diff --git a/cl/doc.go b/cl/doc.go
index 3e331c065..764dd11dc 100644
--- a/cl/doc.go
+++ b/cl/doc.go
@@ -44,44 +44,75 @@ func (p *pkgCtx) docComments(decl clang.Cursor) []*ast.Comment {
 	return toLineComments(raw)
 }
 
+// cleanCommentLine strips the C/C++ comment markers and Doxygen/Javadoc
+// decoration that may appear on a single physical line of a raw comment,
+// returning just the human-readable content.
+//
+// Markers can appear at either end of the line because a raw comment reported
+// by libclang may concatenate multiple comment blocks (a plain "/* ... */"
+// banner immediately followed by a "/** ... */" doc block), which puts an
+// opener or closer mid-stream rather than only at the ends of the whole string.
+// The order matters: block openers/closers are removed first (so "Declarations
+// */" and "/**" collapse correctly), then line-comment markers, then a single
+// leading "*" decoration.
+func cleanCommentLine(line string) string {
+	line = strings.TrimSpace(line)
+	// Strip a leading block-opener: "/" followed by a run of "*" ("/*", "/**",
+	// "/***", banner "/*****").
+	if s, ok := strings.CutPrefix(line, "/"); ok {
+		if t := strings.TrimLeft(s, "*"); len(t) < len(s) {
+			line = strings.TrimSpace(t)
+		}
+	}
+	// Strip a trailing block-closer: a run of "*" followed by "/" ("*/", "**/",
+	// banner "*****/").
+	if s, ok := strings.CutSuffix(line, "/"); ok {
+		if t := strings.TrimRight(s, "*"); len(t) < len(s) {
+			line = strings.TrimSpace(t)
+		}
+	}
+	switch {
+	case strings.HasPrefix(line, "//"):
+		// Line-comment markers: "//", "///", "//!".
+		s := strings.TrimPrefix(line, "//")
+		s = strings.TrimPrefix(s, "/")
+		s = strings.TrimPrefix(s, "!")
+		line = strings.TrimPrefix(s, " ")
+	case strings.TrimRight(line, "*") == "":
+		// A line that is only "*" decoration (a blank Doxygen line) or a run
+		// of asterisks (a banner separator) carries no content.
+		line = ""
+	default:
+		// Drop a single Doxygen/Javadoc leading "*" decoration.
+		if s, ok := strings.CutPrefix(line, "* "); ok {
+			line = s
+		} else if s, ok := strings.CutPrefix(line, "*"); ok {
+			line = s
+		}
+	}
+	return line
+}
+
 // toLineComments converts a raw C/C++ documentation comment into a slice of Go
-// "//" line comments. It handles both block comments ("/* ... */", "/** ... */")
-// and consecutive line comments ("//", "///", "//!"), stripping the markers and
-// any common leading " * " decoration from block comments. It returns nil when
-// there is no meaningful content.
+// "//" line comments. It handles block comments ("/* ... */", "/** ... */"),
+// consecutive line comments ("//", "///", "//!"), and raw comments that
+// concatenate several blocks (e.g. "/* Declarations */\n/** ... */", which
+// libclang reports when a plain comment immediately precedes a doc comment on
+// the same declaration). The markers and any Doxygen/Javadoc "*" decoration are
+// stripped. It returns nil when there is no meaningful content.
 func toLineComments(raw string) []*ast.Comment {
 	raw = strings.TrimSpace(raw)
 	if raw == "" {
 		return nil
 	}
 
+	// Process the raw comment line by line. Because a single raw comment may
+	// contain more than one comment block, the opening ("/*", "/**", ...) and
+	// closing ("*/", "**/", ...) markers can appear on interior lines, not just
+	// at the very ends of the string, so each line is cleaned independently.
 	var lines []string
-	switch {
-	case strings.HasPrefix(raw, "/*"):
-		body := strings.TrimPrefix(raw, "/*")
-		body = strings.TrimSuffix(body, "*/")
-		for _, line := range strings.Split(body, "\n") {
-			line = strings.TrimSpace(line)
-			// Drop a Doxygen/Javadoc-style leading "*" decoration.
-			if line == "*" {
-				line = ""
-			} else if s, ok := strings.CutPrefix(line, "* "); ok {
-				line = s
-			} else if s, ok := strings.CutPrefix(line, "*"); ok {
-				line = s
-			}
-			lines = append(lines, line)
-		}
-	default:
-		for _, line := range strings.Split(raw, "\n") {
-			line = strings.TrimSpace(line)
-			line = strings.TrimPrefix(line, "//")
-			// Doxygen line-comment markers: "///" and "//!".
-			line = strings.TrimPrefix(line, "/")
-			line = strings.TrimPrefix(line, "!")
-			line = strings.TrimPrefix(line, " ")
-			lines = append(lines, line)
-		}
+	for _, line := range strings.Split(raw, "\n") {
+		lines = append(lines, cleanCommentLine(line))
 	}
 
 	// Trim leading/trailing blank lines that come from the markers being on
diff --git a/cl/doc_test.go b/cl/doc_test.go
new file mode 100644
index 000000000..1c6eb4910
--- /dev/null
+++ b/cl/doc_test.go
@@ -0,0 +1,125 @@
+/*
+ * Copyright (c) 2026 The XGo Authors (xgo.dev). All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package cl
+
+import (
+	"strings"
+	"testing"
+)
+
+func lineCommentsText(raw string) string {
+	comments := toLineComments(raw)
+	lines := make([]string, len(comments))
+	for i, c := range comments {
+		lines[i] = c.Text
+	}
+	return strings.Join(lines, "\n")
+}
+
+func TestToLineComments(t *testing.T) {
+	tests := []struct {
+		name string
+		raw  string
+		want string
+	}{
+		{
+			name: "empty",
+			raw:  "",
+			want: "",
+		},
+		{
+			name: "line_comment",
+			raw:  "/// A documented enum type.",
+			want: "// A documented enum type.",
+		},
+		{
+			name: "bang_line_comment",
+			raw:  "//! A bang documented item.",
+			want: "// A bang documented item.",
+		},
+		{
+			name: "plain_line_comment",
+			raw:  "// plain comment",
+			want: "// plain comment",
+		},
+		{
+			name: "single_line_block",
+			raw:  "/* simple */",
+			want: "// simple",
+		},
+		{
+			name: "doxygen_block",
+			raw:  "/**\n * A documented function.\n *\n * It adds two integers.\n */",
+			want: "// A documented function.\n//\n// It adds two integers.",
+		},
+		{
+			// A "/***" opener must not leak a stray "*" into a "// *" line.
+			name: "triple_star_opener",
+			raw:  "/***\n * Determine whether the given cursor represents a preprocessing\n * element.\n */",
+			want: "// Determine whether the given cursor represents a preprocessing\n// element.",
+		},
+		{
+			// Interior indentation after the "* " decoration is preserved.
+			name: "triple_star_preserves_indent",
+			raw:  "/***\n * Determine whether the given cursor represents a currently\n *  unexposed piece of the AST.\n */",
+			want: "// Determine whether the given cursor represents a currently\n//  unexposed piece of the AST.",
+		},
+		{
+			// Banner-style separators must collapse to blank lines, never
+			// emit rows of asterisks or a trailing "**/".
+			name: "banner_block",
+			raw:  "/**************\nSymbols and macros to supply platform-independent interfaces.\n**************/",
+			want: "// Symbols and macros to supply platform-independent interfaces.",
+		},
+		{
+			name: "block_with_star_prefix",
+			raw:  "/* uintptr_t is the C9X name for a type such that a\n * void* can be cast to uintptr_t and back.\n */",
+			want: "// uintptr_t is the C9X name for a type such that a\n// void* can be cast to uintptr_t and back.",
+		},
+		{
+			name: "block_no_star_prefix",
+			raw:  "/* line one\nline two */",
+			want: "// line one\n// line two",
+		},
+		{
+			name: "whitespace_only_block",
+			raw:  "/**\n *\n */",
+			want: "",
+		},
+		{
+			// libclang concatenates a plain banner and the following doc
+			// block into one raw comment; neither the interior "*/" nor the
+			// interior "/**" may leak into the output.
+			name: "multi_block_plain_then_doc",
+			raw:  "/* Declarations */\n  /**\n   * A declaration whose specific kind is not exposed.\n   */",
+			want: "// Declarations\n//\n// A declaration whose specific kind is not exposed.",
+		},
+		{
+			name: "inline_block_comment",
+			raw:  "/* Decl references */",
+			want: "// Decl references",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := lineCommentsText(tt.raw)
+			if got != tt.want {
+				t.Errorf("toLineComments(%q):\n got:\n%s\nwant:\n%s", tt.raw, got, tt.want)
+			}
+		})
+	}
+}
diff --git a/tool/_testc/clang-c-22.1.8/Index.go b/tool/_testc/clang-c-22.1.8/Index.go
index ebdade2b0..b76fa7df1 100644
--- a/tool/_testc/clang-c-22.1.8/Index.go
+++ b/tool/_testc/clang-c-22.1.8/Index.go
@@ -3495,7 +3495,6 @@ func (self CursorKind) IsTranslationUnit() c.Uint {
 	return 0
 }
 
-// *
 // Determine whether the given cursor represents a preprocessing
 // element, such as a preprocessor directive or macro instantiation.
 //
@@ -3504,7 +3503,6 @@ func (self CursorKind) IsPreprocessing() c.Uint {
 	return 0
 }
 
-// *
 // Determine whether the given cursor represents a currently
 //  unexposed piece of the AST (e.g., CXCursor_UnexposedStmt).
 //
diff --git a/tool/_testc/clang-c-22.1.8/Index/out.go b/tool/_testc/clang-c-22.1.8/Index/out.go
index 785c4bb45..259d2f7d0 100644
--- a/tool/_testc/clang-c-22.1.8/Index/out.go
+++ b/tool/_testc/clang-c-22.1.8/Index/out.go
@@ -3500,7 +3500,6 @@ func (_llcppg_param1 CursorKind) IsTranslationUnit() c.Uint {
 	return 0
 }
 
-// *
 // Determine whether the given cursor represents a preprocessing
 // element, such as a preprocessor directive or macro instantiation.
 //
@@ -3509,7 +3508,6 @@ func (_llcppg_param1 CursorKind) IsPreprocessing() c.Uint {
 	return 0
 }
 
-// *
 // Determine whether the given cursor represents a currently
 //  unexposed piece of the AST (e.g., CXCursor_UnexposedStmt).
 //