattern '}' has_error
@@ -834,6 +835,7 @@ let {var _: i32} = {};
 // CHECK:STDOUT:   │ │ │   ╭─IdentifierNameExpr 'foo'
 // CHECK:STDOUT:   │ │ │   ├─IdentifierNameNotBeforeSignature 'y'
 // CHECK:STDOUT:   │ │ │ ╭─MemberAccessExpr '.'
+// CHECK:STDOUT:   │ │ │ ├─DefaultValueExprStart '='
 // CHECK:STDOUT:   │ │ │ ├─IdentifierNameExpr 'y'
 // CHECK:STDOUT:   │ │ ├─DefaultValuePattern '='
 // CHECK:STDOUT:   │ ├─StructPattern '}' has_error
@@ -959,6 +961,7 @@ let {var _: i32} = {};
 // CHECK:STDOUT:   │ ╭─LetIntroducer 'let'
 // CHECK:STDOUT:   │ │ ╭─StructPatternStart '{'
 // CHECK:STDOUT:   │ │ │ ╭─StringLiteral '"foo"'
+// CHECK:STDOUT:   │ │ │ ├─DefaultValueExprStart '='
 // CHECK:STDOUT:   │ │ │ ├─InvalidParse ',' has_error
 // CHECK:STDOUT:   │ │ ├─DefaultValuePattern '=' has_error
 // CHECK:STDOUT:   │ │ ├─PatternListComma ','
diff --git a/toolchain/parse/testdata/where_expr/fail_rewrite.carbon b/toolchain/parse/testdata/where_expr/fail_rewrite.carbon
index 90db37d1dbcb..55530e3ee832 100644
--- a/toolchain/parse/testdata/where_expr/fail_rewrite.carbon
+++ b/toolchain/parse/testdata/where_expr/fail_rewrite.carbon
@@ -79,6 +79,7 @@ fn AfterAnd(generic Z: Q where .R impls S and () = .A);
 // CHECK:STDOUT:   │ │ │   │ ├─IntTypeLiteral 'i32'
 // CHECK:STDOUT:   │ │ │   ├─WhereExpr 'where' has_error
 // CHECK:STDOUT:   │ │ │ ╭─CompileTimeBindingPattern ':' has_error
+// CHECK:STDOUT:   │ │ │ ├─DefaultValueExprStart '='
 // CHECK:STDOUT:   │ │ │ │ ╭─IdentifierNameNotBeforeSignature 'U'
 // CHECK:STDOUT:   │ │ │ ├─DesignatorExpr '.'
 // CHECK:STDOUT:   │ │ ├─DefaultValuePattern '=' has_error
@@ -101,6 +102,7 @@ fn AfterAnd(generic Z: Q where .R impls S and () = .A);
 // CHECK:STDOUT:   │ │ │   │ ├─ParenExpr ')'
 // CHECK:STDOUT:   │ │ │   ├─WhereExpr 'where' has_error
 // CHECK:STDOUT:   │ │ │ ╭─CompileTimeBindingPattern ':' has_error
+// CHECK:STDOUT:   │ │ │ ├─DefaultValueExprStart '='
 // CHECK:STDOUT:   │ │ │ ├─BoolTypeLiteral 'bool'
 // CHECK:STDOUT:   │ │ ├─DefaultValuePattern '=' has_error
 // CHECK:STDOUT:   │ ├─ExplicitParamList ')' has_error
@@ -120,6 +122,7 @@ fn AfterAnd(generic Z: Q where .R impls S and () = .A);
 // CHECK:STDOUT:   │ │ │   │ ├─DesignatorExpr '.'
 // CHECK:STDOUT:   │ │ │   ├─WhereExpr 'where' has_error
 // CHECK:STDOUT:   │ │ │ ╭─CompileTimeBindingPattern ':' has_error
+// CHECK:STDOUT:   │ │ │ ├─DefaultValueExprStart '='
 // CHECK:STDOUT:   │ │ │ ├─FloatTypeLiteral 'f32'
 // CHECK:STDOUT:   │ │ ├─DefaultValuePattern '=' has_error
 // CHECK:STDOUT:   │ ├─ExplicitParamList ')' has_error
@@ -139,6 +142,7 @@ fn AfterAnd(generic Z: Q where .R impls S and () = .A);
 // CHECK:STDOUT:   │ │ │   │ ├─DesignatorExpr '.' has_error
 // CHECK:STDOUT:   │ │ │   ├─WhereExpr 'where' has_error
 // CHECK:STDOUT:   │ │ │ ╭─CompileTimeBindingPattern ':' has_error
+// CHECK:STDOUT:   │ │ │ ├─DefaultValueExprStart '='
 // CHECK:STDOUT:   │ │ │ ├─UnsignedIntTypeLiteral 'u8'
 // CHECK:STDOUT:   │ │ ├─DefaultValuePattern '=' has_error
 // CHECK:STDOUT:   │ ├─ExplicitParamList ')' has_error
@@ -159,6 +163,7 @@ fn AfterAnd(generic Z: Q where .R impls S and () = .A);
 // CHECK:STDOUT:   │ │ │   │ ├─PostfixOperatorStar '*'
 // CHECK:STDOUT:   │ │ │   ├─WhereExpr 'where' has_error
 // CHECK:STDOUT:   │ │ │ ╭─CompileTimeBindingPattern ':' has_error
+// CHECK:STDOUT:   │ │ │ ├─DefaultValueExprStart '='
 // CHECK:STDOUT:   │ │ │ │ ╭─UnsignedIntTypeLiteral 'u64'
 // CHECK:STDOUT:   │ │ │ ├─PostfixOperatorStar '*'
 // CHECK:STDOUT:   │ │ ├─DefaultValuePattern '=' has_error
@@ -182,6 +187,7 @@ fn AfterAnd(generic Z: Q where .R impls S and () = .A);
 // CHECK:STDOUT:   │ │ │   │ ├─InfixOperatorPlus '+'
 // CHECK:STDOUT:   │ │ │   ├─WhereExpr 'where' has_error
 // CHECK:STDOUT:   │ │ │ ╭─CompileTimeBindingPattern ':' has_error
+// CHECK:STDOUT:   │ │ │ ├─DefaultValueExprStart '='
 // CHECK:STDOUT:   │ │ │ │ ╭─StructLiteralStart '{'
 // CHECK:STDOUT:   │ │ │ ├─StructLiteral '}'
 // CHECK:STDOUT:   │ │ ├─DefaultValuePattern '=' has_error
@@ -207,6 +213,7 @@ fn AfterAnd(generic Z: Q where .R impls S and () = .A);
 // CHECK:STDOUT:   │ │ │   │ ├─TupleLiteral ')'
 // CHECK:STDOUT:   │ │ │   ├─WhereExpr 'where' has_error
 // CHECK:STDOUT:   │ │ │ ╭─CompileTimeBindingPattern ':' has_error
+// CHECK:STDOUT:   │ │ │ ├─DefaultValueExprStart '='
 // CHECK:STDOUT:   │ │ │ │ ╭─IdentifierNameNotBeforeSignature 'A'
 // CHECK:STDOUT:   │ │ │ ├─DesignatorExpr '.'
 // CHECK:STDOUT:   │ │ ├─DefaultValuePattern '=' has_error
diff --git a/toolchain/parse/typed_nodes.h b/toolchain/parse/typed_nodes.h
index 09762792a911..39c655367802 100644
--- a/toolchain/parse/typed_nodes.h
+++ b/toolchain/parse/typed_nodes.h
@@ -377,13 +377,22 @@ using DefaultValueUnspecified =
     LeafNode<NodeKind::DefaultValueUnspecified, Lex::UnderscoreTokenIndex,
              NodeCategory::Expr>;
 
+struct DefaultValueExprStart {
+  static constexpr auto Kind =
+      NodeKind::DefaultValueExprStart.Define({.child_count = 0});
+  // This is a virtual token. The `=` token is owned by the
+  // DefaultValuePattern node.
+  Lex::EqualTokenIndex token;
+};
+
 // A pattern with a default value specified: `pattern = expr`.
 struct DefaultValuePattern {
   static constexpr auto Kind = NodeKind::DefaultValuePattern.Define(
-      {.category = NodeCategory::Pattern, .child_count = 2});
+      {.category = NodeCategory::Pattern, .child_count = 3});
 
   AnyPatternId pattern;
   Lex::EqualTokenIndex token;
+  DefaultValueExprStartId start;
   AnyExprId default_value_expr;
 };